Catalog Pyroelectric & Multispectral Detectors uncooled highly stable high performance highest quality. multi color.

Transcription

1 Catalog 203 multi color gas analysis Pyroelectric & Multispectral Detectors uncooled highly stable high performance highest quality

2 Product Group Outlines 203 Group Channel Housing Aperture size [mm] Chip size [mm] Current/ Voltage Mode JFET/ OpAmp Low Micro Compensated Beamsplitter. Detectivity [ 8 cm(hz /2 )/W] Related es (available on request) Page Standard Products LIE200 single TO8 Ø x.4 CM JFET LIE202 single TO8 Ø x.4 VM JFET 4.0 LIE20 26 LIE26 single TO8 Ø x.4 VM JFET x LIE36 single TO x x 2.0 VM JFET x 4.0 LIE LME302 single TO x x 2.0 VM JFET x 6.0 LME300; LME30; 32 LME36 single TO x x 2.0 VM JFET x x 4.0 LME LME335 single TO x x 2.0 CM OpAmp x x LME336 NEW single TO x x 2.0 CM OpAmp x x 4.0 LME34; LME345; 38 LME35 single TO x x 2.0 CM OpAmp x.8 LME LME352 NEW single TO x x 2.0 CM OpAmp x.5 42 LME50 single TO x x 3.0 CM none x LME500; LME LME55 single TO x x 3.0 CM OpAmp x 2.5 LME54 46 Extended Products LIE32 single TO393 Ø 5.0 Ø 2.0 VM JFET LIE32f single TO393 Ø 5.0 Ø 2.0 VM JFET LIE332f single TO393 Ø 5.0 Ø.3 VM JFET 2.8 LIE Multi Color Products LIM0 quad TO82 Ø x 2.2 VM JFET x 0.8 LIM02 58 LIM032 dual TO x x 2.2 VM JFET x LIM054 quad TO x x 2.2 CM OpAmp x 0.42 LIM LIM2 NEW dual TO464.5 x.7.0 x.4 VM JFET LIM24 quad TO82 Ø x 2.0 VM JFET x 4.5 LIM22; LIM4 66 LIM222 dual TO394.8 x x.8 VM JFET x 4.5 LIM252; LIM22; LIM52 68 LIM253 NEW three TO395 Ø x.3 VM JFET x 3.5 LIM53 70 LIM262 dual TO395.8 x x.8 CM OpAmp x 4.5 LIM62 72 LIM34 quad TO82 Ø x 2.0 VM JFET x 3.5 LIM4 74 LMM244 quad TO88 Ø x 2.0 CM OpAmp x x 6.0 LMM44; LMM Variable Color Products LFP304L tunable TO82 Ø x 2.0 CM OpAmp x x LFP3950L tunable TO82 Ø x 2.0 CM OpAmp x x LFP805 NEW tunable TO82 Ø x 2.0 CM OpAmp x x

3 Contents Introduction 5 The Company 5 Sensor Division s Abilities 6 Pyroelectric Detectors and their Applications 8 New Products Standard Products 23 Extended Products 49 Multi Color Products 57 Variable Color Products 79 IR Filters and Windows 87 Description 88 Typical Filter Plots 95 Spectral Emission of IR Sources Detector Basics 3 Thermal Conversion 5 Thermal to Electrical Conversion 6 Electrical Conversion 7 Voltage Mode Current Mode 6 Infrared Sources 20 Low Noise Power Supply 2 Advanced Features 23 Pyroelectric Detectors with JFET Source Follower or integrated CMOS 24 OpAmp A Comparison Microphonic Effect in Pyroelectric Detectors 28 Beamsplitter Detectors Even for the narrowest Signal Beams 35 Basics and Application of Variable Color Products 37 Temperature Behavior 5 Introduction 52 Temperature dependent Components within the Pyroelectric Detector 52 The Effects of Temperature Variation on overall Detector Performance 56 Variation of ambient Temperature and Temperature Compensation 62 Summary 66 3

4 Contents JFET and OpAmp 67 Standard JFET For single and multi color detectors 68 Special JFET Design for single and multi color detectors (on request) 70 OpAmp2 CMOS very low power OpAmp for single and multi color 72 detectors OpAmp3 CMOS very low power OpAmp for use in single supply 74 detectors and low current detectors Handling Precautions 77 Electrostatic Discharge (ESD) Sensitivity and Protection 78 Soldering 79 Mechanical Stress 79 Cleaning 80 Simple functional Test 80 4

5 The Company With headquarters in one of the leading European R&D centers, Dresden/Germany, InfraTec GmbH is focussed on high quality products and services based on vast expertise in infrared technology. Founded in 99 InfraTec with its Sensor and Infrared Measurement Division has own development and production facilities and a professional staff of more than 200 employees in Dresden and its worldwide subsidiaries. Sensor Division The Sensor Division is staffed by technical personnel completely familiar with all facets of the design, manufacture, test and application of pyroelectric detectors. The division is fully equipped with an inhouse capability for wafer processing, hybrid packaging, hermetic encapsulation, automated bonding and final testing. From protoes to high volume production, we take pride in the unequaled quality and performance of our detectors and our demonstrated ability to respond to and support our customers requirements in a timely and efficient manner. InfraTec s extensive standard pyroelectric detector line is constantly being enhanced. It includes many innovative devices such as multi color detectors with integrated beamsplitter and variable (tunable) color detectors (MOEMS based FabryPérotInterferometer). Infrared Measurement Division InfraTec s Infrared Measurement Division offers a complete assortment of more than 50 different camera models and turnkey system solutions for a wide range of thermographic applications. Starting with mobile and stationary microbolometer cameras up to cooled highend thermographic systems of the series ImageIR that has been developed and manufactured by InfraTec and that is being equipped with focal plane array photon detectors of different es (lnsb, MCT and QWIP) and formats from (320 x 256) up to (,280 x,024) IR pixel. Depending on the e of detector and the camera equipment frame rates of up to 4,500 Hz can be achieved, the ical temperature resolution is better than 0.02 K. Applicationspecific software packages for data acquisition and evaluation complete its range of highquality products. Our Corporate Philosophy InfraTec is committed to become the most customer oriented infrared technology and pyroelectric detector manufacturer in the world. Throughout the development to production cycle of our customers projects or instruments, we take particular pride in the responsiveness all of our employees have demonstrated. Our operating philosophy is based in large part on the belief that our success can be attributed not only to our employees high degree of motivation but also to the close working relationships we have established with our customers over the years. We have taken particular care in selecting our technical sales representatives worldwide to insure that they operate under the same philosophy. Together, we are eager to provide application assistance and work closely with you to arrive at the optimum detector specifications for your requirement. We look forward to hearing from you. 5

6 Sensor Division s Abilities Production The detector production department has all necessary technologies and equipment along with a 700 m 2 cleanroom at their disposal at the company headquarters in Dresden. With this, we have all competencies gathered up, beginning with the physical vapor deposition of electrodes on LiTaO 3 wafers and detector assembly to final electrooptical measurements. Our personnel is familiar with modern techniques of simulation, production and testing as well as with various applications of our infrared detectors. Thus, we produce protoes, small batches and large quantities with highest quality. We can guarantee longterm competencies in an everchanging pyroelectric detector market. High quality also requires good organisation, documentation and investments. These requirements form our corecompetencies, which ensure our permanent success in the international market: Patterning of lithium tantalate wafers Crystal characterization Vacuum coating Infrared absorbent layer Spectral measurements of IR filters, characterization and mounting % wafer testing for transmittance, blocking and temperature drift Adhesive bonding technology for infrared windows and IR filters; soldered windows are available for special applications Detector Assembly COB in TO metal housings Gold wire bonding at low temperatures Leakproof housings filled with % N 2 Description and InfraTec part number Part number: S8700 every device design is given its own unique part number Description: LIE202X005 describes the detector e and its filter or window, detectors with customized features are all Xes LIE: LiTaO 3 & InfraTec & Einelementig (single element) LIM: LiTaO 3 & InfraTec & Multi color LME: LiTaO 3 & low Microphonic effect & Einelementig (single element) LMM: LiTaO 3 & low Microphonic effect & Multi color LFP: LiTaO 3 & FabryPérot 6

7 Sensor Division s Abilities Research and Development Permanent research and development of new sensor technologies are indispensable in order to meet the customer s expectations as well as our own detector production requirements. Our developers are very experienced in the fields of electrooptical and electromechanical design, pyroelectric materials and signal processing electronics. This knowledge is the basis for developing innovative products as well as for the optimization of applied production technologies and further development of our extensive measurement techniques. We permanently increase our development workforce as the market is growing, in order to prepare for future request and to be able to react to the newest trends, such as the application of microsystem technologies (MOEMS). In addition to product developments for our customers, we also cooperate with different project partners and work on various promotion projects for future infrared sensor generations. Our knowhow is reflected in our products, such as the microspectrometer with integrated MOEMSbased FabryPérot filter, which is currently one of the competitionleading innovations. It has also been distinguished by the optical industry and has won numerous prizes. Test Capabilities The main idea of the Quality Function Deployment determines the conceptual design, construction and distribution of our pyroelectric detectors, which perfectly match the customer requirements. Full simulation capability of standard and customized detector performance data and design Standardized kit for customized products Incoming Test, Lot Acceptance Test, InProcess Test, Screening Final Test/performance testing ( % burnin test including leak test, % traceability by serial number for signal and noise testing) Test equipment coming up to the latest technologies, data processing and calibration standards A highly productive team of engineers is available to process customer inquiries regarding production and quality issues 7

8 Pyroelectric Detectors and their Applications How does a Pyroelectric Detector work? The key components of InfraTec s detectors are single crystalline lithium tantalate (LiTaO 3 ) elements formed like a very thin plate capacitor. Lithium tantalate is a pyroelectric crystal whose ends become oppositely charged when heated. The thin pyroelectric elements of InfraTec s detectors are coated with an appropriate black absorbing layer to enhance the absorption of the incident infrared radiation. The absorbed radiation energy changes the temperature of the thin active element thus charging the surface electrodes. Depending on the detector operating mode, the resulting current or voltage generated across the capacitance of the pyroelectric elements (ically 50 pf) is then converted into a useful signal. This signal is proportional to the temperature change and not to the absolute temperature. This is why pyroelectric detectors can only respond to modulated radiation. Even the extremely small amounts of charges generated by minimal increases in crystal temperature are protected reliably from external disturbances by a hermetically sealed transistor package. A lowleakage/lownoise preamplifier (JFET or OpAmp) and a Feedback/Gate resistor (ically 50 GΩ) are included for current or voltage mode operation, usually in the transistor package. It is important to note that a change in detector package temperature (only in the temperature ramp!) can produce false signals. A compensation element shielded from the IR radiation and connected in an antiparallel way suppresses this effect. Product Range Standard products Singlechannel for gas analysis, flame detection and radiometry TO8 or TO39 housing Thermal compensation JFET or CMOS amplifier Extended products Singlechannel for analytical instruments and spectroscopy High performance Fast response Metal black coating Multi color products (Pyromid ) Dual, three or quad channel for gas analysis and flame detection Cross talk <0. % JFET or CMOS amplifier Optionally with beamsplitter Variable color products (FPI) Spectrometer device for analytical and gas sensing instruments Electrostatic drive Resolving power λ/ λ up to 60 Three tuning ranges available 8

9 Pyroelectric Detectors and their Applications Typical Application Fields Nondispersive Infrared (NDIR) gas analysis Transmittance [%] CO2 NBP CO2highAOI[Z] NBP Reference [H] Wavelength [nm] 4600 Due to its inherent properties the pyroelectric detector produces a signal proportional to the incoming modulated IR radiation. A narrow bandpass (NBP) filter with a wavelength that matches the absorption wavelength of the target gas (e.g µm for CO 2 ) is integrated in the cap of this detector. If a fraction of the radiation in the optical path is absorbed by the present gas (for example CO 2 ), the detector signal will be attenuated accordingly. Often a dual channel detector with a reference NBP filter at a neutral wavelength where no coincidence with the gas absorption and no interference with humidity and other gases is present (for example 3.95 µm) is used for comparison to compensate for aging or drift effects (like pollution, temperature and IR source). Flame and fire detection A ical HC flame is emitting radiation between 4.0 µm and 4.6 µm with a flicker frequency of some Hz. The radiation of the flame can be detected by a single channel detector (for example LME335) with an integrated NBP (around 4.3 µm). To distinguish the flame from sun light and arc welding light often two additional single channel detectors with special NBP filters or a multi channel detector (LMM244) with different NBP filters are used. 9

10 Pyroelectric Detectors and their Applications Variety of analytical instruments For detection of radiation from deep UV to FIR (THz), Single and Multi channel Pyrometers Pyroelectric line array (DESY, Hamburg) Integrated in a spectrometer it is used to characterize synchrotron radiation in the THz frequency region (,000) µm IR Pyrometer (Heitronics, Wiesbaden) For contactless temperature measurement ( 3,000) C

11 New Products New Products LME336 2 LME352 4 LIM2 6 LIM253 8 LFP805 20

12 LME336# NEW pyroelectric detector Description: single channel; TO39 housing; medium chip size; thermal compensation; low Micro; OpAmp; current mode; feedback GOhm; ultra low power consumption, single supply HOUSING: PIN ASSIGNMENT: V Out Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Noise [µv/hz/2] 0 2 Frequency [Hz]

13 pyroelectric detector TEST CIRCUIT: V 3V C nf Out Vout R 470k OPA378 or OPA34 AD Gnd/Case PARAMETERS: Aperture size Element size / e Thermal time constant Feedback resistor Feedback capacitor Polarity Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} Acceleration response { Hz} 5.0 mm sq. 2.0x2.0 mm² lithiumtantalate with black layer 300ms GOhm ±20 % 0.2 pf ±0. pf negative signal by positive IR flux change min 85,000 V/W max 57 µv/(sqrt[hz]) 4.0E08 cm(sqrt[hz])/w 250 µv/g; g = 9.8 m/s² CMOS operational amplifier Operating supply voltage V Recommended supply voltage V Supply current {output load MOhm} Offset voltage {25 C; output load MOhm} Optimal output load Absolute output current max OpAmp V V = 3 V 30 µa V/2 ±% 330 kohm ma Operating / Storage temperature C Filter sizes Field of View min All InfraTec windows and filters are available (except KBr and CsI). Customized filters upon request. rectangular filters: (5.25 x 5.25) mm 0/0.05 mm circular filters: ø6.5 mm ±0. mm standard thickness: 0.50 mm 0.2/0. mm thickness range mm on request CaF2 or BaF2; 0.4 mm thick: 80 Silicon substrate; 0.5 mm thick: 90 max IR window InfraTec reserves the right to change these specifications at any time without notification. 3 New Products LME336#

14 LME352# NEW pyroelectric detector Description: single channel; TO39 housing; medium chip size; low Micro; OpAmp; current mode; feedback 5GOhm; ultra low power consumption, single supply HOUSING: PIN ASSIGNMENT: V Out Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Noise [µv/hz /2] 4 Frequency [Hz]

15 pyroelectric detector TEST CIRCUIT: V 3V C nf Out Vout R 470k OPA378 or POA34 AD Gnd/Case PARAMETERS: Aperture size Element size / e Thermal time constant Feedback resistor Feedback capacitor Polarity Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} Acceleration response { Hz} 5.0 mm sq. 2.0x2.0 mm² lithiumtantalate with black layer 300ms 5 GOhm ± % 0.2 pf ±0. pf negative signal by positive IR flux change min 7,000 V/W max 2 µv/(sqrt[hz]).5e08 cm(sqrt[hz])/w 50 µv/g; g = 9.8 m/s² CMOS operational amplifier Operating supply voltage V Recommended supply voltage V Supply current {output load MOhm} Offset voltage {25 C; output load MOhm} Optimal output load Absolute output current max OpAmp V V = 3 V 30 µa V/2 ±% 330 kohm ma Operating / Storage temperature C Filter sizes Field of View min All InfraTec windows and filters are available (except KBr and CsI). Customized filters upon request. rectangular filters: (5.25 x 5.25) mm 0/0.05 mm circular filters: ø6.5 mm ±0. mm standard thickness: 0.50 mm 0.2/0. mm thickness range mm on request CaF2 or BaF2; 0.4 mm thick: 80 Silicon substrate; 0.5 mm thick: 90 max IR window InfraTec reserves the right to change these specifications at any time without notification. 5 New Products LME352#

16 LIM2# NEW pyroelectric multispectral detector, small Description: dual channel; TO46 housing; small chip size; JFET; voltage mode; HOUSING: PIN ASSIGNMENT: Drain, 2 Source Channel Source2 Channel2 Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Frequency [Hz] Noise [nv/hz/2]

17 pyroelectric multispectral detector, small TEST CIRCUIT: Drain, 2 9V Source Channel C nf Vout Source2 MUX Channel2 OPA227, OP77 9V R2 R 47k R3 47k M Gnd/Case C2 nf PARAMETERS: Aperture size Element size / e Thermal time constant Electrical time constant Polarity ø3.3 mm, single channel.7x.5 mm².4x.0 mm² lithiumtantalate with black layer 50 ms 2s positive signal by positive IR flux change Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} min 600 V/W max 450 nv/(sqrt[hz]) 3.5E08 cm(sqrt[hz])/w Offset voltage {opt. Drain current =... µa} Drain source voltage max V 8 V Operating / Storage temperature C IR window Filter sizes Field of View min Combinations of all InfraTec standard narrow band pass filters are available. Customized filters upon request. rectangular filters: (2.0 x.5) 0/0.05 mm circular filters: not applicable standard thickness: 0.50 mm 0.2/0. mm Silicon substrate; 0.5 mm thick: 8 Note: If visible light can penetrate the glassmetal seal in the detector socket, a small signal caused by light leakage may occur. InfraTec reserves the right to change these specifications at any time without notification. 7 New Products LIM2#

18 LIM253# NEW pyroelectric multispectral detector, small Description: three channel; TO39 housing; small chip size; thermal compensation; JFET; voltage mode; HOUSING: PIN ASSIGNMENT: Drain, 2, 3 Source Channel Source2 Channel2 Source3 Channel3 Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Frequency [Hz] Noise [nv/hz/2]

19 pyroelectric multispectral detector, small TEST CIRCUIT: Drain, 2, 3 9V Source Channel C nf Vout Source2 Channel2 OPA227, OP77 Source3 Channel3 MUX 9V R3 R2 47k R 47k R4 47k M Gnd/Case C2 nf PARAMETERS: Aperture size Element size / e Thermal time constant Electrical time constant Polarity ø6.0 mm, single channel ø2.5 mm.3x.3 mm² lithiumtantalate with black layer 350 ms 2.5 s positive signal by positive IR flux change Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} min 340 V/W max 270 nv/(sqrt[hz]) 3.5E08 cm(sqrt[hz])/w Offset voltage {opt. Drain current =... µa} Drain source voltage max V 8 V Operating / Storage temperature C IR window Filter sizes Field of View min Combinations of InfraTec standard narrow band pass filters are available. Customized filters upon request Filter chips will be cut by InfraTec standard thickness: 0.50 mm 0.2/0. mm Silicon substrate; 0.5 mm thick: 55 Note: If visible light can penetrate the glassmetal seal in the detector socket, a small signal caused by light leakage may occur. InfraTec reserves the right to change these specifications at any time without notification! 9 New Products LIM253#

20 LFP805337# NEW pyroelectric detector with tunable FPF Description: variable color; TO8 housing; medium chip size; thermal compensation; low Micro; OpAmp; current mode; feedback GOhm; Pyroelectric IR detector with integrated ø.9 mm micromachined tunable FabryPérot filter. Tuning range µm, advanced transimpedance amplifier (TIA) for Hz to Hz modulation frequency range HOUSING: PIN ASSIGNMENT: V Out V Order Sorting Filter GND 30R Substrate 200p n Shield n VC pF 30R VC ref Case FPI WAVELENGTH RESPONSE: Transmission [%] 47V 5V 75 40V 30V 0V Wavelength [µm].5.0 CWL [µm] control voltage [V] 40 50

21 pyroelectric detector with tunable FPF TEST CIRCUIT: C 5V nf V Vout R Out 470k OPA227, OP77 VC2 Order Sorting Filter GND 5V nf 30R n 200p C3 220nF Shield n pF Substrate VC 30R VC in [ V] OPA 445 C5 VC ref Case R2 [ V] R3 C4 220nF 5V PARAMETERS: FabryPérot filter Filter Aperture size Mirror drive mechanism Center wavelength Vc = 0 V Guaranteed tuning range Spectral 50 % of transmission peak,2 FPF µm ø.9 mm electrostatic, nf load, <0.05 µa leakage current.5 µm 0.5/0.4 µm µm nm Spectral % of transmission peak,2 Control voltage Vc Vc 8.0 µm Max Allowable control voltage nm 50 V (max 70 V) (control 8.0 µm).0 V Filter Mechanical time constant2 3 2 ms ±25 65 nm CWL shift by gravity when turning upside down 2 Order sorting filter Out of band blocking UV to Pyroelectric detector min WBP 7 µm LME337 based e Element size / e Thermal time constant Feedback resistor Feedback capacitor Polarity 2.0x2.0 mm² lithiumtantalate with black layer 50 ms GOhm ±20 % 50 ff ± ff negative signal by positive IR flux change Voltage responsivity (rms) {400 C, Hz, 25 Vc = 0 V Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {400 C, Hz, Hz, 25 Vc = 0 V CMOS operational amplifier Supply voltage V VOperating supply voltage V / VRecommended supply voltage V / VSupply current {output load MOhm} Offset voltage {25 C; output load MOhm} Optimal output load Absolute output current,000 V/W max 75 µv/(sqrt[hz]) 3.0E06 cm(sqrt[hz])/w max max OpAmp2 6 V V / V V = 5 V; V = 5 V 50 µa 5 mv... 5 mv 330 kohm ±0.4 ma C max Operating / Storage temperature Spectral measurement conditions: FTIR (resolution 4/cm; cone angle ±6 ; AOI 0 ) 2 ical variation within the tuning range (see application note) 3 Limited by pullin effect, please refer to the individual measurement report InfraTec reserves the right to change these specifications at any time without notification. 2 New Products LFP805337#

22 Notes 22

23 Standard Products Standard Products LIE LIE LIE26 28 LIE36 30 LME LME36 34 LME LME LME35 40 LME LME50 44 LME55 46

24 LIE200# pyroelectric detector, small Description: single channel; TO8 housing; small chip size; JFET; current mode; feedback GOhm; HOUSING: PIN ASSIGNMENT: Feedback Drain Source Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Frequency [Hz] Noise [µv/hz /2] 24

25 LIE200# pyroelectric detector, small TEST CIRCUIT: R Drain C C2 nf 22µF Source Gnd/Case OPA227, OP77 R2 270k Vout 9V C3 nf PARAMETERS: Aperture size Element size / e Thermal time constant Feedback resistor Feedback capacitor Polarity ø2.3 mm.4x.0 mm² lithiumtantalate with black layer 50 ms GOhm ± % 470 ff ± ff negative signal by positive IR flux change Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} min,400 V/W max 5.0 µv/(sqrt[hz]) 5.5E07 cm(sqrt[hz])/w Offset voltage {opt. Drain current =... µa} Drain source voltage max V 8 V Operating / Storage temperature C Filter sizes Field of View min All InfraTec windows and filters are available (except KBr and CsI). Customized filters upon request. rectangular filters: (2.70 x 2.70) mm 0/0.05 mm circular filters: ø3.3 mm ±0. mm standard thickness: 0.40 mm ±0. mm CaF2 or BaF2; 0.4 mm thick: 40 Silicon substrate; 0.5 mm thick: 45 IR window InfraTec reserves the right to change these specifications at any time without notification. 25 Standard Products Feedback 9V k

26 LIE202# pyroelectric detector, small Description: single channel; TO8 housing; small chip size; JFET; voltage mode; HOUSING: PIN ASSIGNMENT: Drain Source Gnd Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Frequency [Hz] Noise [nv/hz/2]

27 LIE202# pyroelectric detector, small R k Drain nf Source C Gnd 9V C2 Vout R2 OPA227, OP77 47k 22µF 9V Case C3 nf PARAMETERS: Aperture size Element size / e Thermal time constant Electrical time constant Polarity ø2.3 mm.4x.0 mm² lithiumtantalate with black layer 50 ms 2s positive signal by positive IR flux change Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} min 900 V/W max 350 nv/(sqrt[hz]) 4.0E08 cm(sqrt[hz])/w Offset voltage {opt. Drain current =... µa} Drain source voltage max Potential of detector case V 8 V selectable potential between V to Ground {EMC requires lowimpedance coupling} Operating / Storage temperature C Filter sizes Field of View min All InfraTec windows and filters are available (except KBr and CsI). Customized filters upon request. rectangular filters: (2.70 x 2.70) mm 0/0.05 mm circular filters: ø3.3 mm ±0. mm standard thickness: 0.50 mm 0.2/0. mm thickness range mm on request CaF2 or BaF2; 0.4 mm thick: 40 Silicon substrate; 0.5 mm thick: 45 IR window Note: If visible light can penetrate the glassmetal seal in the detector socket, a small signal caused by light leakage may occur. InfraTec reserves the right to change these specifications at any time without notification. 27 Standard Products TEST CIRCUIT:

28 LIE26# pyroelectric detector, small Description: single channel; TO8 housing; small chip size; thermal compensation; JFET; voltage mode; HOUSING: PIN ASSIGNMENT: Drain Source Gnd Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Frequency [Hz] Noise [nv/hz/2]

29 LIE26# pyroelectric detector, small R k Drain nf Source Vout R2 C Gnd 9V C2 OPA227, OP77 47k 22µF 9V Case C3 nf PARAMETERS: Aperture size Element size / e Thermal time constant Electrical time constant Polarity ø2.3 mm.4x.0 mm² lithiumtantalate with black layer 50 ms 4s positive signal by positive IR flux change Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} min 450 V/W max 220 nv/(sqrt[hz]) 3.0E08 cm(sqrt[hz])/w Offset voltage {opt. Drain current =... µa} Drain source voltage max Potential of detector case V 8 V selectable potential between V to Ground {EMC requires lowimpedance coupling} Operating / Storage temperature C Filter sizes Field of View min All InfraTec windows and filters are available (except KBr and CsI). Customized filters upon request. rectangular filters: (2.70 x 2.70) mm 0/0.05 mm circular filters: ø3.3 mm ±0. mm standard thickness: 0.50 mm 0.2/0. mm thickness range mm on request CaF2 or BaF2; 0.4 mm thick: 40 Silicon substrate; 0.5 mm thick: 45 IR window Note: If visible light can penetrate the glassmetal seal in the detector socket, a small signal caused by light leakage may occur. InfraTec reserves the right to change these specifications at any time without notification. 29 Standard Products TEST CIRCUIT:

30 LIE36# pyroelectric detector Description: single channel; TO39 housing; medium chip size; thermal compensation; JFET; voltage mode; HOUSING: PIN ASSIGNMENT: Drain Source Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Frequency [Hz] Noise [nv/hz/2] 0 30

31 LIE36# pyroelectric detector TEST CIRCUIT: R Drain nf Source 9V C2 OPA227, OP77 R2 C Vout 47k 22µF 9V Gnd/Case C3 nf PARAMETERS: Aperture size Element size / e Thermal time constant Electrical time constant Polarity 5.0 mm sq. 2.0x2.0 mm² lithiumtantalate with black layer 50 ms 4s positive signal by positive IR flux change Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} min 50 V/W max 30 nv/(sqrt[hz]) 4.0E08 cm(sqrt[hz])/w Offset voltage {opt. Drain current =... µa} Drain source voltage max V 8 V Operating / Storage temperature C Filter sizes Field of View min All InfraTec windows and filters are available (except KBr and CsI). Customized filters upon request. rectangular filters: (5.25 x 5.25) mm 0/0.05 mm circular filters: ø6.5 mm ±0. mm standard thickness: 0.50 mm 0.2/0. mm thickness range mm on request CaF2 or BaF2; 0.4 mm thick: 65 Silicon substrate; 0.5 mm thick: 70 IR window InfraTec reserves the right to change these specifications at any time without notification. 3 Standard Products k

32 LME302# pyroelectric detector Description: single channel; TO39 housing; medium chip size; low Micro; JFET; voltage mode; HOUSING: PIN ASSIGNMENT: Drain Source Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Frequency [Hz] Noise [nv/hz/2] 0 32

33 LME302# pyroelectric detector TEST CIRCUIT: R Drain nf Source C C2 OPA227, OP77 R2 Vout 47k 22µF 9V Gnd/Case C3 nf PARAMETERS: Aperture size Element size / e Thermal time constant Electrical time constant Polarity Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} Acceleration response { Hz} 5.0 mm sq. 2.0x2.0 mm² lithiumtantalate with black layer 50 ms 5s positive signal by positive IR flux change min 340 V/W max 50 nv/(sqrt[hz]) 6.0E08 cm(sqrt[hz])/w 2 µv/g; g = 9.8 m/s² Offset voltage {opt. Drain current =... µa} Drain source voltage max V 8 V Operating / Storage temperature C Filter sizes Field of View min All InfraTec windows and filters are available (except KBr and CsI). Customized filters upon request. rectangular filters: (5.25 x 5.25) mm 0/0.05 mm circular filters: ø6.5 mm ±0. mm standard thickness: 0.50 mm 0.2/0. mm thickness range mm on request CaF2 or BaF2; 0.4 mm thick: 80 Silicon substrate; 0.5 mm thick: 90 IR window InfraTec reserves the right to change these specifications at any time without notification. 33 Standard Products 9V k

34 LME36# pyroelectric detector Description: single channel; TO39 housing; medium chip size; thermal compensation; low Micro; JFET; voltage mode; HOUSING: PIN ASSIGNMENT: Drain Source Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Frequency [Hz] Noise [nv/hz/2] 0 34

35 LME36# pyroelectric detector TEST CIRCUIT: R Drain nf Source C2 OPA227, OP77 R2 C Vout 47k 22µF 9V Gnd/Case C3 nf PARAMETERS: Aperture size Element size / e Thermal time constant Electrical time constant Polarity Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} Acceleration response { Hz} 5.0 mm sq. 2.0x2.0 mm² lithiumtantalate with black layer 50 ms 4s positive signal by positive IR flux change min 60 V/W max 30 nv/(sqrt[hz]) 4.0E08 cm(sqrt[hz])/w µv/g; g = 9.8 m/s² Offset voltage {opt. Drain current =... µa} Drain source voltage max V 8 V Operating / Storage temperature C Filter sizes Field of View min All InfraTec windows and filters are available (except KBr and CsI). Customized filters upon request. rectangular filters: (5.25 x 5.25) mm 0/0.05 mm circular filters: ø6.5 mm ±0. mm standard thickness: 0.50 mm 0.2/0. mm thickness range mm on request CaF2 or BaF2; 0.4 mm thick: 80 Silicon substrate; 0.5 mm thick: 90 IR window InfraTec reserves the right to change these specifications at any time without notification. 35 Standard Products 9V k

36 LME335# pyroelectric detector Description: single channel; TO39 housing; medium chip size; thermal compensation; low Micro; OpAmp; current mode; feedback GOhm; HOUSING: PIN ASSIGNMENT: V Out V Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Frequency [Hz] Noise [µv/hz /2] 0 36

37 LME335# pyroelectric detector TEST CIRCUIT: C nf V Out Vout OPA227, OP77 V 5V R 470k Gnd/Case C2 nf PARAMETERS: Aperture size Element size / e Thermal time constant Feedback resistor Feedback capacitor Polarity Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} Acceleration response { Hz} 5.0 mm sq. 2.0x2.0 mm² lithiumtantalate with black layer 50 ms GOhm ±20 % 0.2 pf ±0. pf negative signal by positive IR flux change min 85,000 V/W max 45 µv/(sqrt[hz]) 6.0E08 cm(sqrt[hz])/w 300 µv/g; g = 9.8 m/s² CMOS operational amplifier Supply voltage V VOperating supply voltage V / VRecommended supply voltage V / VSupply current {output load MOhm} Offset voltage {25 C; output load MOhm} Optimal output load Absolute output current max max OpAmp2 6 V V / V V = 5 V; V = 5 V 50 µa 5 mv... 5 mv 330 kohm ±0.4 ma Operating / Storage temperature C Filter sizes Field of View min All InfraTec windows and filters are available (except KBr and CsI). Customized filters upon request. rectangular filters: (5.25 x 5.25) mm 0/0.05 mm circular filters: ø6.5 mm ±0. mm standard thickness: 0.50 mm 0.2/0. mm thickness range mm on request CaF2 or BaF2; 0.4 mm thick: 80 Silicon substrate; 0.5 mm thick: 90 max IR window InfraTec reserves the right to change these specifications at any time without notification. 37 Standard Products 5V

38 LME336# NEW pyroelectric detector Description: single channel; TO39 housing; medium chip size; thermal compensation; low Micro; OpAmp; current mode; feedback GOhm; ultra low power consumption, single supply HOUSING: PIN ASSIGNMENT: V Out Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Noise [µv/hz/2] 0 38 Frequency [Hz]

39 LME336# pyroelectric detector V 3V C nf Out Vout R 470k OPA378 or OPA34 AD Gnd/Case PARAMETERS: Aperture size Element size / e Thermal time constant Feedback resistor Feedback capacitor Polarity Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} Acceleration response { Hz} 5.0 mm sq. 2.0x2.0 mm² lithiumtantalate with black layer 300ms GOhm ±20 % 0.2 pf ±0. pf negative signal by positive IR flux change min 85,000 V/W max 57 µv/(sqrt[hz]) 4.0E08 cm(sqrt[hz])/w 250 µv/g; g = 9.8 m/s² CMOS operational amplifier Operating supply voltage V Recommended supply voltage V Supply current {output load MOhm} Offset voltage {25 C; output load MOhm} Optimal output load Absolute output current max OpAmp V V = 3 V 30 µa V/2 ±% 330 kohm ma Operating / Storage temperature C Filter sizes Field of View min All InfraTec windows and filters are available (except KBr and CsI). Customized filters upon request. rectangular filters: (5.25 x 5.25) mm 0/0.05 mm circular filters: ø6.5 mm ±0. mm standard thickness: 0.50 mm 0.2/0. mm thickness range mm on request CaF2 or BaF2; 0.4 mm thick: 80 Silicon substrate; 0.5 mm thick: 90 max IR window InfraTec reserves the right to change these specifications at any time without notification. 39 Standard Products TEST CIRCUIT:

40 LME35# pyroelectric detector Description: single channel; TO39 housing; medium chip size; low Micro; OpAmp; current mode; feedback 5GOhm; HOUSING: PIN ASSIGNMENT: V Out V Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] 0. Frequency 0 [Hz] 00 Frequency 0 [Hz] 00 Noise [µv/hz /2] 0. 40

41 LME35# pyroelectric detector TEST CIRCUIT: C nf V Out Vout OPA227, OP77 V 5V R 470k Gnd/Case C2 nf PARAMETERS: Aperture size Element size / e Thermal time constant Feedback resistor Feedback capacitor Polarity Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} Acceleration response { Hz} 5.0 mm sq. 2.0x2.0 mm² lithiumtantalate with black layer 50 ms 5 GOhm ± % 0.2 pf ±0. pf negative signal by positive IR flux change min 7,000 V/W max µv/(sqrt[hz]).8e08 cm(sqrt[hz])/w 50 µv/g; g = 9.8 m/s² CMOS operational amplifier Supply voltage V VOperating supply voltage V / VRecommended supply voltage V / VSupply current {output load MOhm} Offset voltage {25 C; output load MOhm} Optimal output load Absolute output current max max OpAmp2 6 V V / V V = 5 V; V = 5 V 50 µa 5 mv... 5 mv 330 kohm ±0.4 ma Operating / Storage temperature C Filter sizes Field of View min All InfraTec windows and filters are available (except KBr and CsI). Customized filters upon request. rectangular filters: (5.25 x 5.25) mm 0/0.05 mm circular filters: ø6.5 mm ±0. mm standard thickness: 0.50 mm 0.2/0. mm thickness range mm on request CaF2 or BaF2; 0.4 mm thick: 80 Silicon substrate; 0.5 mm thick: 90 max IR window InfraTec reserves the right to change these specifications at any time without notification. 4 Standard Products 5V

42 LME352# NEW pyroelectric detector Description: single channel; TO39 housing; medium chip size; low Micro; OpAmp; current mode; feedback 5GOhm; ultra low power consumption, single supply HOUSING: PIN ASSIGNMENT: V Out Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Noise [µv/hz /2] 42 Frequency [Hz]

43 LME352# pyroelectric detector V 3V C nf Out Vout R 470k OPA378 or POA34 AD Gnd/Case PARAMETERS: Aperture size Element size / e Thermal time constant Feedback resistor Feedback capacitor Polarity Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} Acceleration response { Hz} 5.0 mm sq. 2.0x2.0 mm² lithiumtantalate with black layer 300ms 5 GOhm ± % 0.2 pf ±0. pf negative signal by positive IR flux change min 7,000 V/W max 2 µv/(sqrt[hz]).5e08 cm(sqrt[hz])/w 50 µv/g; g = 9.8 m/s² CMOS operational amplifier Operating supply voltage V Recommended supply voltage V Supply current {output load MOhm} Offset voltage {25 C; output load MOhm} Optimal output load Absolute output current max OpAmp V V = 3 V 30 µa V/2 ±% 330 kohm ma Operating / Storage temperature C Filter sizes Field of View min All InfraTec windows and filters are available (except KBr and CsI). Customized filters upon request. rectangular filters: (5.25 x 5.25) mm 0/0.05 mm circular filters: ø6.5 mm ±0. mm standard thickness: 0.50 mm 0.2/0. mm thickness range mm on request CaF2 or BaF2; 0.4 mm thick: 80 Silicon substrate; 0.5 mm thick: 90 max IR window InfraTec reserves the right to change these specifications at any time without notification. 43 Standard Products TEST CIRCUIT:

44 LME50# pyroelectric detector Description: single channel; TO39 housing; large chip size; low Micro; current mode; HOUSING: PIN ASSIGNMENT: Out Gnd Case FREQUENCY RESPONSE: relative Responsivity [%] 44 Frequency 0 [Hz] 00

45 LME50# pyroelectric detector TEST CIRCUIT: pf R Out C2 nf M Vout AD8627, OPA627 Gnd 5V Case C3 nf PARAMETERS: Aperture size Element size / e Thermal time constant Polarity 5.0 mm sq. 3.0x3.0 mm² lithiumtantalate with black layer 200 ms positive signal by positive IR flux change min.2 µa/w 20 pf max 0.00 Potential of detector case selectable potential between V to Ground {EMC requires lowimpedance coupling} Operating / Storage temperature C Filter sizes Field of View min All InfraTec windows and filters are available (except KBr and CsI). Customized filters upon request. rectangular filters: (5.25 x 5.25) mm 0/0.05 mm circular filters: ø6.5 mm ±0. mm standard thickness: 0.50 mm 0.2/0. mm thickness range mm on request CaF2 or BaF2; 0.4 mm thick: 60 Silicon substrate; 0.5 mm thick: 70 Current responsivity (rms) {500 K, Hz, 25 C, without filter/window} Element capacitance { khz, V, 25 C} Element dielectric loss { khz, V, 25 C} IR window InfraTec reserves the right to change these specifications at any time without notification. 45 Standard Products 5V C

46 LME55# pyroelectric detector Description: single channel; TO39 housing; large chip size; low Micro; OpAmp; current mode; feedback 5GOhm; HOUSING: PIN ASSIGNMENT: V Out V Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] 0. Frequency 0 [Hz] 00 Frequency 0 [Hz] 00 Noise [µv/hz /2] 0. 46

47 LME55# pyroelectric detector TEST CIRCUIT: C nf V Out Vout OPA227, OP77 V 5V R 470k Gnd/Case C2 nf PARAMETERS: Aperture size Element size / e Thermal time constant Feedback resistor Feedback capacitor Polarity Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} Acceleration response { Hz} 5.0 mm sq. 3.0x3.0 mm² lithiumtantalate with black layer 200 ms 5 GOhm ± % 0.2 pf ±0. pf negative signal by positive IR flux change min 6,500 V/W max 2 µv/(sqrt[hz]) 2.5E08 cm(sqrt[hz])/w 300 µv/g; g = 9.8 m/s² CMOS operational amplifier Supply voltage V VOperating supply voltage V / VRecommended supply voltage V / VSupply current {output load MOhm} Offset voltage {25 C; output load MOhm} Optimal output load Absolute output current max max OpAmp2 6 V V / V V = 5 V; V = 5 V 50 µa 5 mv... 5 mv 330 kohm ±0.4 ma Operating / Storage temperature C Filter sizes Field of View min All InfraTec windows and filters are available (except KBr and CsI). Customized filters upon request. rectangular filters: (5.25 x 5.25) mm 0/0.05 mm circular filters: ø6.5 mm ±0. mm standard thickness: 0.50 mm 0.2/0. mm thickness range mm on request CaF2 or BaF2; 0.4 mm thick: 60 Silicon substrate; 0.5 mm thick: 70 max IR window InfraTec reserves the right to change these specifications at any time without notification. 47 Standard Products 5V

48 Notes 48

49 Extended Products Extended Products LIE32 50 LIE32f 52 LIE332f 54

50 LIE32# high performance pyroelectric detector Description: single channel; TO39 housing; medium chip size; JFET; voltage mode; long time constant, metal black coating HOUSING: PIN ASSIGNMENT: Drain Source Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency 0 [Hz] 00 Noise [nv/hz/2] Frequency 0 [Hz] 00

51 LIE32# high performance pyroelectric detector TEST CIRCUIT: R k Drain nf Source C 9V C2 OPA227, OP77 R2 Vout 47k 22µF 9V Gnd/Case C3 PARAMETERS: Aperture size Element size / e Thermal time constant Electrical time constant Polarity ø5.0 mm ø2.0 mm lithiumtantalate with metal black layer 200 ms 5s positive signal by positive IR flux change min 500 V/W min 50 V/W max 80 nv/(sqrt[hz]) max 35 nv/(sqrt[hz]) 8.0E08 cm(sqrt[hz])/w 4.0E08 cm(sqrt[hz])/w.6e08 cm(sqrt[hz])/w Offset voltage {opt. Drain current =... µa} Drain source voltage max V 8 V Operating / Storage temperature C Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} Detectivity {500 K, khz, Hz, 25 C, without filter/window} IR window Filter sizes Field of View min All InfraTec standard crystal windows (BaF2, CaF2, CsI, KBr, Sapphire) are available. Customized filters upon request. rectangular filters: (5.25 x 5.25) mm 0/0.05 mm circular filters: ø6.5 mm ±0. mm standard thickness: 0.50 mm 0.2/0. mm max thickness: 0.85 mm CaF2 or BaF2; 0.4 mm thick: 90 InfraTec reserves the right to change these specifications at any time without notification. 5 Extended Products nf

52 LIE32f# high performance pyroelectric detector Description: single channel; TO39 housing; medium chip size; JFET; voltage mode; short time constant, metal black coating HOUSING: PIN ASSIGNMENT: Drain Source Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency 0 [Hz] 00 Frequency 0 [Hz] 00 Noise [nv/hz/2]

53 LIE32f# high performance pyroelectric detector TEST CIRCUIT: R k Drain nf Source C 9V C2 OPA227, OP77 R2 Vout 47k 22µF 9V Gnd/Case C3 PARAMETERS: Aperture size Element size / e Thermal time constant Electrical time constant Polarity ø5.0 mm ø2.0 mm lithiumtantalate with metal black layer 20 ms 2s positive signal by positive IR flux change min 50 V/W max 50 nv/(sqrt[hz]) 3.0E08 cm(sqrt[hz])/w.3e08 cm(sqrt[hz])/w Offset voltage {opt. Drain current =... µa} Drain source voltage max V 8 V Operating / Storage temperature C Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} Detectivity {500 K, khz, Hz, 25 C, without filter/window} IR window Filter sizes Field of View min All InfraTec standard crystal windows (BaF2, CaF2, CsI, KBr, Sapphire) are available. Customized filters upon request. rectangular filters: (5.25 x 5.25) mm 0/0.05 mm circular filters: ø6.5 mm ±0. mm standard thickness: 0.50 mm 0.2/0. mm max thickness: 0.85 mm CaF2 or BaF2; 0.4 mm thick: 90 InfraTec reserves the right to change these specifications at any time without notification. 53 Extended Products nf

54 LIE332f# high performance pyroelectric detector Description: single channel; TO39 housing; small chip size; JFET; voltage mode; short time constant, metal black coating HOUSING: PIN ASSIGNMENT: Drain Source Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency 0 [Hz] 00 Frequency 0 [Hz] 00 Noise [nv/hz/2]

55 LIE332f# high performance pyroelectric detector TEST CIRCUIT: R k Drain nf Source C 9V C2 OPA227, OP77 R2 Vout 47k 22µF 9V Gnd/Case C3 PARAMETERS: Aperture size Element size / e Thermal time constant Electrical time constant Polarity ø5.0 mm ø.3 mm lithiumtantalate with metal black layer 20 ms s positive signal by positive IR flux change min 20 V/W max 65 nv/(sqrt[hz]) 3.0E08 cm(sqrt[hz])/w.3e08 cm(sqrt[hz])/w Offset voltage {opt. Drain current =... µa} Drain source voltage max V 8 V Operating / Storage temperature C Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} Detectivity {500 K, khz, Hz, 25 C, without filter/window} IR window Filter sizes Field of View min All InfraTec standard crystal windows (BaF2, CaF2, CsI, KBr, Sapphire) are available. Customized filters upon request. rectangular filters: (5.25 x 5.25) mm 0/0.05 mm circular filters: ø6.5 mm ±0. mm standard thickness: 0.50 mm 0.2/0. mm max thickness: 0.85 mm CaF2 or BaF2; 0.4 mm thick: 85 InfraTec reserves the right to change these specifications at any time without notification. 55 Extended Products nf

56 Notes 56

57 Multi Color Products Multi Color Products LIM0 58 LIM LIM LIM2 64 LIM24 66 LIM LIM LIM LIM34 74 LMM244 76

58 LIM0# pyroelectric multispectral detector Description: quad channel; TO8 housing; small chip size; JFET; voltage mode; beamsplitter; HOUSING: PIN ASSIGNMENT: Drain Source Channel Drain2 Source2 Channel2 Drain3 Source3 Channel3 Drain4 Source4 Channel4 Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Frequency [Hz] Noise [nv/hz/2]

59 LIM0# pyroelectric multispectral detector TEST CIRCUIT: Drain 9V Source Channel C nf Drain2 Source2 Channel2 Drain3 Source3 Channel3 Vout Drain4 OPA227, OP77 Source4 Channel4 R3 47k 9V MUX R4 R2 47k R 47k R5 47k M Gnd/Case C2 nf Aperture size Element size / e Beamsplitter Thermal time constant Electrical time constant Polarity ø2.5 mm 2.2x.3 mm² lithiumtantalate with black layer array of micro pyramids 250 ms 5s positive signal by positive IR flux change Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} min 60 V/W max 200 nv/(sqrt[hz]) 8.0E07 cm(sqrt[hz])/w Offset voltage {opt. Drain current =... µa} Drain source voltage max V 8 V Operating / Storage temperature C IR window Filter sizes Aperture window Aperture window sizes Field of View min Combinations of all InfraTec standard narrow band pass filters are available. Customized filters upon request. rectangular filters: (2.700/0. x /0.)mm circular filters: not applicable standard thickness: 0.50 mm 0.2/0. mm Selected by manufacturer for best channel filter matching rectangular filters: (5.250/0.05 x 5.250/0.05)mm circular filters: ø6.5 mm ±0. mm standard thickness: 0.50 mm 0.2/0. mm Maximum angle of incidence shall be ±7 otherwise internal reflexions may modify the channel ratio! InfraTec reserves the right to change these specifications at any time without notification. 59 Multi Color Products PARAMETERS:

60 LIM032# pyroelectric multispectral detector Description: dual channel; TO39 housing; small chip size; JFET; voltage mode; beamsplitter; HOUSING: PIN ASSIGNMENT: Drain, 2 Source Channel Source2 Channel2 Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Frequency [Hz] Noise [nv/hz/2]

61 LIM032# pyroelectric multispectral detector TEST CIRCUIT: Drain, 2 9V Source Channel C nf Vout Source2 MUX Channel2 OPA227, OP77 9V R2 R 47k R3 47k M Gnd/Case C2 nf Aperture size Element size / e Beamsplitter Thermal time constant Electrical time constant Polarity 2.8 mm sq. 2.2x.3 mm² lithiumtantalate with black layer array of micro grooves 250 ms 5s positive signal by positive IR flux change Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} min 50 V/W max 220 nv/(sqrt[hz]) 2.9E08 cm(sqrt[hz])/w Offset voltage {opt. Drain current =... µa} Drain source voltage max V 8 V Operating / Storage temperature C IR window Filter sizes Aperture window Aperture window sizes Field of View min Combinations of all InfraTec standard narrow band pass filters are available. Customized filters upon request. rectangular filters: (2.700/0. x /0.)mm circular filters: not applicable standard thickness: 0.50 mm 0.2/0. mm Selected by manufacturer for best channel filter matching rectangular filters: (5.250/0.05 x 5.250/0.05)mm circular filters: ø6.5 mm ±0. mm standard thickness: 0.50 mm ±0. mm Maximum angle of incidence shall be ±7 otherwise internal reflexions may modify the channel ratio! InfraTec reserves the right to change these specifications at any time without notification. 6 Multi Color Products PARAMETERS:

62 LIM054# pyroelectric multispectral detector Description: quad channel; TO8 housing; small chip size; OpAmp; current mode; feedback 22GOhm; beamsplitter; HOUSING: PIN ASSIGNMENT: V Channel Out Out2 Channel2 Out3 Channel3 Channel4 Out4 VGnd Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Frequency [Hz] Noise [µv/hz /2] 62

63 LIM054# pyroelectric multispectral detector TEST CIRCUIT: V Channel 5V Out C nf Out2 Channel2 Out3 Channel3 Vout Channel4 Out4 MUX OPA227, OP77 VGnd Case 5V R4 R3 R2 R 470k 470k 470k R5 470k M C2 nf Aperture size Element size / e Beamsplitter Thermal time constant Feedback resistor Feedback capacitor Polarity Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} 2.8 mm sq. 2.2x.3 mm² lithiumtantalate with black layer array of micro pyramids 250 ms 22 GOhm ± % 0.2 pf ±0. pf negative signal by positive IR flux change min 3,000 V/W max 29 µv/(sqrt[hz]) 4.2E07 cm(sqrt[hz])/w CMOS operational amplifier Supply voltage V VOperating supply voltage V / VRecommended supply voltage V / VSupply current {output load MOhm} Offset voltage {25 C; output load MOhm} Optimal output load Absolute output current max max Potential of detector case Operating / Storage temperature max IR window Filter sizes Aperture window Aperture window sizes Field of View min OpAmp2 6 V V / V V = 5 V; V = 5 V 50 µa 5 mv... 5 mv 330 kohm ±0.4 ma selectable potential between V to Ground {EMC requires lowimpedance coupling} C Combinations of all InfraTec standard narrow band pass filters are available. Customized filters upon request. rectangular filters: (2.700/0. x /0.)mm circular filters: not applicable standard thickness: 0.50 mm 0.2/0. mm Selected by manufacturer for best channel filter matching rectangular filters: (5.250/0.05 x 5.250/0.05)mm circular filters: ø6.5 mm ±0. mm standard thickness: 0.50 mm 0.2/0. mm Maximum angle of incidence shall be ±7 otherwise internal reflexions may modify the channel ratio! InfraTec reserves the right to change these specifications at any time without notification. 63 Multi Color Products PARAMETERS:

64 LIM2# NEW pyroelectric multispectral detector, small Description: dual channel; TO46 housing; small chip size; JFET; voltage mode; HOUSING: PIN ASSIGNMENT: Drain, 2 Source Channel Source2 Channel2 Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Frequency [Hz] Noise [nv/hz/2]

65 LIM2# pyroelectric multispectral detector, small TEST CIRCUIT: Drain, 2 9V Source Channel C nf Vout Source2 MUX Channel2 OPA227, OP77 9V R2 R 47k R3 47k M Gnd/Case C2 nf Aperture size Element size / e Thermal time constant Electrical time constant Polarity ø3.3 mm, single channel.7x.5 mm².4x.0 mm² lithiumtantalate with black layer 50 ms 2s positive signal by positive IR flux change Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} min 600 V/W max 450 nv/(sqrt[hz]) 3.5E08 cm(sqrt[hz])/w Offset voltage {opt. Drain current =... µa} Drain source voltage max V 8 V Operating / Storage temperature C IR window Filter sizes Field of View min Combinations of all InfraTec standard narrow band pass filters are available. Customized filters upon request. rectangular filters: (2.0 x.5) 0/0.05 mm circular filters: not applicable standard thickness: 0.50 mm 0.2/0. mm Silicon substrate; 0.5 mm thick: 8 Note: If visible light can penetrate the glassmetal seal in the detector socket, a small signal caused by light leakage may occur. InfraTec reserves the right to change these specifications at any time without notification. 65 Multi Color Products PARAMETERS:

66 LIM24# pyroelectric multispectral detector Description: quad channel; TO8 housing; medium chip size; thermal compensation; JFET; voltage mode; HOUSING: PIN ASSIGNMENT: Drain Source Channel Drain2 Source2 Channel2 Drain3 Source3 Channel3 Drain4 Source4 Channel4 Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Frequency [Hz] Noise [nv/hz/2] 0 66

67 LIM24# pyroelectric multispectral detector TEST CIRCUIT: Drain 9V Source Channel C nf Drain2 Source2 Channel2 Drain3 Source3 Channel3 Vout Drain4 OPA227, OP77 Source4 Channel4 9V MUX R4 R3 47k R2 47k R 47k R5 47k M Gnd/Case C2 nf Aperture size Element size / e Thermal time constant Electrical time constant Polarity ø9.5 mm, single channel ø3.5 mm 2.0x2.0 mm² lithiumtantalate with black layer ms 4s positive signal by positive IR flux change Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} min 50 V/W max 20 nv/(sqrt[hz]) 4.5E08 cm(sqrt[hz])/w Offset voltage {opt. Drain current =... µa} Drain source voltage max V 8 V Operating / Storage temperature C IR window Filter sizes Field of View min Combinations of all InfraTec standard narrow band pass filters are available. Customized filters upon request. rectangular filters: (4.20 x 4.20) mm ±0. mm circular filters: not applicable standard thickness: 0.50 mm 0.2/0. mm thickness range mm on request CaF2 or BaF2; 0.4 mm thick: not applicable Silicon substrate; 0.5 mm thick: 40 InfraTec reserves the right to change these specifications at any time without notification. 67 Multi Color Products PARAMETERS:

68 LIM222# pyroelectric multispectral detector Description: dual channel; TO39 housing; small chip size; thermal compensation; JFET; voltage mode; HOUSING: PIN ASSIGNMENT: Drain, 2 Source Channel Source2 Channel2 Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Noise [nv/hz/2] 0 68 Frequency [Hz]

69 LIM222# pyroelectric multispectral detector TEST CIRCUIT: Drain, 2 9V Source Channel C nf Vout Source2 Channel2 MUX OPA227, OP77 9V R2 R 47k R3 47k M Gnd/Case C2 nf Aperture size Element size / e Thermal time constant Electrical time constant Polarity ø6.0 mm, single channel 2.7x.8 mm².0x.8 mm² lithiumtantalate with black layer ms 6s positive signal by positive IR flux change Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} min 280 V/W max 50 nv/(sqrt[hz]) 4.5E08 cm(sqrt[hz])/w Offset voltage {opt. Drain current =... µa} Drain source voltage max V 8 V Operating / Storage temperature C IR window Filter sizes Field of View min Combinations of all InfraTec standard narrow band pass filters are available. Customized filters upon request. rectangular filters: (3.50 ±0. x 2.50 ±0.)mm circular filters: not applicable standard thickness: 0.50 mm 0.2/0. mm thickness range mm on request CaF2 or BaF2; 0.4 mm thick: not applicable Silicon substrate; 0.5 mm thick: 20 InfraTec reserves the right to change these specifications at any time without notification. 69 Multi Color Products PARAMETERS:

70 LIM253# NEW pyroelectric multispectral detector, small Description: three channel; TO39 housing; small chip size; thermal compensation; JFET; voltage mode; HOUSING: PIN ASSIGNMENT: Drain, 2, 3 Source Channel Source2 Channel2 Source3 Channel3 Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Frequency [Hz] Noise [nv/hz/2]

71 LIM253# pyroelectric multispectral detector, small TEST CIRCUIT: Drain, 2, 3 9V Source Channel C nf Vout Source2 Channel2 OPA227, OP77 Source3 Channel3 MUX 9V R3 R2 47k R 47k R4 47k M Gnd/Case C2 nf Aperture size Element size / e Thermal time constant Electrical time constant Polarity ø6.0 mm, single channel ø2.5 mm.3x.3 mm² lithiumtantalate with black layer 350 ms 2.5 s positive signal by positive IR flux change Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} min 340 V/W max 270 nv/(sqrt[hz]) 3.5E08 cm(sqrt[hz])/w Offset voltage {opt. Drain current =... µa} Drain source voltage max V 8 V Operating / Storage temperature C IR window Filter sizes Field of View min Combinations of InfraTec standard narrow band pass filters are available. Customized filters upon request Filter chips will be cut by InfraTec standard thickness: 0.50 mm 0.2/0. mm Silicon substrate; 0.5 mm thick: 55 Note: If visible light can penetrate the glassmetal seal in the detector socket, a small signal caused by light leakage may occur. InfraTec reserves the right to change these specifications at any time without notification! 7 Multi Color Products PARAMETERS:

72 LIM262# pyroelectric multispectral detector Description: dual channel; TO39 housing; small chip size; thermal compensation; OpAmp; current mode; feedback GOhm; HOUSING: PIN ASSIGNMENT: V Channel Out Channel2 Out2 V Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Frequency [Hz] Noise [µv/hz/2] 72

73 LIM262# pyroelectric multispectral detector TEST CIRCUIT: V 5V Channel Out C nf Vout Channel2 Out2 MUX OPA227, OP77 V 5V R2 R 470k R3 470k M Gnd/Case C2 nf Aperture size Element size / e Thermal time constant Feedback resistor Feedback capacitor Polarity Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} ø6.0 mm, single channel 2.7x.8 mm².0x.8 mm² lithiumtantalate with black layer 50 ms GOhm ±20 % 0.2 pf ±0. pf negative signal by positive IR flux change min 60,000 V/W max 35 µv/(sqrt[hz]) 4.5E08 cm(sqrt[hz])/w CMOS operational amplifier Supply voltage V VOperating supply voltage V / VRecommended supply voltage V / VSupply current {output load MOhm} Offset voltage {25 C; output load MOhm} Optimal output load Absolute output current max max OpAmp2 6 V V / V V = 5 V; V = 5 V 50 µa 5 mv... 5 mv 330 kohm ±0.4 ma Operating / Storage temperature C max IR window Filter sizes Field of View min Combinations of all InfraTec standard narrow band pass filters are available. Customized filters upon request. rectangular filters: (3.50 ±0. x 2.50 ±0.)mm circular filters: not applicable standard thickness: 0.50 mm 0.2/0. mm thickness range mm on request CaF2 or BaF2; 0.4 mm thick: not applicable Silicon substrate; 0.5 mm thick: 30 InfraTec reserves the right to change these specifications at any time without notification. 73 Multi Color Products PARAMETERS:

74 LIM34# pyroelectric multispectral detector Description: quad channel; TO8 housing; medium chip size; thermal compensation; JFET; voltage mode; HOUSING: PIN ASSIGNMENT: Drain Source Channel Drain2 Source2 Channel2 Drain3 Source3 Channel3 Drain4 Source4 Channel4 Gnd/Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Frequency [Hz] Noise [nv/hz/2]

75 LIM34# pyroelectric multispectral detector TEST CIRCUIT: Drain 9V Source Channel C nf Drain2 Source2 Channel2 Drain3 Source3 Channel3 Drain4 Vout Source4 Channel4 OPA227, OP77 9V MUX R4 Gnd/Case R3 47k R2 47k R 47k R5 47k M C2 nf Aperture size Element size / e Thermal time constant Electrical time constant Polarity ø9.5 mm, single channel ø3.5 mm 2.0x2.0 mm² lithiumtantalate with black layer ms 2s positive signal by positive IR flux change Voltage responsivity (rms) {500 K, Hz, 25 C, without filter/window} Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {500 K, Hz, Hz, 25 C, without filter/window} min 300 V/W max 280 nv/(sqrt[hz]) 3.5E08 cm(sqrt[hz])/w Offset voltage {opt. Drain current =... µa} Drain source voltage max V 8 V Operating / Storage temperature C IR window Filter sizes Field of View min Combinations of all InfraTec standard narrow band pass filters are available. Customized filters upon request. rectangular filters: (4.20 x 4.20) mm ±0. mm circular filters: not applicable standard thickness: 0.50 mm 0.2/0. mm thickness range mm on request CaF2 or BaF2; 0.4 mm thick: not applicable Silicon substrate; 0.5 mm thick: 40 InfraTec reserves the right to change these specifications at any time without notification. 75 Multi Color Products PARAMETERS:

76 LMM244# pyroelectric multispectral detector Description: quad channel; TO8 housing; medium chip size; thermal compensation; low Micro; OpAmp; current mode; feedback GOhm; HOUSING: PIN ASSIGNMENT: V Channel Out Out2 Channel2 Out3 Channel3 Channel4 Out4 VGnd Case FREQUENCY RESPONSE: relative Responsivity [%] Frequency [Hz] Frequency [Hz] Noise [µv/hz/2] 0 76

77 LMM244# pyroelectric multispectral detector TEST CIRCUIT: V Channel 5V Out C nf Out2 Channel2 Out3 Channel3 Vout Channel4 Out4 MUX OPA227, OP77 VGnd Case 5V R4 R3 R2 R 470k 470k 470k R5 470k M C2 nf Aperture size Element size / e Thermal time constant Feedback resistor Feedback capacitor Polarity Voltage responsivity (rms) {500 K, 3 Hz, 25 C, without filter/window} Noise density (rms) {3 Hz, BW Hz, 25 C} Detectivity {500 K, 3 Hz, Hz, 25 C, without filter/window} Acceleration response { Hz} ø9.5 mm, single channel ø3.5 mm 2.0x2.0 mm² lithiumtantalate with black layer 50 ms GOhm ±20 % 0.2 pf ±0. pf negative signal by positive IR flux change min 90,000 V/W max 65 µv/(sqrt[hz]) 6.0E08 cm(sqrt[hz])/w 300 µv/g; g = 9.8 m/s² CMOS operational amplifier Supply voltage V VOperating supply voltage V / VRecommended supply voltage V / VSupply current {output load MOhm} Offset voltage {25 C; output load MOhm} Optimal output load Absolute output current max max Potential of detector case Operating / Storage temperature max IR window Filter sizes Field of View min OpAmp2 6 V V / V V = 5 V; V = 5 V 50 µa 5 mv... 5 mv 330 kohm ±0.4 ma selectable potential between V to Ground {EMC requires lowimpedance coupling} C Combinations of all InfraTec standard narrow band pass filters are available. Customized filters upon request. rectangular filters: (4.20 x 4.20) mm ±0. mm circular filters: not applicable standard thickness: 0.50 mm 0.2/0. mm thickness range mm on request CaF2 or BaF2; 0.4 mm thick: not applicable Silicon substrate; 0.5 mm thick: 50 InfraTec reserves the right to change these specifications at any time without notification. 77 Multi Color Products PARAMETERS:

78 Notes 78

79 Variable Color Products Variable Color Products LFP304L 80 LFP3950L 82 LFP805 84

80 LFP304L337# pyroelectric detector with tunable FPF Description: variable color; TO8 housing; medium chip size; thermal compensation; low Micro; OpAmp; current mode; feedback GOhm; Pyroelectric IR detector with integrated ø.9mm micromachined tunable FabryPérot filter. Tuning range µm, spectral bandwidth 80 nm, low spring stiffness, advanced transimpedance amplifier (TIA) for Hz to Hz modulation frequency range HOUSING: PIN ASSIGNMENT: V Out V Order Sorting Filter GND 30R 200p n Substrate Shield n VC pF 30R VC ref Case FPI WAVELENGTH RESPONSE: Transmission [%] 30V V 24V 9V 0V Wavelength [nm] CWL [nm] Control Voltage [V] 80 30

81 LFP304L337# pyroelectric detector with tunable FPF TEST CIRCUIT: C 5V nf V Vout R Out 470k OPA227, OP77 VC2 Order Sorting Filter GND 5V nf 30R n 200p C3 220nF Shield n pF Substrate VC 30R VC in [ V] OPA 445 C5 VC ref Case R2 [ V] R3 C4 220nF 5V PARAMETERS: FPF µm low spring stiffness design ø.9 mm electrostatic, nf load, <0.05 µa leakage current 4.3 µm 0.3/0.2 µm µm nm Spectral % of transmission peak,2 Control voltage Vc Vc 3.0 µm Max Allowable control voltage nm 30 V (max 33 V) (control 3.0 µm) 0.5 V Filter Mechanical time constant ms ± nm CWL shift by gravity when turning upside down 2 Order sorting filter Out of band blocking UV to Pyroelectric detector min WBP 25 µm LME337 based e Element size / e Thermal time constant Feedback resistor Feedback capacitor Polarity 2.0x2.0 mm² lithiumtantalate with black layer 50 ms GOhm ±20 % 50 ff ± ff negative signal by positive IR flux change Voltage responsivity (rms) {400 C, Hz, 25 Vc = 0 V Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {400 C, Hz, Hz, 25 Vc = 0 V CMOS operational amplifier Supply voltage V VOperating supply voltage V / VRecommended supply voltage V / VSupply current {output load MOhm} Offset voltage {25 C; output load MOhm} Optimal output load Absolute output current,700 V/W max 75 µv/(sqrt[hz]) 4.9E06 cm(sqrt[hz])/w max max OpAmp2 6 V V / V V = 5 V; V = 5 V 50 µa 5 mv... 5 mv 330 kohm ±0.4 ma C max Operating / Storage temperature Spectral measurement conditions: FTIR (resolution 4/cm; cone angle ±6 ; AOI 0 ) 2 ical variation within the tuning range (see application note) 3 Limited by pullin effect, please refer to the individual measurement report InfraTec reserves the right to change these specifications at any time without notification. 8 Variable Color Products FabryPérot filter Filter Aperture size Mirror drive mechanism Center wavelength Vc = 0 V Guaranteed tuning range Spectral 50 % of transmission peak,2

82 LFP3950L337# pyroelectric detector with tunable FPF Description: variable color; TO8 housing; medium chip size; thermal compensation; low Micro; OpAmp; current mode; feedback GOhm; Pyroelectric IR detector with integrated ø.9mm micromachined tunable FabryPérot filter. Tuning range µm, spectral bandwidth nm, low spring stiffness, advanced transimpedance amplifier (TIA) for Hz to Hz modulation frequency range HOUSING: PIN ASSIGNMENT: V Out V Order Sorting Filter GND 30R Substrate 200p n Shield n VC pF 30R VC ref Case FPI WAVELENGTH RESPONSE: Transmittance [%] 29V 75 26V 2.5V 0V 6V Wavelength [nm] CWL [nm] Control Voltage [V] 82 30

83 LFP3950L337# pyroelectric detector with tunable FPF TEST CIRCUIT: C 5V nf V Vout R Out 470k OPA227, OP77 VC2 Order Sorting Filter GND 5V nf 30R n 200p C3 220nF Shield n pF Substrate VC 30R VC in [ V] OPA 445 C5 VC ref Case R2 [ V] R3 C4 220nF 5V PARAMETERS: FPF µm low spring stiffness design ø.9 mm electrostatic, nf load, <0.05 µa leakage current 5.0 µm 0.3/0.2 µm µm nm Spectral % of transmission peak,2 Control voltage Vc Vc 3.9 µm Max Allowable control voltage nm 29 V (max 32 V) (control 3.9 µm) 0.5 V Filter Mechanical time constant2 35 ms ± nm CWL shift by gravity when turning upside down 2 Order sorting filter Out of band blocking UV to Pyroelectric detector min WBP 25 µm LME337 based e Element size / e Thermal time constant Feedback resistor Feedback capacitor Polarity 2.0x2.0 mm² lithiumtantalate with black layer 50 ms GOhm ±20 % 50 ff ± ff negative signal by positive IR flux change Voltage responsivity (rms) {400 C, Hz, 25 Vc = 0 V Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {400 C, Hz, Hz, 25 Vc = 0 V CMOS operational amplifier Supply voltage V VOperating supply voltage V / VRecommended supply voltage V / VSupply current {output load MOhm} Offset voltage {25 C; output load MOhm} Optimal output load Absolute output current, V/W max 75 µv/(sqrt[hz]) 3.5E06 cm(sqrt[hz])/w max max OpAmp2 6 V V / V V = 5 V; V = 5 V 50 µa 5 mv... 5 mv 330 kohm ±0.4 ma C max Operating / Storage temperature Spectral measurement conditions: FTIR (resolution 4/cm; cone angle ±6 ; AOI 0 ) 2 ical variation within the tuning range (see application note) 3 Limited by pullin effect, please refer to the individual measurement report InfraTec reserves the right to change these specifications at any time without notification. 83 Variable Color Products FabryPérot filter Filter Aperture size Mirror drive mechanism Center wavelength Vc = 0 V Guaranteed tuning range Spectral 50 % of transmission peak,2

84 LFP805337# NEW pyroelectric detector with tunable FPF Description: variable color; TO8 housing; medium chip size; thermal compensation; low Micro; OpAmp; current mode; feedback GOhm; Pyroelectric IR detector with integrated ø.9 mm micromachined tunable FabryPérot filter. Tuning range µm, advanced transimpedance amplifier (TIA) for Hz to Hz modulation frequency range HOUSING: PIN ASSIGNMENT: V Out V Order Sorting Filter GND 30R Substrate 200p n Shield n VC pF 30R VC ref Case FPI WAVELENGTH RESPONSE: Transmission [%] 47V 5V 75 40V 30V 0V Wavelength [µm].5.0 CWL [µm] control voltage [V] 40 50

85 LFP805337# pyroelectric detector with tunable FPF TEST CIRCUIT: C 5V nf V Vout R Out 470k OPA227, OP77 VC2 Order Sorting Filter GND 5V nf 30R n 200p C3 220nF Shield n pF Substrate VC 30R VC in [ V] OPA 445 C5 VC ref Case R2 [ V] R3 C4 220nF 5V PARAMETERS: FPF µm ø.9 mm electrostatic, nf load, <0.05 µa leakage current.5 µm 0.5/0.4 µm µm nm Spectral % of transmission peak,2 Control voltage Vc Vc 8.0 µm Max Allowable control voltage nm 50 V (max 70 V) (control 8.0 µm).0 V Filter Mechanical time constant2 3 2 ms ±25 65 nm CWL shift by gravity when turning upside down 2 Order sorting filter Out of band blocking UV to Pyroelectric detector min WBP 7 µm LME337 based e Element size / e Thermal time constant Feedback resistor Feedback capacitor Polarity 2.0x2.0 mm² lithiumtantalate with black layer 50 ms GOhm ±20 % 50 ff ± ff negative signal by positive IR flux change Voltage responsivity (rms) {400 C, Hz, 25 Vc = 0 V Noise density (rms) { Hz, BW Hz, 25 C} Detectivity {400 C, Hz, Hz, 25 Vc = 0 V CMOS operational amplifier Supply voltage V VOperating supply voltage V / VRecommended supply voltage V / VSupply current {output load MOhm} Offset voltage {25 C; output load MOhm} Optimal output load Absolute output current,000 V/W max 75 µv/(sqrt[hz]) 3.0E06 cm(sqrt[hz])/w max max OpAmp2 6 V V / V V = 5 V; V = 5 V 50 µa 5 mv... 5 mv 330 kohm ±0.4 ma C max Operating / Storage temperature Spectral measurement conditions: FTIR (resolution 4/cm; cone angle ±6 ; AOI 0 ) 2 ical variation within the tuning range (see application note) 3 Limited by pullin effect, please refer to the individual measurement report InfraTec reserves the right to change these specifications at any time without notification. 85 Variable Color Products FabryPérot filter Filter Aperture size Mirror drive mechanism Center wavelength Vc = 0 V Guaranteed tuning range Spectral 50 % of transmission peak,2

86 Notes 86

87 Description 88 Typical Filter Plots 95 Spectral Emission of IR Sources IR Filters and Windows IR Filters and Windows

88 IR Filters and Windows Description The detector window has to fulfill two functions:. Define the spectral sensitiveness of the pyroelectric chip according to the purpose of the application (between UV and far IR) Reliable seal of the optical interface between detector and environment Name Generation for Detectors The detector name will be determined by the detector e and the filter code according to the tables in chapters.2 to.4. The filters will be arranged in ascending order of the Center Wavelength (CWL). In dual channel detectors reference will always be placed in channel 2, in three and quad channel detectors reference will always be placed in channel. The additional aperture window in detectors with beamsplitter follows the filtercode with a dash. It is not advisable to use windows in multispectral detectors (except detectors with beamsplitter) and will not be offered by default. Not every filter can be built into every detector. Environment resistance and dimension play a decisive role. Please confirm your filter choice with InfraTec before ordering. Scheme of standard detector name: [Detector description][channel ]...[Channel x][aperture] Examples: Single channel Dual/Quad channel without beamsplitter Dual/Quad channel with beamsplitter LIE36 LIM262ZH / LMM244HDIL LIM032TH / LIM054HGEI Please confirm description with InfraTec before ordering. Customized detectors can consist of modified bodies and/or customized filters. The necessary dimensions of these filters are listed in the detector datasheet under the line filter sizes. Scheme of customized detector name: [Detector description][x###] InfraTec detectors are available with the following window versions: Standard crystal windows (chapter.2) Standard silicon windows (chapter.3) Standard narrow band pass filters (chapter.4) Customdesigned filters or filters provided by the customer (chapter.5) 88

89 IR Filters and Windows.2 Standard Crystal Windows Name Code Description Transmission Range Plot Page CaF2 0.4 mm thick 60 Calcium fluoride (UV 9) µm 95 CaF2 0.7 mm thick 6 Calcium fluoride (UV 8) µm 95 CaF2.0 mm thick 62 Calcium fluoride (UV 8) µm 95 BaF2 0.4 mm thick 63 Barium fluoride (UV 2) µm 95 BaF2.0 mm thick 64 Barium fluoride (UV 2) µm 95 CsI 0.8 mm thick 65 Cesium iodide, protected (UV 50) µm 96 KBr 0.8 mm thick 66 Potassium bromide, protected (UV 30) µm 96 KBr.0 mm thick 67 Potassium bromide, protected (UV 30) µm 96 Sapphire 0.4 mm thick 68 Sapphire uncoated (UV 5) µm 96 Sapphire 0.6 mm thick 69 Sapphire uncoated (UV 5) µm 96 Sapphire 0.6 mm thick 69S Sapphire uncoated, soldered (UV 5) µm Silicon uncoated (. 50) µm 96 Si uncoated 0.5 mm thick.3 Standard Silicon Windows Name Code Description Transmission Type Plot Page Si ARC (2 5) µm Coated silicon Antireflection 97 Si ARC (3 6) µm Coated silicon Antireflection 97 Si ARC (3 ) µm 2 Coated silicon Antireflection 97 Si WBP ( ) µm 3 Silicon WBP Bandpass 97 Si WBP ( ) µm 4 Silicon WBP Bandpass 97 Si LWP 5.3 µm 5 Silicon LWP Long wave pass 98 Si LWP 6.5 µm 6 Silicon LWP Long wave pass 98 Si LWP 7.3 µm 7 Silicon LWP Long wave pass IR Filters and Windows Surface quality: FF or better per MILF4866 Environment durability: acc. to MILF4866 (Temperature , Humidity , Moderate abrasion , Adhesion , Solubility and Cleanability )

90 IR Filters and Windows.4 Standard Narrow Bandpass (NBP) Filters NBP Filters are coated by default on germanium or silicon substrates. These filters feature is an excellent blocking in the shortwave (UV to NIR). Please note that an outofband transmission in the range > µm (long wave IR) is an always existing undesirable side effect and not shown in scans of this catalogue. Name [CWL/HPBW] Gas Code Tolerance of CWL [nm] Tolerance of HPBW [nm] Plot Page NBP 3.95 µm / 90 nm Reference H ±30 ±20 NBP 3.33 µm / 60 nm Methane CH4 C ±20 ±20 HC G ±30 ±20 flame F ±30 ±30 NBP 4.26 µm / 90 nm CO2 narrow CO2 T ±20 ±20 99 NBP 4.26 µm / 80 nm CO2 standard CO2 D ±20 ±20 99 NBP 4.27 µm / 70 nm CO2 high AOI CO2 Z ±30 ±20 99 NBP 4.45 µm / 60 nm CO2 long path CO2 E ±20 ±20 99 NBP 4.66 µm / 80 nm CO centered CO I ±40 ±20 99 NBP 4.74 µm / 40 nm CO flank CO K ±20 ±20 99 NBP 5.30 µm / 80 nm NOX NOX L ±40 ±20 NBP 7.30 µm / 200 nm SO2 SO2 U ±40 ±30 NBP 3.40 µm / 20 nm HC NBP 4.30 µm / 600 nm Flame Surface quality: FF or better per MILF4866 Environment durability: acc. to MILF4866 (Temperature , Humidity , Moderate abrasion , Adhesion , Solubility and Cleanability ) 90

91 IR Filters and Windows.5 Requirements for Customized Filters for use in InfraTec Detectors InfraTec offers their customers to build detectors with customized filters, there are two filter supply options:. 2. Customized Filter supplied by InfraTec with customized specification Customer Furnished Filter supplied by the customer directly Filters already cut to size are preferred. The correct size and tolerances for each detector e can be found in the datasheets ( Filter sizes ). Standard thickness for all filters is /0. mm. The thickness range of ( ) mm can be used for most of our detectors on request. Please confirm with InfraTec before ordering. Filter quantity required Production orders: Desired quantity % Sample orders under pcs: 23 additional filters Preferred packaging for the filters Waffle tray Wafer tape (blue tape foil) Filters provided must be clean without any ink point or other marking. Cleanliness is required for good adhesion and sealing of the filters to the pyroelectric detector package. InfraTec offers the option to assemble customer furnished filters supplied uncut in wafer format for production orders. Wafers can be cut for an additional charge. InfraTec cannot assume liability for peeling or chipping of filter layers or other problems that might occur during cutting. Please note that filters coated on germanium or hard substrates such as sapphire and quartz have an increased risk of damage during the cutting process. InfraTec limits the incoming inspection of customer furnished filters to a visual check and the identification of the Center Wavelength (CWL) and the Half Power Bandwidth (HPBW). The customer together with its filter supplier shall supervise the compliance of the filter specification. InfraTec has extensive experience in filter treatment. InfraTec cannot assume liability for any filter damage that may occur during processing. To achieve the complete success with the resulting detectors the course of action shall be cleared accurately between InfraTec and the customer. The customer s experience in the field of detector application and InfraTec s outstanding experience in detector design and production could than complement one another at a firm base. Please contact us in this case for more details. 9 IR Filters and Windows InfraTec has the following requirements for Customer Furnished Filter:

92 IR Filters and Windows.6 Field of View (FOV) A detector s Field of View (FOV) should be optimally chosen and specified in order to maximize useful incident radiation but also to minimize background or unwanted radiation. In other words, the FOV of a detector should be specified as large as necessary only to admit the maximum amount of useful radiation based on specific system characteristics and requirements. FOV AOI A high Angle of Incidence (AOI) shall be avoided for applications with narrowband IR filters (ical for NDIR gas analysis). In this case the physical conditioned shift of cuton and cutoff of the narrowband IR filter will move towards shorter wavelengths and will modify the desired spectral characteristics of the detector. In the following table FOV s for some of our standard detectors are listed. Additionally this information is given under the line Field of View in every detector datasheet: Group Standard Products Extended Products Multi Color Products Type LIE26 LIE36 LME302 LME335 LME55 LIE32 LIE332f LIM0 LIM032 LIM054 LIM24 LIM222 LIM262 LMM244 FOV for different window substrates Minimum value for every point of the sensitive element Calcium or Barium fluoride 0.4 mm thick not applicable not applicable not applicable not applicable not applicable not applicable not applicable 92 Silicon substrate Silicon substrate 0.5 mm thick.0 mm thick Maximum angle of incidence shall be ±7 otherwise internal reflections may modify the channel ratio!

93 IR Filters and Windows.7 Specification of Bandpass Filters Basic Parameters Peak Transmittance [%] Transmittance [%] % of Peak Transmittance [%] 40 HPBW [nm] 20 λ CWL [µm] 4.3 Wavelength [µm] λ2 4.5 The center wavelength CWL and the half power bandwidth HPBW define the working range of a bandpass filter. The HPBW is defined as the bandwidth between the halfpowerpoints (Wavelengths λ, λ2 at 50 % of Peak Transmittance). The center wavelength CWL is defined as the mean value of the two halfpowerpoints in terms of wavenumbers: CWL The Peak Transmittance is the maximum Transmission of the band and is specified as minimum value. For example, Peak Transmittance >/= 70 %. The filter should not have any transmittance outside of the used range, if possible. Shift of CWL A further specification of narrow bandpass filters is given by the shift of CWL dependent on. Angle of Incidence (AOI) 2. Temperature As a general rule, as temperature increases, IR bandpass filters will shift to longer wavelengths with some loss in band transmission. In addition, an angular shift generally results in a CWL shift to shorter wavelengths. 93 IR Filters and Windows Depending on the application InfraTec uses IR filters manufactured with a low angular shift design or a low TC (temperature coefficient) design. Most of our standard filters are special IR filter es with low angle shift. A higher temperature drift of the CWL will arise as a matter of principle for these filters. Furthermore, please note that multi channel detectors with AOI larger than ±5 degrees might cause interference problems between channels (cross talk). The spectral thermal shift and changes in transmission characteristics of coated filters, however, is determined by the materials and coating design used to manufacture such filters, and therefore vary by the e of filter (e.g. narrow band pass NBP, wide band pass WBP), wavelength region and filter manufacturer.

94 IR Filters and Windows Classification of InfraTec s standard filters in following design Low angular shift design C, E, F, I, K, L, T, U, Z Low TC design Angle 5 approximately 5 nm Temperature shift approximately 0.40 nm/k Angle 5 approximately 27 nm Temperature shift approximately 0.25 nm/k D, G, H Angle shift of NBP filter "CO2 standard" [D] Angle shift of NBP filter "CO2 high AOI" [Z] CO2 high AOI [Z] NBP 4.27µm/70nm CO2 standard [D] NBP 4.26µm/80nm Transmittance [%] Transmittance [%] Wavelength [nm] Temperature shift of NBP filter "CO2 standard" [D] Wavelength [nm] Temperature shift of NBP filter "CO2 high AOI" [Z] CO2 standard [D] NBP 4.26µm/80nm CO2 high AOI [Z] NBP 4.27µm/70nm C 60 Transmittance [%] Transmittance [%] C 40 5 C C Wavelength [nm] Wavelength [nm]

95 IR Filters and Windows 2 Typical Filer Plots 2. Standard Crystal Windows Calcium fluoride CaF2 0.4mm thick [60] Transmittance [%] 80 CaF2 0.7mm thick [6] CaF2.0mm thick [62] Wavelength [µm] Barium fluoride BaF2 0.4mm thick [63] BaF2.0mm thick [64] Wavelength [µm] IR Filters and Windows Transmittance [%] 80

96 IR Filters and Windows Sapphire uncoated Sapphire 0.4mm thick [68] Transmittance [%] 80 Sapphire 0.6mm thick [69] Wavelength [µm] Other substrates Transmittance [%] CsI 0.8mm thick [65] KBr 0.8mm thick [66] /.0mm thick [67] 20 Si uncoated 0.5mm thick [70] Wavelength [µm] 96

97 IR Filters and Windows 2.2 Standard Silicon Windows Coated silicon Si ARC 2 5µm [] Si ARC 3 6µm [] Transmittance [%] 80 Si ARC 3 µm [2] Wavelength [µm] Silicon WBP Si WBP µm [3] Si WBP µm [4] Wavelength [µm] 97 IR Filters and Windows Transmittance [%] 80

98 IR Filters and Windows Silicon LWP Si LWP 5.3µm [5] Transmittance [%] 80 Si LWP 6.5µm [6] Si LWP 7.3µm [7] Wavelength [µm]

99 IR Filters and Windows 2.3 Standard Narrow Band Pass Filter Band pass filter carbon dioxide NBP 4.27µm / 70nm CO2 high AOI [Z] Transmittance [%] 80 NBP 4.26µm / 90nm CO2 narrow [T] NBP 4.26µm / 80nm CO2 standard [D] 60 NBP 4.45µm / 60nm CO2 long path [E] Wavelength [µm] Band pass filter carbon monoxide NBP 4.66µm / 80nm CO [I] NBP 4.74µm / 40nm CO [K] Wavelength [µm] 99 IR Filters and Windows Transmittance [%] 80

100 IR Filters and Windows Band pass range ( ) μm NBP 3.33µm / 60nm Methane [C] Transmittance [%] 80 NBP 3.40µm / 20nm HC [G] NBP 3.95µm / 90nm Ref [H] Wavelength [µm] Band pass range ( ) μm NBP 4.30µm / 600nm Flame [F] Transmittance [%] 80 NBP 5.30µm / 80nm NOx [L] NBP 7.30µm / 200nm SO2 [U] Wavelength [µm] 7.5

101 IR Filters and Windows 3 Spectral Emission of IR Sources Spectral Emissive Power M [W/cm2µm] Spectral emissive power of a black body C (500K) 400 C C Wavelength [µm] Spectral emissive power (M) of a Black body: At 600 C M(4 µm) = 604 mw/cm²µm; M( µm) = 89.2 mw/cm²µm At 400 C M(4 µm) = 75 mw/cm²µm; M( µm) = 50 mw/cm²µm At 227 C M(4 µm) = 27.4 mw/cm²µm; M( µm) = 22.3 mw/cm² Spectral emissive power Electric light bulb 5V / ma (700 C) Spectral emissive power M [W/cm2µm] Spectral emissive power (M) of micro lamp for gas analyzing instrument: M(4 µm) =.65 mw/cm²µm M( µm) = 0 IR Filters and Windows Wavelength [µm]

102 Notes 2

103 Detector Basics Detector Basics τf ΦS AS Current Mode α /jωcfb HP tp Rfb GT T P TA /jωcp us heat sink Thermal Conversion 5 Thermal to Electrical Conversion 6 Electrical Conversion 7 Voltage Mode Current Mode 6 Infrared Sources 20 Low Noise Power Supply 2

104 Detector Basics The radiation sensitive key components of InfraTec s detectors are single crystalline lithium tantalate (LiTaO3) elements formed as a very thin plate capacitor. Lithium tantalate is a pyroelectric crystal whose ends become oppositely charged when heated. Although this unique effect was already known in the ancient world and was given the name pyroelectric in 824 by Brewster, the broad application in infrared detectors was introduced in the early 970s. Nowadays due to its simple but robust construction and its performance the pyroelectric detector is one of the most widelyused thermal infrared detectors. In figure the individual stages of the transformation from infrared radiation to an electrical signal is represented. Via a window or IR filter with a transmission rate F the radiation arrives at the pyroelectric element. The radiation flux S is absorbed and causes a change in temperature TP in the pyroelectric element. The thermal to electrical conversion is due to the pyroelectric effect by which the temperature change TP alters the charge density QP on the electrodes. An electrical conversion often follows in which, for example, an electrical signal us is created by a preamplifier or impedance converter. F S Fig : Thermal conversion TP Thermal to electrical conversion Conversion stages of the pyroelectric infrared detectors 4 Q P Electrical conversion u S

105 Detector Basics Detector Basics Thermal Conversion Within this chain thermal conversion is the basis for a high responsivity and a high signaltonoise ratio (often abbreviated SNR or S/N), through which a high temperature change TP is the objective. Figure 2 represents a simplified thermal model and in figure 3 the equivalent electrical circuit is depicted. The radiation sensitive element is characterized by the absorption rate, the heat capacity HP and the thermal conductance GT to its surroundings which is represented by a heat sink with a given temperature TA. F S AS HP heat sink Fig 2: Simplified thermal model Fig 3: TP the temperature difference results in HP GT () F S GT H P ~ ~ TP F S 2 GT T or for sinusoidal agitation in the steady state TP Equivalent electrical circuit T Using the thermal time constant /GT TA /j HP GT TP F S tp 2 2 (2) (3) For significant temperature differences to occur the product F has to be as near as possible to %. This can especially be achieved by the use of an absorption layer. The heat capacity value HP has to be low. For this the thickness tp of the radiationsensitive element has to be very low. Compromises are necessary as the required reduction in the thermal conductance GT is opposed by the increase of the thermal time con~ is the effective sinusoidal radiation flux. stant T. S 5

106 Detector Basics 2 Thermal to Electrical Conversion The thermal to electrical conversion is due to the pyroelectric effect, described by the pyroelectric coefficient p, and is proportional to the temperature rate TP and the detector s surface area As. TP dt ip pas (4) For sinusoidal agitation and considering equation (3) the result for the rms value (root mean square) of the pyroelectric short circuit current ip is as follows: ~ F S ~ ip pas 2 GT T (5) For the condition ( T ) 2 this equation changes to ~ ~ ~ F S F S F S p ~ ~ ip pa S pa S p F S GT T HP tpcp ' cp ' tp (6) being the volume specific heat capacitance. with Figure 4 represents the frequency dependence on the temperature change and the short circuit current of a ical pyroelectric detector at an incident radiation flux of µw. The frequency dependence on the temperature change shows the ical low pass characteristics. The corner frequency ft results from the thermal time constant T according to equation (7): ft (7) 2 T and has the value of Hz. Below the corner frequency the temperature change attains a saturation value of 53 µk. Above the corner frequency, the pyroelectric current, however, attains a saturation value of approximately 2.2 pa according to equation (6) Temperature change Pyroelectric current F= = S=µW GT=.95mW/K HP=3µWs/K T=59ms t P=25µm AS=4mm² cp=3.j/cm³/k p=7nc/cm²/k 0.00 Fig 4: ip [fa] 0 T P [µk] [Hz] Frequency 0 Frequency dependence on temperature change and short circuit current of a pyroelectric element 6

107 Detector Basics Detector Basics 3 Electrical Conversion 3. Responsivity The extremely low current, supplied by a highimpedance source has to be converted by a preamplifier with a highimpedance input. There are two alternatives available: voltage mode and current mode. The voltage mode can be implemented using a voltage follower and the current mode using a transimpedance amplifier (TIA) as seen in figure 5. Voltage Mode Current Mode /j Cfb Rfb /j CP Fig 5: us RG /j CP us Alternative preamplifier circuits The signal voltage us and the responsivity RV for both modes can be defined respectively using the same equation: ~ u~s F S AS p R / / 2 GT T E u~ RV ~S F AS p R / 2 2 / 2 GT 2 S E T where R RG E RG C P and is valid for the voltage mode R R fb E R fbc fb for the current mode. (8) (9) () () In voltage mode (VM) this can be simplified as follows for the condition that ( T ) 2 and ( E ) 2 RV F p c P ' p 0 AS Where ε0 is the dielectric constant and εr is the relative permittivity of the pyroelectric material. In current mode (CM) there are two ical cases. 7 (2)

108 Detector Basics For the first case that ( T ) and ( E ) is valid 2 2 Responsivity RV results as follows: RV F p c P ' t P C fb (3) p R fb cp ' t P (4) If ( T ) and ( E ) 2 2 is valid the responsivity RV is equal to: RV F Highmegohm resistors may be necessary for both current and voltage mode to achieve a high signal voltage and responsivity but the feedback capacitance Cfb is kept considerably lower than the capacitance of the pyroelectric chip CP. Therefore the electrical time constant E is significantly lower for the current mode and the signal voltage above the electrical corner frequency is much higher than for the voltage mode. Figure 6 illustrates the frequency dependence of both modes for ical detectors based on the results represented in figure Voltage Mode Current Mode ( E CM)² = ( T)² = us [mv] 00 ( E VM)² = 0 S=µW CP=62pF Cfb=0.68pF RG=Rfb=24G E VM=.5s E CM=6ms t T=50ms Fig 6: RV [V/W] Frequency [Hz] 0 Comparison of the frequency dependencies of signal voltage/responsivity for voltage and current mode 8

109 Detector Basics Detector Basics 3.2 Noise and specific detectivity The noise sources of the pyroelectric chip limit the detectable radiation flux or the signaltonoise ratio. Noise sources are: tan noise of the pyroelectric element Temperature noise Input noise voltage of the preamplifier Input noise current of the preamplifier Johnson noise of the highmegohm resistor As a measure of the signaltonoise ratio the specific detectivity is frequently used in conjunction with infrared detectors: D* Where u~n AS/ 2 RV u~n (5) is the effective noise value which is related to a noise bandwidth of Hz at the preamplifier out put (voltage noise density). In table the individual noise sources as well as the appendant noise voltage components are summarized. The quadratic superposition of the components results in the noise voltage density u~n. The frequency dependence and the resulting noise voltage density for a ical pyroelectric detector LME302, with the already utilized parameters, is portrayed in figure 7. ~ Components of the noise density u NX Noise sources u~nd (4kT CP tan P )/ 2 tan noise of the pyroelectric element R 2 2 AV (6) E Temperature noise R u~nt V (4kT 2GT ) / 2 (7) u~nv en AV (8) Voltage noise of the preamplifier u~ni in Current noise of the preamplifier R 2 2 AV (9) E 4kT u~nr R Johnson noise of the highmegohm resistor Table : Five essential noise sources (AV: voltage gain) 9 2 R 2 E 2 AV (20)

110 Detector Basics In an ideal pyroelectric detector the heat exchange due to radiation between the pyroelectric chip and its surroundings acts as the only unavoidable noise source. This temperature noise u~ NT determines the theo retically highest possible specific detectivity of a pyroelectric detector operated at room temperature: Dmax.8 cm Hz W (2) In a ical pyroelectric detector the other noise sources are considerably higher, shown in figure 7. The Johnson noise of the highmegohm resistor dominates at low frequencies (< Hz). At medium frequencies ( Hz), the tanδ noise of the pyroelectric element dominates the resultant noise density. At high frequencies (>,000 Hz), the voltage noise of the preamplifier specifies the resultant voltage noise density. 000 tanδ Noise 00 Temperature Noise Voltage Noise Noise [V/Hz /2] 0 Current Noise Johnson Noise Resultant Noise 0. Fig 7: 0 [Hz] Frequency 00 Frequency response of the resulting voltage noise density and of the various components of the voltage noise density of a ical pyroelectric detector (LME302)

111 Detector Basics Detector Basics 4 Voltage Mode 4. General information Due to its simplicity the voltage mode is the most commonly used operating mode for pyroelectric detectors. The following restrictions have to be considered regarding the layout of the amplifier and signal conditioning unit: The signal voltage of a pyroelectric voltage mode detector usually includes very lowfrequency parts (mhz) caused by /f characteristics. The cuton frequency of the amplifier s high pass should not be too low. The gate resistor (load resistor) should have a resistance of at least GOhm for high performance. The best solution for the protection of highimpedance components against humidity, which would cause current leakage, is the integration of these inside transistor style housing. Pyroelectric detectors should not be used without integrated impedance preamplifiers in high performance applications. The output signal of voltage mode detectors corresponds to the timeintegral of the IR radiation. This behavior suppresses fluctuations effectively. Sinusoidal signals, however, are phaseshifted by 90 by this electrical lowpass filter (f > ft). 4.2 Circuit diagram In the simplest case the preamplifier is formed as a JFET source follower. The gate resistor and the JFET are integrated into the detector housing. The resistor RS in the source line is placed outside the detector housing (see figure 8). The high signaltonoise ratio and the low temperature dependence, as well as the simplicity of the circuitry, are the reason for this widespread use. Without thermal compensation Fig 8: Parallel compensation Serial compensation Basic circuits for the voltage mode The gain A for these circuits results from the transconductance gfs of the JFET in the operating point and the source resistance RS: Av g fs RS g fs RS The demand for a high source resistance or a small drain current can be deduced from this. (22)

112 Detector Basics See below for an example equation for a gain of at least 0.8 (IDSS = saturation drain current): ID 0. I DSS (23) However the demand for a low output resistance limits the increase of the source resistance necessary for a gain near to the value of. The source resistance should not be over kohm at drain voltages up to 5 V. A constant current source can be used as an alternative as this possesses a very high inner resistance. Next to a gain value of approximately the temperature dependence of the transconductance is simultaneously suppressed and therefore the temperature stability of the gain is improved. See figure 9 for suggestions concerning the operation of the source follower. The JFET used by InfraTec represents a IDSS with a characteristic value of ma. The recommended drain current values for the operation of the detectors are between µa and µa. Remarks Output () Output (2) Output (3) Output (4) Fig 9: The simplest circuit High drain current and gain dependency on operating point Low dynamic Asymmetrical tuning Lower current and gain dependency on operating point as in () A greater tuning range than in (), symmetrical tuning possible Negative supply voltage Higher dynamic inner resistance Greater tuning range than in (), symmetrical tuning possible Negative supply voltage Lower temperature drift 2 active and 2 passive components Higher dynamic inner resistance Low noise Greater tuning range than in (), symmetrical tuning possible Negative supply voltage Greater temperature drift than in () Alternative lownoise drain current supplies for voltage mode detectors 2

113 Detector Basics Detector Basics For the design of the drain current supply circuitry please note the following: 4.3 The noise optimum for the JFET used in the InfraTec detector lies at 20 µa. Pyroelectric detectors generate a DC offset in temperature ramps, which defines the large signal behavior and can lead to significant changes in the gain of the source follower. Uncompensated standard detectors portray a positive offset shift. In comparison compensated detectors approximately portray a tenfold lower shift, which, dependent on the symmetry between the active and the compensating element, can be positive or negative. This occurring effect, taking place exclusively in the temperature ramps, can be minimized at the expense of a higher noise, using a lower electrical time constant (available for all es on demand). The available integrated current sources, for example the LM 34 from NSC, worsen the signaltonoise ratio or are expensive (REF200 from BurrBrown/TI). Wiring suggestions The electronic components shown in figures to 5 which are connected to the pyroelectric detector considerably determine noise and largesignal response. However, low cost OpAmps can be used due to the high signal level of pyroelectric detectors in contrast to thermopiles. The best results are achieved using lownoise amplifiers, which have been developed for high quality audio applications. Wiring for a low voltage supply preamplifier: Fig : Using TO8 detectors with electrically isolated housing (3.3 V Lithium battery supply; (0.4 33) Hz; gain 60 db) 3

114 Detector Basics T 40 a b Gain [db] Phase [deg] m m k k Frequency (Hz) Fig : Gain and phase of preamplifier as per figure vs. frequency a) b) Ip=2pA; fp=hz Time (s) Ip=2pA; fp=2hz 2.50 Uout (V) Uout (V) Uout (V) c) 3.00 Ip=2pA; fp=0.5hz Time (s) Fig 2: Uout of detector and preamplifier as per figure at different frequencies a) 0.5 Hz b) Hz c) 2 Hz (simulated) Wiring for a high precision preamplifier: Fig 3: Using dual channel detectors. (±5 V or higher; (0.3 22) Hz; gain db) Time (s)

115 Detector Basics Detector Basics a T 50 b Gain [db] Phase [deg] m m k k Frequency (Hz) Fig 4: Gain and phase of preamplifier as per figure 3 vs. frequency a) b) Ip=2pA; fp=hz m m Time (s) m Ip=2pA; fp=2hz.50 Uout (V) Uou (V).50 Uout (V) c) 2.00 Ip=2pA; fp=0.5hz Time (s) Fig 5: Uout of detector and preamplifier as per figure 3 at different frequencies a) 0.5 Hz b) Hz c) 2 Hz (simulated) Time (s)

116 Detector Basics 5 5. Current Mode General information Current mode pyroelectric detectors are not as widely available as voltage mode ones. The most probable reason for this being that elementary pyroelectric detectors are massproduced for light switches and motion detectors. Due to the complexity of the preamplifier circuit its use was limited to very few applications. At InfraTec we can supply a wide spectrum of current mode detectors which makes it less complicated to include detectors for gas and fire detection. 5.2 Circuit diagram Transistor style housing containing only the pyroelectric element. Transistor style housing containing the pyroelectric element, JFET and feedback resistor (an additional feedback capacitor of several picofarad (pf) is also possible). The integrated feedback capacitor prevents socalled gain peaking. Transistor style housing containing the pyroelectric element (also available with thermal compensation as LME335) and a complete current voltage converter with low input bias current OpAmp. Transistor style housing containing the pyroelectric element (also available with thermal compensation as LME336) and a complete current voltage converter with low input bias current OpAmp for single supply voltage (2.7 ) V. Fig 6: Four alternative pyroelectric detectors suitable for current mode 6

117 Detector Basics Detector Basics 5.3 Wiring suggestions The following examples are supposed to inspire one to consider the current mode as a reasonable alternative to the classic voltage mode based on the most modern available components. Fig 7: Circuit for current mode ((0.2 25) Hz; V/nA) of the pyroelectric detectors and LME50 Fig 8: Circuit for current mode of the pyroelectric detector LIE200 OpAmps with a low voltage noise should be used. Disadvantages of the circuitry depicted in figures 7 and 8 include: EMC (Electromagnetic Compatibility) problems due to parasitic capacities Permanent voltage offset across the pyroelectric element due to VGS (GateSource pinchoff voltage) of the JFET IGSS (= gate reverse leakage current) of the JFET determines the level and temperature dependence of the current noise These disadvantages can be avoided by integration of the OpAmp into the detector housing. Modern low power OpAmps with low current and voltage noise ensure the same signaltonoise ratio as in a simple JFET source follower, however due to the considerably lower electrical time constant a significantly higher responsivity can be achieved. The advantages of the integrated current mode detector are: 7

118 Detector Basics High responsivity (RV approximately 90,000 V/W) and high stability Very low output offset (< ±5 mv) Low electrical time constant, short warmup phase and fast recovery time No signal and detectivity loss when using the parallel compensation in thermal compensated detectors Following are two examples for simple application circuits using a current mode detector. Since the thermal and electrical time constant from the LME336 and LIM262 are in the same range the behavior of their detector output signal for different frequencies is comparable (see figure 20). Fig 9: Circuit for current mode (ical Rv 90,000 V/W) of the pyroelectric detector LME336 ( ) V a) b) 3.00 c) Ip= pa; fp= Hz Ip= pa; fp=20 Hz Ip= pa; fp=5 Hz Uout [V] Uout [V] Uout [V] Time (s) Time (s) Time (s) Fig 20: Signal voltage Uout of detector and preamplifier as per figure 9 at different frequencies a) Hz b) 5 Hz c) 20 Hz (simulated)

119 Detector Basics Detector Basics Fig 2: Circuit for current mode of the pyroelectric detectors LIM262 (ical Rv 60,000 V/W) 300 Gain (db) Phase [deg] m Frequency (Hz) Fig 22: Gain and phase of preamplifier as per figure 2 vs. frequency 9 k k

120 Detector Basics 6 Infrared Sources The application of a suitable IR source depends on the actual case of operation. Numerous sources with different emission characteristics are available. In the chapter Spectral Emission of IR Sources some spectra are described. For simple applications incandescent lamps can be used. For more demanding uses e.g. hot plates are applied. The operation of LED s is limited due to their narrow spectral emission range and temperature dependency. The radiation of the light sources always needs to be chopped. Common frequencies are between 0. and Hz. One possibility to realize this is the mechanical interruption of the radiation with a chopper wheel. An alternative is the electronic modulation/pulsing of the source (for example: lamp 6 V/5 ma T 6008 (MGG); hot plate 6.5 V/35 ma MIRL7900 (Intex) or IRLED). For the realization different circuits can be used. An incandescent lamp ically is chopped with a few Hz (up to Hz), the control circuit always needs to be adapted to the used lamp. The maximum chopper frequency for a hot plate source is in the range of up to Hz. The electronic drive of the IR source MIRL7900 with constant voltage driver is shown in figure 23. Fig 23: Example: Source MIRL7900 (Intex) with constant voltage driver An electronic drive independent of the supply voltage [V = (8... 8) V DC] can be realized with a constant current source. Figure 24 gives an example for this circuit with additional adjustment of the lamp currents for lighting and dark lighting. Fig 24: Example: Source MIRL7900 (Intex) with constant current driver 20

121 Detector Basics Detector Basics 7 Low Noise Power Supply Batteries (Alkaline, Silver oxidecell, Lithium cell) are a good choice for the detector supply as they have a very low ground noise. Generally linear dropout controllers can be used for the supply of both positive and negative voltage. Typical fixed controller IC s are to be seen in figure 25 and 26. Fig 25: L78L05 fixed 5 V and L79L05 fixed 5 V Fig 26: LT76ES5X (X=fixed voltage) and LT964ES55 fixed (5.0 V) For variable supply voltages the controllers LM37LZ (positive voltage) / LM337L (negative voltage) are a good choice. To achieve an adjustable output with declined proprietary current consumption LT76ES5BYP ( ) V (see figure 27) and LT964ES5BYP (.3 20) V can be used. We recommend to employ ceramic capacitors respectively solid tantalum capacitors with a small equivalent series resistance (ESR) and a low temperature coefficient. Fig 27: Variable power supply LT76ES5BYP for positive voltage Power supply for InfraTec CMOS OpAmp detectors For most InfraTec detectors a split power supply (± ±8) V is used. The new detectors with ultra low power consumption, e. g. LME336 or LME352, are equipped with a single supply OpAmp (2.7 ) V. For customized detectors InfraTec can also integrate different operational amplifiers. 2

122 Notes 22

123 Advanced Features Advanced Features Wide Bandpass filter spring suspension Vc movable reflector n d fixed reflector control electrodes pyroelectric detector Vsignal Pyroelectric Detectors with JFET source follower or integrated 24 CMOSOpAmp A Comparison Microphonic Effect in Pyroelectric Detectors 28 Beamsplitter Detectors Even for the narrowest signal beams 35 Basics and Application of Variable Color Products 37

124 Advanced Features Pyroelectric Detectors with JFET source follower or integrated CMOSOpAmp A Comparison In 2003 InfraTec added pyroelectric detectors with integrated CMOS Operational Amplifiers (OpAmp) to our established family of detectors with integrated Junction Field Effect Transistors (JFET). Advancements in analog silicon based technologies have allowed us to replace the classic JFET design with a more complex amplification circuit for nearly all applications. Well established JFET detector designs like the LME302, LME36 and LIM222 have been enhanced with CMOS OpAmps as in the LME35, LME335 and LIM262. LME36 with JFET (thermally compensated) LME335 with CMOS OpAmp (thermally compensated) Drain Source V Out V Ground= Case Ground=Case Voltage mode Fig : Current mode Examples of pyroelectric detectors with JFET (left side) and OpAmp (right side) Detectors with JFET and OpAmp are distinguished by more than orders of magnitude in signal voltage. The fundamental difference you find is in the analysis of the pyroelectric signal. As a result you will get different frequency responses of signal and noise (response and ical parameters in figure 2). 000 Voltage Mode Current Mode ( E CM )² = ( T )² = us [mv] 00 ( E VM )² = 0 S=µW CP=62pF Cfb=0.68pF RG=Rfb=24G E VM=.5s E CM=6ms T ms Fig 2: Frequency [Hz] RV [V/W] 0 Frequency response of signal voltage us and voltage responsivity RV of a pyroelectric detector with (2 x 2) mm active sensing element 24

125 In voltage mode the pyroelectric current, created in the single crystalline LiTaO3 chip, charges the electric capacity. The resulting voltage is displayed by a simple source follower (JFET, gate resistor and external source resistor). In current mode the generated pyroelectric current is transformed by a CurrentVoltageConverter (OpAmp with feedback components, also named TransImpedanceAmplifier TIA). The frequency dependent conversion factor I/U is determined by the complex feedback components and is ically in the range of ( ) pa/v. While the thermal time constant T (ically 50 ms) as a measure of the thermal coupling of the pyroelectric element to its surrounding is effective in both operation modes, the electric time constant E is determined by different components. In voltage mode E is calculated as a product of pyroelectric chip capacity CP and gate resistor RG (ically.5 s). In current mode E is only determined by the feedback components Rfb and Cfb (ically 6 ms). Main differences between pyroelectric detectors with JFET and CMOSOpAmp At common modulation frequencies between Hz and Hz in gas analysis and flame detection the detector will operate above the thermal and electrical time constant (/f behavior of signal). The maximal responsivity is located beyond the normal modulation frequency range. Lowfrequency disturbances up to some millihertz will be transmitted. Detectors need settling times up to some seconds. Detectors in current mode are mostly operated between both time constants and resultant cuton and cutoff frequency. Here the signal voltage is on its highest level and stable over a broad frequency range, possibly over some hundred Hertz. Lowfrequency disturbances are one magnitude away from the cuton frequency and will therefore by suppressed times more compared to the voltage mode. The measuring signals are already stable after a few seconds. Due to the virtual short circuit of the pyroelectric element in current mode, an antiparallel connected compensation element does not lead to a reduction of signal and detectivity. Furthermore an incomplete illuminated pyroelectric element in current mode does not cause a loss of both signal and detectivity in contrast to the voltage mode. Why we are using CMOSOperational amplifiers? CMOS technology combines technological and customer demands for a low supply voltage, low power consumption, RailtoRail performance at output and low chip costs. Additionally, the completely isolating gate (SiO2) in the operational amplifier shows a better performance during operation at high temperatures as opposed to the JFET design. The current mode, which earlier was only possible to apply in combination with very expensive OpAmps like OPA28 or AD549, can now be applied in applications for gas analysis and flame detection that were previously dominated both technologically and price wise by the JFET. Comparison of the modulated output signal for detectors with JFET and OpAmp The electrical time constant defines the form of the output signal in current and voltage mode. Identical time constants lead to the same signal form in both modes. In current mode we can work with a nearly arbitrary electrical time constant, which is an essential advantage. Therefore, short time constants are preferred due to the resulting short settling time. InfraTec can assure the availability of detectors with JFET source follower and CMOSOpAmp for many years to come. The technical advantages, however, will accelerate the trend to use the current mode OpAmp detectors. 25 Advanced Features Advanced Features

126 Advanced Features Figures 3 to 6 show ical signal characteristics in order with decreasing electrical time constant. Fig 3: LME302 Voltage mode at Hz, 5 Hz and 20 Hz, thermal time constant 50 ms, electrical time constant 5 s Fig 4: LME335 Current mode at Hz, 5 Hz and 20 Hz, thermal time constant 50 ms, electrical time constant 20 ms Fig 5: LME34 Current mode at Hz, 5 Hz and 20 Hz, thermal time constant 50 ms, electrical time constant 5 ms Fig 6: LME35 Current mode at Hz, 5 Hz and 20 Hz, thermal time constant 50 ms, electrical time constant ms 26

127 The resistance rating of the integrated feedback or gate resistor leads to different detector properties. For current mode detectors applies the following: A large feedback resistor results in a high signal and an increased detectivity since the noise only increases with the square root of the resistor value. In contrast an amplifier stage after the detector would increase signal and noise by the same ratio. A small resistor increases the stability of the DC operating point, therefore a thermal compensation is often not necessary for R< GOhm..0E9 LME335 GOhm LME GOhm LME35 5 GOhm Spec. Detectivity [cmhz/2/w] Responsivity [kv/w] 0 0. Fig 7:.0.0 Frequency [Hz].0E8 LME335 GOhm LME GOhm LME35 5 GOhm.0E Frequency [Hz].0 Frequency response of responsivity (signal) and specific detectivity (signaltonoise ratio) as a function of the feedback resistor in current mode detectors; LME335 ( GOhm), LME345 (24 GOhm), LME35 (5 GOhm) Voltage mode detectors behave as follows: The gate resistor value is not determining the signal height for frequencies above the thermal corner frequency around Hz. The noise is indirect proportional to the square root of the gate resistor value which results in a higher detectivity for detectors with a large gate resistor. A small resistor increases the stability of the DC operating point, therefore a thermal compensation is often not necessary for R< GOhm..0E9 Spec. Detectivity [cmhz/2/w] Responsivity [V/W] 00 0 LME302 5 GOhm LME GOhm LME GOhm 0. Fig 8:.0.0 Frequency [Hz].0E8.0E7 LME302 5 GOhm LME GOhm LME GOhm.0E Frequency [Hz].0 Frequency response of responsivity (signal) and specific detectivity (signaltonoise ratio) as a function of the gate resistor in voltage mode detectors; LME302 (standard 82 GOhm, for comparison with 22 and 5 GOhm) 27 Advanced Features Advanced Features

128 Advanced Features 2 Microphonic Effect in Pyroelectric Detectors 2. Basics All pyroelectric crystals are inherently piezoelectric. When a pyroelectric detector is mechanically excited through shock or vibration, an unwanted signal is produced. This behavior is called a microphonic effect or vibration response. The interaction of mechanical and electrical variables in piezoelectric crystals can be expressed in an opencircuit operation by a simplified equation for the electrical field strength E and its dependence on stress T as shown in table. Depending on the orientation of the stress, two basic effects can be distinguished: the Transverse Effect (along the chip edges) and the Longitudinal Effect (through the thickness). Transversal Effect Longitudinal Effect T E T E Model Opencircuit voltage Opencircuit voltage of a 30 µm thick LiTaO3 chip, 3 mm sq. element size, acceleration 9.8 m/s² (b=3 mm, h=30 µm, a= g) u vib d 3 bh ~ 0 T 33 2 a u vib 25 V u vib d 33 h 2 ~ a 0 T 33 2 uvib 0.8 V Table : Comparison of transverse and longitudinal effect on a square thin chip If the stress T is applied into the plane of the chip and transverse to the electric field strength E one can use the transversal model. The stress is a linear function in the X direction and exhibits its maximum value at the bearing point and zerocrossing at the right border. The mean stress is half of the maximum stress TXX. A lithium tantalate element with a square electrode of (3 x 3) mm and thickness of 30 µm would produce an opencircuit vibration voltage of about 25 µv at g (9.8 m/s²). If the acceleration acts longitudinal to the electrical field strength E and out of the plane of the chip the opencircuit vibration voltage per g is about 0.8 µv for a 30 µm thick lithium tantalate chip. This vibration voltage represents a limit for the reduction of the microphonic effect for a single element. Any further reduction could be achieved only by adding an antiparallel/antiserial compensating element. 28

129 Advanced Features Reduced microphonic voltage by inchipcompensation The simplest solution for reducing the stress caused by the transverse effect is the simultaneous clamping of the chip, both at the left and right borders. This results in tensile and compressive stress in the halves of the element and would counterbalance each other. A central fastening leads also to the compensation of stress. As shown in figure 9 the opencircuit vibration voltages are minimized by both the fastenings. Fig 9: Stress distribution on a doublesided (left), and center (right) clamped pyroelectric detector chip (3 x 3 x 0.03) mm3 with acceleration in the X direction The analytical description of the microphonic effect shows that the transverse effects are minimized by an outer symmetrical mounting, or a central mounting and that the longitudinal effect is much lower. However, stress overshoot around the mounting points is produced, when the acceleration is applied outofplane. In this case the simplified analytical description of the longitudinal effect does not provide proper results, since the chip structure and chip mounting varies significantly from the ideal configuration. In contrast to the ideal configuration, the arrangement and thickness of the electrodes is different. Furthermore, an additional absorption layer displaces the neutral stress line out of the center line. The influence of an acceleration outofplane could only be described accurately by a numerical analysis, for example by the simulation software ANSYS Multiphysics. As shown in figure, the base for the numerical analysis is a chip holder. The chip holder consists of a base plate with a central column surrounded by four symmetrically arranged columns. The pyroelectric chip is assembled on the chip holder by adhesive bonding. pyroelectric chip centrical column adhesive bonding outer column base plate Fig : Model of the assembly of chip holder and pyroelectric chip 29 Advanced Features 2.2

130 Advanced Features In the plane of the pyroelectric chip the opencircuit vibration voltage is compensated by the symmetrical arrangement of all columns. If we look at the outofchip plane, the opencircuit vibration voltage is compensated by the arrangement of the outer surrounding columns in such a manner that convex and concave warpings are induced by mechanical excitation in the normal direction. These warpings produce tensile and compressive stress at one surface and the reversed at the opposite side of the pyroelectric chip as illustrated in figure. The positive and negative piezoelectric charges generated by the stress are compensated by the electrodes, which cover the top and the bottom sides. To achieve a stress compensation, the chip deformation can be optimized by modifying the arrangements of the mountings (see figure 2). Fig : Deformation and stress of a quarter of a pyroelectric chip assembled on a chip holder using different support positions along the chip diagonal Vibration responsivity [µv/g] Radius edge to bearing [mm] 2 Fig 2: Acceleration response of the chip shown in figure as a function of the mounting point position The stress distribution inside of a pyroelectric chip is also affected by the chip coating, technological parameters, as well as the elastic modulus of the adhesive by which the pyroelectric chip is bonded onto the chip holder. Nevertheless, the statistics of sample measurements confirmed a good fitting of the test results and simulated values. 30

131 Advanced Features Microphonic effect at Voltage and Current mode operation The operational mode of a pyroelectric detector and the frequency range affects the result of piezoelectricity at detector s output (see figure 3). Voltage mode The Opencircuit operation of a pyroelectric chip as described in the earlier Detector Basics section is given ically in voltage mode for frequencies higher than 0.5 Hz. The criteria for this is the electrical break point set by the product of chip capacity CP ( ) pf and gate resistor RG (5... ) GOhm. In this frequency range the vibration or so called microphonic voltage at the detector output is identical with the opencircuit vibration voltage (see Detector Basics ): VM u vib u vib () A ical signal of a voltage mode detector is in the order of millivolts. A g acceleration (e.g. a shock) can produce a similar but disturbing signal of the mechanical vibration if its frequency fits the amplifier pass band. Cfb 5V Rfb Out V RG RS Out VGnd/Case Fig 3: Voltage mode operation (left) and current mode operation (right) of a pyroelectric detector Current mode Stateoftheart pyroelectric detectors make more and more use of the current mode (see figure 3). From the opencircuit vibration voltage uvib the shortcircuit current ivib is derived, which increases in a linear manner with the frequency. The shortcircuit current flows in a preamplifier and generates a signal voltage u at the output: ivib R fb uvibcm ( ) 2 / 2 (2) E As in voltage mode operation the microphonic voltage at detector s output is constant for frequencies well above the electrical cutoff frequency. Because the electrical time constant in current mode is defined by the feed back components Cfb and Rfb (this time constant is clearly shorter) this frequency range starts only from some Hz. In this frequency range the vibration voltage at the detector output is created by the opencircuit 3 Advanced Features 2.3

132 Advanced Features vibration voltage but amplified by the quotient of the capacitance of the pyroelectric chip and of the feedback capacitance: CM u vib C P C fb u vib (3) Comparison signal voltage VM vibration noise voltage VM signal voltage CM vibration noise voltage CM signal / vibration noise voltage u' [mv] ( T)² = ( E CM)² = ( E VM)² = 0. S = µw Cfb = 2.2 pf CP = 4 pf E CM = ms E VM = 0.6 s T = 59 ms R = 5 G AS= 9 mm² dp = 30 µm a = 9.8 m/s² Frequency [Hz] 0 00 Fig 4: Comparison of the signal voltage u S and of the vibration interference voltage u vib z (longitudinal effect) in voltage mode and current mode Figure 4 shows the frequency correlations with straight lines for the vibration voltage and dashed lines for signal voltage. The results are indicated with circles and squares for the current mode and the voltage mode respectively. Even if the vibration voltage behaves differently for current and voltage mode the ratio of signal to vibration voltage at a specific frequency (means the distance between the two red or the two blue lines in the diagram) is the same for current and voltage mode. There is no advantage from point of vibration responsivity by using current or voltage mode. 32

133 Advanced Features 2.4 Introduction of the term MicrophonicEquivalent Power (MEP) MEP Rvib RV (4) with u Rvib ~vib a (5) The MEP is defined as the quotient of the vibration responsivity and voltage responsivity and indicates the incident radiation flux, required to generate an equivalent rootmeansquare (rms) signal voltage for a given vibration. It is expressed in the units of W/g (gravitational acceleration g = 9.8 m/s²). Table 2 summarizes vibration responsivity, voltage responsivity and MEP. Of course the MEP is more or less independent from the operation mode of the preamplifier. In the case of a standard detector, the vibration responsivity and hence the MEP strongly depend on the spatial direction of the applied vibration. In the case of microphonic reduced detectors ( low micro e) with the novel chip holder, it is clearly demonstrated that the MEP value can be reduced to about (3 2) Hz in all three spatial directions. Detector LIE502 (VM) LIE500 (CM) LME502 (VM) LME500 (CM) Vibration Responsivity Rvib ( Hz, 25 C) in µv/g x y z 6,6 3, ,5 0,5 0, Voltage Responsivity Rv (500 K, Hz, 25 C) in V/W without window Microphonic Equivalent Power MEP ( Hz, 25 C) in nw/g x y z Table 2: Vibration responsivity, voltage responsivity and microphonicequivalent power of standard and low micro detectors Conclusion There are four ways to reduce the influence of the piezoelectric behavior on pyroelectric detectors in customer s sensor modules: Suppress mechanical vibrations as much as possible by pulse damper (smooth rubber, flexible cables). Please note that the elongation [mm] at a constant acceleration [m/s²] is frequency dependent. A sinusoidal acceleration of g = 9.8 m/s² is the result of a peaktopeak elongation of: 70 cm at Hz 7 mm at Hz 70 µm at Hz 0.7 µm at khz In a compact sensor module mechanical damping can only be realized for frequencies higher than Hz. 33 Advanced Features InfraTec introduced the MicrophonicEquivalent Power (MEP) for a simplified discussion:

134 Advanced Features Limit the electrical pass band of the amplifier stages especially at the high frequency side by a steep low pass. Compensation of the microphonic voltage by sophisticated mounting of the pyroelectric chip. InfraTec offers a variety of pyroelectric detectors in voltage mode (VM) or current mode (CM) operation with a reduced vibration response (so called low micro ) based on InfraTec s patented chip mounting technology. The reduction of the microphonic voltage is in the order of a twentieth (5 %) of a conventional pyroelectric detector. Figure 5 shows their ical frequency response. Please note that the differing vibration voltage of the CMOS OpAmp detector series LME35, 34 and 335 caused on a differing gain. LME335 offers the highest responsivity (90,000 Hz). Vibration Responsivity [µv/g] 0 LME335 LME34 LME35 LIE502 LME502 0, Frequency [Hz] 0 Fig 5: Test results of microphonic effect LME502 (VM, (3 x 3) mm2, low micro ), LIE502 (VM, (3 x 3) mm2, conventional), LME35 (CM, (2 x 2) mm2, low micro, 5 GΩ // 0.2 pf), LME34 (CM, (2 x 2) mm2, low micro, 24 GΩ // 0.2 pf), InfraTec s low micro technology is available for single element detectors such as LME36 (VM) or LME345 (CM) and multi color detectors such as LMM244 with an element size of (2 x 2) or (3 x 3) mm². These detectors can be identified at the part description by an M in the second digit (LME instead of LIE or LMM instead of LIM). 34

135 Advanced Features Beamsplitter Detectors Even for the narrowest signal beams The construction of multi color detectors with integrated beamsplitter is shown in the following picture. The IR radiation entering through the aperture is divided by a beamsplitter in two or four parts (4 channel pictured). Each of the partial beams goes through an IR filter and finally hits a pyroelectric detector chip. This design works well with single narrowbeam sources or in situations where contamination (dust, insects) in the light path could be an issue. Radiation Infrared Filter Detector Chip Beamsplitter Array Fig 6: Principle of reflective beamsplittering 3. Fig 7: 3D Design LIM054 General design The beamsplitters are made of gold plated microstructures for the two and four channel devices to achieve a homogeneous distribution of the radiance. The filters are mounted at a certain angle to obtain a normal incidence of the radiation. This configuration avoids drifts in the filter transmission curves to shorter wavelengths and the influence of the opposite filter (reflections). In addition to four channel beamsplitter detectors using foursided micro pyramids, InfraTec has also developed two channel detectors based on micro Vgrooves. In the following figure SEM images of two and four channel beamsplitters are shown. The Vgroves pitch is µm and the pyramids are 50 µm, with the tilt angle of the filters and detectors set at Advanced Features 3

136 Advanced Features Fig 8: Micro groove (2channel) 3.2 Fig 9: Micro pyramids (4channel) Comparison to other multi channel detectors The beamsplitter detector has a single aperture compared to conventional multi channel detectors. It is possible to use a gas cell with a smaller diameter reducing the gas volume. A smaller gas volume reduces the size of the sensor module and accelerates the gas exchange. Also, the signal ratio of all channels is independent from aging, mechanical shift or pollution processes among one another. The multi color detectors should be used for the analysis of gas mixtures with few known gases. Typical examples for a successful application are anesthetic gas monitors and the pulmonary function testing. Variable color detectors as described in the following allow a more flexible operation of the analyzer enabling the detection of adjoining or overlapping absorption bands. So far the measurement of single gases like ethanol and carbon dioxide as well as gas mixtures of methane, propane and anesthetic gases have been tested. In the following table characteristics of the multi and variable color detectors are summarized. Detector Specification Principal Filtering Area to be illuminated Spectral Range Current Mode (available) Voltage Mode (available) Thermal Compensation Multi Color Individual Windows Parallel Ø 9.5 mm (2 25) µm Yes Yes Yes 36 Multi Color Variable Color Beamsplitter Tunable FabryPérot Filter Parallel Serial Ø 2.5 mm Ø.9 mm (3.0 4.) µm (2 25) µm ( ) µm (8.0.) µm Yes Yes Yes No No Yes

137 Advanced Features Basics and Application of Variable Color Products 0B The key element of InfraTec s variable color products is a silicon micro machined tunable narrow bandpass filter, which is fully integrated inside the detector housing. Applying a control voltage to the filter allows it to freely select the wavelength within a certain spectral range or to sequentially measure a continuous spectrum. This design is very different from detectors with fixed filter characteristics and enables the customer to realize a low resolving and low cost spectrometer. The variable color product group currently includes the LFP304L337 LFP3950L337 LFP which differ in the wavelength range they each cover. The pyroelectric detector used is similar to the standard LME335 device, but with a shorter electrical time constant. New es and wavelength ranges may be introduced in the future. 4. FabryPérot filter (FPF) B The tunable filter is based on the wellknown FabryPérot Interferometer (FPI). Two flat and partially transmitting mirrors, characterized by reflectance R and absorptance A, are arranged in parallel at a distance d, forming an optical resonator with the refractive index n (figure 20 left). The beam with intensity I0, incident under the angle β, is reflected back and forth inside the resonator. Multiplebeam interference generates a pattern of successive peaks in the transmittance spectrum T( ) of the FPF (figure 20 right), described by the Airy formula T It I0 Tmax 2 π n d cos F sin 2 (6) with the peak transmittance A Tmax R 2 (7) and the finesse factor F 4R (8) R 2 37 Advanced Features 4

138 Advanced Features Fig 20: Schematic configuration and transmittance function of the FabryPérot Interferometer The transmittance peaks of different interference orders m are located at wavelengths, for which the resonance condition m 2 n d cos m (9) is met. The FPI can be used as a tunable narrowband filter, if the desired order is selected by means of an additional broad bandpass filter (order sorting filter, blocking filter) and if the resonator gap d can be adjusted to tune the transmitted wavelength λm within the given free spectral range FSR for this order. The characteristic filter parameters of an FPF can be derived from the previous equations. In all es, that are currently available from InfraTec, the first interference order is used (m = ). Given that n = (air inside the gap) and β = 0 (normal incidence), the equations can be further simplified. The center wavelength CWL is defined as the mean value of the two halfpowerpoints (T50) in terms of wavenumbers: CWL () (Because of the periodicity of the Airy formula (eq. 6) in wavenumbers, calculation of the CWL in the wavenumber domain is preferred over wavelengths. In general, calculation of the CWL of interference filters in the wavenumber or wavelength domain are both common). The halfpower bandwidth HPBW is the decisive factor for the spectral resolution: HPBW 2 d R π R () The ratio of FSR and HPBW (calculated in terms of wavenumbers) is called the finesse ~ F. In the theoretical ideal case (perfectly flat, smooth and parallel mirrors, collimated beam) it depends only on the reflectance R (reflectance finesse F~R ) FSR π R π F ~ FR HPBW R 2 (2) In practice the finesse is limited by imperfections of the mirrors and the angle distribution of the transmitted beam. 38

139 Advanced Features Variable Color detector 2B InfraTec s FP filters are fabricated with silicon bulk micromachining technology and wafer bonding. Bragg reflectors for the specific wavelength ranges are coated on thick silicon carriers to guarantee a high finesse. The back sides are antireflection coated. The fixed bottom carrier is equipped with control electrodes, whereas the upper reflector is suspended by springs (figure 2). Applying a voltage Vc to the electrodes creates an electrostatic force, which decreases the resonator gap d and, consequently, tunes the filter wavelength. Fig 2: Schematic configuration (left) and picture (right) of the variable color detector The MOEMS FPF is integrated in a TO8 housing together with a pyroelectric detector (figure 2). The latter is a state of the art thermally compensated currentmode e, similar to LME335 but with smaller feedback capacitance. This results in a flat frequency response up to several tens of Hz. The thermal time constant is in the range of 50 ms. The element size of (2 x 2) mm2 matches the size of the filter aperture (Ø.9 mm). The broad band pass blocking filter is integrated in the cap. The mirrors of the FPI are made from dielectric layer stacks (Bragg reflectors) with a limited width of the reflective band (stop band). Therefore, the usable tuning range in the first order is less than expected from the theoretical FSR. Besides this, the reflectance and, consequently, the finesse vary over the tuning range ( F~R 40 80). Tuning the CWL therefore results in a variation of the HPBW and the peak transmittance within certain limits. Figure 22 shows the ical variation of the HPBW and the limits given by fabrication tolerances. HPBWmin corresponds to the center and HPBWmax to the upper end of the tuning range. Filter code HPBWmin HPBWmax Tolerance range 304L 68 nm 85 nm nm nm 3950L 75 nm 93 nm 90 nm nm nm 220 nm nm 80 nm Fig 22: HPBW over tuning range, ical values and tolerance range. left: curves for LFP304L337; right: table for the currently existing filter es (measured with FTIR, ±6, 4 cm) 39 Advanced Features 4.2

140 Advanced Features The broad band pass and the pyroelectric detector element also show some spectral characteristics. The spectral response of the detector is a superposition of different fractions, but has to be considered as a whole in the application. At InfraTec, calibration measurements (figure 23) are performed by means of an FTIR spectrometer. The spectra are referenced to a black detector with a flat spectral response and normalized to the highest peak (relative spectral response) nm 66 nm V relatvie spectral response 4006 nm 65 nm 9.7 V 3206 nm 59 nm 29.5 V 3400 nm 59 nm V 498 nm 70 nm 4.40 V CWL = 438 nm HPBW = 80 nm Vc = V 3596 nm 3800 nm 63 nm 62 nm V V λ [µm] 4.6 Fig 23: Relative spectral response of a FPF detector LFP304L337 at several tuning voltages 4.3 Optical Considerations 3B The basic theory described in section 4. is restricted to simplified conditions, which requires a normal incident and perfectly collimated beam. An inclined but collimated beam results in a negative drift of the CWL (figure 24 left), but the most common case is an uncollimated beam with a certain angle of divergence and intensity profile. The resulting transmittance spectrum can be seen as the superposition of collimated raybeams with different angles of incidence and intensities. The superimposed spectrum has a broader HPBW and the CWL at slightly lower wavelengths (figure 24 right). Fig 24: Influence of angle shift and divergence angle on bandwidth and peak transmittance of a FPF 40

141 This effect is very well known from fixed interference filters but much more pronounced for FPF with a tunable air gap. Figures 25 and 26 show theoretical and measured values of the angle shift, relative to the ideal case (collimated). Fig 25: Relative shift of the CWL over the full cone angle, theoretical and measured with FTIR (mean angle of incidence 0 ) Fig 26: Relative shift of the HPBW over the full cone angle, measured with FTIR (mean angle of incidence 0 ) Wavelength shift depends only on the intensity distribution within the cone angle but not on the finesse. The thick curve (figure 25) may be considered as the worst case: a source with a lambertian intensity distribution. In practice higher angles often carry less intensity, which seems to be case in the FTIR measurement shown through the dashed curve. In contrast to the wavelength shift, the broadening effect depends on intensity distribution and the finesse (reflectance and surface defects of the mirrors). A higher finesse results in a stronger broadening (figure 26 upper limit) and vice versa. In the discussion above, normal incidence was considered. It is important to note, that illumination with an oblique (mean) and convergent (or divergent) ray bundle shift effects become even stronger and the spectra may be distorted dramatically. Angle shift results in very important conclusions for the design and operation of FPF based analyzers or microspectrometers: The spectral performance of an instrument strongly depends on the optical conditions. As a consequence, the calibration of an FPF based instrument (wavelength and resolution) should be carried out within the final optical setup. For each particular application a compromise between spectral resolution and signaltonoise ratio SNR (throughput) needs to be found. This is a principal rule, which is valid for all kinds of spectrometers. Beam divergence can be minimized by using a light source with collimated output or by means of an additional prefixed aperture (figure 27 left). If the goal is to maximize the optical throughput, then focusing optics can be used, but larger cone angles will be a side effect (figure 27 right). 4 Advanced Features Advanced Features

142 Advanced Features High Resolution High SNR Sample cell IRsource Aperture Sample cell IRsource collimated output FPDetector 7B Focusing optic FPDetector Fig 27: Possible optimizations for the optical design of a microspectrometer with FPF detector left: illumination with a parallel beam; right: illumination with a large cone angle Figure 28 shows the correlation of the achievable SNR with a given spectral resolution, measured with two tested measurement set ups according to figure 27. Please note that a parallel beam ø mm offers the highest spectral resolution but only 3 % of the intensity and thus the resulting low detector signal voltage compared to an illumination using f/.4 optics..000 High Resolution parallel beam Ømm.000 SNR High SNR f/.4 optics R = λ/ λ 80 Fig 28: Measurements of the SNR vs. spectral resolution (LFP304L337, modulated IR source at Hz); left end point: Illumination with a large cone angle using f/.4 optics right end point: Illumination with a parallel beam ø mm 42

143 Advanced Features 4.4 Filter operation The filter is electrostatically driven. The control electrode (Vc) is arranged at the fixed reflector carrier, while the movable reflector carrier acts as the counter electrode with the fixed reference potential Vcref (see figure 2). Applying a tuning voltage Vc = Vc Vcref results in an electrostatic force Fel decreasing the electrode gap del. Fel 0 AelVc2 (3) 2 d el2 As a first approximation the mechanical behavior of the FPI is that of an overdamped massspring system. Unfortunately, due to some nonlinearities like electrostatic softening and the squeeze film effect, damping ratio and effective stiffness of the system are functions of the actual mirror position and hence the filter wavelength. This behavior results to give a first overview in some practical constraints: The filter is sensitive to acceleration forces: to vibrations (dynamic case) and to the position with respect to the earth s gravity as well (quasi static case). Filter settling depends on wavelength. The filter shows a stability limit at the socalled pullin point. This should never be exceeded during operation, otherwise the filter could be damaged. The filter wavelength can shift with temperature due to thermal expansion of the spacer layer. Again it should be pointed out, that nearly all parameters, which describe the optical and mechanical behavior of the filter, depend on the mirror position and therefore on the filter wavelength. The points listed above are described in more detail in the following sections Electrostatic tuning 8B The quasistatic control characteristic is dominated by the quadratic dependence of the electrostatic force from the control voltage and the effective stiffness. Figure 29 shows a ical curve for the detector e LFP304L337. Other filter es may differ in the voltage range but will exhibit the same behavior qualitatively. Fig 29: Typical steadystate control characteristic for LFP304L Advanced Features 4B

144 Advanced Features By analyzing equation (3) a positive feedback of del to the electrostatic force Fel becomes evident (electrostatic softening). The maximum stable operation range of a voltage controlled electrostatic actuator is therefore limited by the so called pullin instability. The pullin voltage should never be exceeded; otherwise the device may suffer irreparable damage. In practice this means: For each individual device (FPF) exists a maximum allowable control voltage for save and stable operation. Because of the fabrication tolerances, no general document like datasheets or application notes can provide this information to the user. One can obtain this from the individual measurement report only. Furthermore, the polarity of the control voltage needs to be maintained, even as in equation (3) this does not seem to be necessary Dynamic behavior 9B The dynamic behavior of the filter can be approximated by a position dependent mechanical time constant τ (first order low pass), determined by stiffness and damping. For shorter wavelengths the system reacts slower, because the effective stiffness of the system is low and the air damping is high. Figure 30 gives ical values and the tolerance ranges, where τmin corresponds to the upper and τmax to the lower end of the tuning range. Filter code τmin τmax Tolerance range 304L 2 ms 55 ms (±5 20) ms 3950L ms 35 ms (±5 20) ms ms 2 ms (± 4) ms Fig 30: Time constant over wavelength, ical values and tolerance ranges; left: curves for LFP304L337; right: tabulated values for the currently existing filter es Settling B When the filter is tuned from one wavelength to another by a control voltage step, it should be allowed to settle before the measurement is continued. The required settling time depends on the (absolute or relative) wavelength accuracy needed for the application and the step size. It can be calculated through the values given in figure 30. To give an example: The wavelength should be switched from 3.7 µm to 3.6 µm (e 304L), the time constant in this region is about 20 ms. The settling time for the filter to stabilize within a tolerance of 5 nm of the final value (5 nm/ nm = 5 %) is 3 * τ = 60 ms. 44

145 Unfortunately, for the practical use of an FPF with a pyroelectric detector this is only part of the truth. Switching from one wavelength to another also causes a modulation of the radiation falling on the detector. In the worst case, a step over the entire tuning range, the detector sees the complete spectrum (similar to the sweep mode, see section 4.5). Decisive for the settling of the detector output is the longest time constant in the system, which is the thermal time constant of the pyroelectric detector (in the range of 50 ms). How fast the measured value settles, depends on the signal processing, too (bandwidth of software filtering, FFT/LockIn). This subject is quite complicated and out of the scope of this application note Acceleration response B If the filter is exposed to acceleration forces, the upper reflector carrier will move and cause the filter wavelength to shift. The quasistatic response, like turning the filter with respect to the earth s gravity, depends mainly on the effective stiffness and on the mass of the movable reflector. Figure 3 gives ical values and tolerance ranges, where CWLmin corresponds to the upper and CWLmax to the lower end of the tuning range. Filter code CWLmin CWLmax Tolerance range 304L 2.5 nm/g 36 nm/g (±2.5 6) nm/g 3950L 2.5 nm/g 32 nm/g (±2.5 5) nm/g nm/g 65 nm/g (±7 25) nm/g Fig 3: Wavelength shift CWL by gravity when turning the filter upsidedown (± g), ical values and tolerance ranges; left: curves for LFP304L337; right: tabulated values for the currently existing filter es ( g = 9.8 m/s²) In addition, the filter responds to dynamic vibrational forces, too. Due to the squeeze film effect, high frequency vibrations (see figure 30 for the mechanical time constants) are effectively damped Temperature shift 2B Interference filters are generally prone to a temperature shift, which is partly caused by purely mechanical expansion of the dielectric thin films and partly by a change of the optical constants of the materials. In case of tunable FP filters, the temperature shift is dominated by thermal expansion of the spacer layer, which defines the width of the air gap. As a temperature change mainly results in a mechanical detuning of the gap, the correlation between HPBW and CWL remains unchanged. Again this effect is wavelength depended. At a given wavelength the temperature shift is nearly linear, and therefore a temperature coefficient TCλ can be given. For shorter wavelengths the shift becomes larger, because of the reduced effective stiffness. Figure 32 gives ical values and tolerance ranges, where TCλ min corresponds to the upper and TCλ max to the lower end of the tuning range. 45 Advanced Features Advanced Features

146 Advanced Features Filter code TCλ min TCλ max Tolerance range 304L 2.0 nm/k 4.0 nm/k (± ) nm/k 3950L 2.0 nm/k 3.8 nm/k (± ) nm/k nm/k 3.2 nm/k (±0.5.0) nm/k Fig 32: Temperature coefficient of the CWL, ical values and tolerance ranges; left: curves for LFP304L337; right: tabulated values for the currently existing filter es Driving circuit 3B Figure 33 shows a suggestion of a driving circuit for variable color detectors. Gain and maximum control voltage should be selected according to the filter e. They can be adjusted through resistors R2 and R3. The pins Shield, Substrate and Vcref should be on the same stabilized, lowimpedance potential. Otherwise, spikes, ripples or other interfering signals at these circuit points or the control voltage as well may cause cross talk to the pyroelectric detector due to parasitic capacitances. The combination C5 and R2 form a low pass filter, which helps to reduce voltage transients and therefore to reduce false signals. The time constant of any electrical filtering should be as high as possible, but should not exceed the mechanical time constant, so that the mechanical filter performance (settling) is not affected. 5V C nf Order Sorting Filter V Out R Vc, max gain 2.5 V V R3 Vout R 470k 5V Filter code [ V] 304L 33.8 V kω 2 kω VC in [ V] 3950L 69.5 V kω 5.6 kω OPA227, OP77 VC2 GND Vc max gain R2 R3 nf 30R n 200p n pF Substrate C3 220nF Shield VC 30R VC ref OPA 445 C5 Case R2 R3 5V C4 220nF V kω 4.7 kω Fig 33: Left: Recommended driving circuit for variable color detectors; right: dimensioning of the filter driving amplifier for several voltage ranges All data given in this note show the current stage of FabryPérot product development. Our R&D team constantly works on further improvements which will be published in a suitable way such as updated data sheets. 46

147 Advanced Features Operation modes and measurement methods The capabilities of variable color detectors are numerous. Depending on the measurement task and operation mode, different advantages compared to conventional single or multi channel detectors with fixed NBP filters can be found. Hereafter three different operation modes will be explained in detail: Sequence of channels In the simplest case several fixed detector channels shall be substituted by a tunable detector. The filter is sequentially adjusted to the individual spectral channels. Besides the higher flexibility and expandability additional benefits may be given: Simple multi channel detectors have separated apertures, which yield to the well known issues regarding nonuniform illumination, longterm stability, source drifting, pollution, etc. Tunable filter devices do not have these problems due to their principal design and singular light path. Detectors with an internal beamsplitter also have a common aperture, but each channel is getting only a fraction of the whole radiant power. Applying the sequential measurement we can always use the whole incident radiant power. For four different channels and comparable conditions regarding aperture size and filter bandwidth theoretically a duplication of the SNR can be reached. Step scan The method described above can still be expanded in such a way that continuous spectra can be obtained. The required acquisition time for the mapping of a spectrum depends on the following facts: Number of measuring points (wavelength range, step size): To get a continuous spectrum it must be scanned at minimum with a step size which corresponds to the half of the filter bandwidth (sampling theorem). Moderate oversampling can be useful, but will increase the measurement time. Recordings of the measuring points (modulation frequency, integration time): These parameters define the SNR. Beside the detector properties and the applied analysis methods, the radiant power, modulation depth of the IR source and the design of the measuring section are crucial. Settling time of the filter: The actual settling time of the filter depends on the wavelength as described earlier. It should therefore be implemented variably to achieve an optimum of speed. As an example for measurements with the stepscan mode, figure 34 shows spectra of a polystyrene foil. The red squares are the steps of the FPF (LFP304L337), whereas the solid line is measured with an FTIR spectrometer for comparison. 47 Advanced Features 4.5

148 Advanced Features 80 Transmission charaterization of Polystyrene foil Transmittance [%] 60 LFP304L337 FTIR 8/cm λ [nm] 4000 Fig 34: Measurement example for the step scan mode (Polystyrene foil) LFP304L337: spectral resolution R = 65; SNR,000:; data points; acquisition time s Continuous scan (Sweep mode) By using a pyroelectric detector only modulated radiation can be analyzed. Normally this is realized by mechanical chopping or electrical modulation of the IR source. However, if the filter is continuously scanned (sweeped) the spectral information can be directly used for the modulation. The filter is actuated dynamically in this case. This particular operation mode has principally the potential to accelerate the recordings of spectra remarkably. One possible application is the fast (presence) detection of films (e.g. a lubricant on a metal surface). Two basic approaches are possible for a dynamic operation: Presetting of voltage characteristics Vc(t) for filter modulation (sinusoidal, ramp or similar ) and Detection of the resulting function CWL(t) by an adequate calibration scheme for example with wavelength standards (e. g. NBP filters) or Evaluation of the detector signal with dedicated software algorithms (chemometric techniques) Presetting of a designated function CWL(t) and determination of the appropriate voltage characteristic Vc(t) for example with wavelength standards 48

149 Advanced Features 3 5% λ [nm] FTIR 20 % 99% 97% 95% 80 93% 9% LFP304L337 89% FTIR 4/cm Transmittance [%] FTIR Normalized detector signal 3% 60 87% 40 85% scantime [ms] LFP304L Fig 35: Measurement example for the sweep mode with dynamic filter tuning (methane) Figure 35 gives an example for the dynamic operation. The IR source is working in DC operation, while the filter goes through the desired wavelength range. Except for the DCportion, the whole spectral information is contained in the generated detector signal. For the filter actuation and signal processing the dynamic properties of both, filter and detector, have to be considered. 4.6 Summary 6B With the extension of our product range by variable color detectors additional technologies are available for our customers. All es of our multispectral detectors are complementing one another: Conventional dual and quad channel detectors can be used in competitive volume applications Our dual and quad channel beamsplitter detectors with one aperture are used as long term stable and very accurate measuring modules for different spectral channels Variable color detectors with a high SNR allow a more flexible operation of the analyzer enabling for example the detection of adjoining or overlapping absorption bands. They are also of interest for applications, where more than 4 spectral channels shall be scanned within a short time frame. 49 Advanced Features Transmission characterization of 2.2 Vol% Methane

150 Notes 50

151 Temperature Behavior Te m p e ra tu re s h ift o f N B P filte r "C O 2 s ta n d a rd " [D ] C O 2 s ta n d a rd [D ] N B P µm / 8 0 nm T ra n s m itta n c e [% ] 80 5 C C W a ve le n g th [n m ] 4400 Temperature Behavior stateoftheart CMOS OpAmp circuitry usual JFET circuitry JFET = Junction Field Effect Transistor OpAmp = Operational Amplifier Compensation element Gate resistor Active element JFET Feedback resistor and capacitance Operational Amplifier IR Filter Introduction 52 Temperature dependent Components within the Pyroelectric Detector 52 The Effects of Temperature Variation on overall Performance 56 Variation of ambient Temperature and Temperature Compensation 62 Summary 66

152 Temperature Behavior Introduction This application note is offered to provide some insight into how temperature affects the various components of a ical pyroelectric detector and how the effects of ambient temperature variations on detector performance can be minimized. Pyroelectric detectors can be used over a wide ambient temperature range without cooling or stabilizing. The active elements react to changes of incoming radiation levels. This effect is used to create an electrical detector signal. Changes of ambient temperature will cause drift of the detector signal and noise expressed by the temperature coefficient (TC), because the components used within a detector change their properties with temperature. Also fluctuations or instability in detector output can be caused by temperature changes especially in temperature ramps. To minimize such instabilities thermal compensation of the sensitive pyroelectric element is a very effective means of prevention. Both effects should always be considered separately since they are caused by factors that require different corrective measures in detector design. 2 Temperature dependent Components within the Pyroelectric Detector Figure shows the basic commercial single element pyroelectric detector offered by InfraTec. In the figure there are the temperature dependent active and passive electrical and optical components indicated. stateoftheart CMOS OpAmp circuitry usual JFET circuitry JFET = Junction Field Effect Transistor OpAmp = Operational Amplifier Compensation element Gate resistor Active element JFET Feedback resistor and capacitance Operational Amplifier Fig : IR Filter Typical InfraTec detector construction The change of properties of the individual components results in a signal or noise density change of the complete detector represented by the Temperature Coefficient TC [ppm/k]. 52

153 Temperature Behavior 2. Temperature dependence of the pyroelectric chip In most practical applications, where operating ambient temperatures are substantially lower (<20 C), the intrinsic temperature coefficient (TC) of the pyroelectric current is approximately 3500 ppm/k (0.35 %/K). In a ical application, the active element of the pyroelectric detector is coated with an appropriate black coating to enhance the infrared absorption of chopped or modulated incoming radiation, thus warming the pyroelectric crystal. Depending on the operating mode of the detector, the resulting current or voltage generated above the capacitance of the detector chip (ically 50 pf) is then converted into a useful signal. The electrical charges (current) generated even by minimal increases in crystal temperature are in the order of femto to nanoamperes. It is important to note that an increase in detector case/package temperature can produce false signals. Electrostatic peaks of up to 50 V, for example, have been measured from highly insulated elements with case temperature increases as small as C. 2.2 Temperature dependence of integrated JFET and CMOS operation amplifier The gate leakage current, as well as the input current noise of integrated Junction Field Effect Transistors (JFETs), increase substantially with increases in temperature. Particularly at higher temperatures, this increase is exponential. The gate leakage current of a ical FET is normally less than pa at 25 C, but can increase to well above pa at 25 C. CMOS operational amplifiers (OpAmps) use an insulated input which enables an ultra low input bias current and low noise. The OpAmp circuitry is best suited at high temperatures up to 85 C (see figure 2). Another temperature effect can be created by the amplification drift of JFET or OpAmp. Increases in temperature will reduce the JFET commonsource forward transconductance and increase the pinchoff voltage. Due to the high openloop amplification and strong negative feedback of the OpAmps a drift of the OpAmp circuitry amplification determined by the temperature is not observed. 53 Temperature Behavior By definition, the Curie point is that temperature above which the lowtemperature pyroelectric polarized phase is transformed into a hightemperature nonpyroelectric unpolarized phase. The pyroelectric coefficient of these materials, which is a measure of eventual detector sensitivity, actually increases with increasing temperature up to the Curie point. In the case of Lithium Tantalate (LiTaO3), from which almost all of InfraTec s pyroelectric detectors are made, the Curie temperature is 603 C.

154 Temperature Behavior 0 Noise density [µv/hz½] Noise of LME35 (CMOS) and LME300 (JFETexternal OPA277) detector design (both with identical feedback resistor of 5 GOhm) JFET 85 C CMOS 25 C CMOS 85 C JFET 25 C 0 Fig 2: 2.3 Frequency [Hz] 0 Different behavior of JFET and CMOS input transimpedance amplifiers at temperature increase Temperature dependence of gate resistor as well as feedback components HighMegohm resistors used as gate resistors in JFET circuitry or feedback resistors in OpAmp circuitry are characterized by high negative temperature coefficients (i.e. resistance decreases with increasing temperature). GOhm resistors, that are routinely used with certain es of pyroelectric detectors, ically have TC s of about 2,000 ppm/k. In voltage mode operation the change of the gate resistor resistance does not influence the output signal above the electrical cutoff frequency of about 30 mhz. The detector noise will however increase proportionally by / R). In current mode operation the change of the feedback resistance value will influence both signal and noise. NPO capacitors as well as printed parallel strip lines are used as feedback capacitors in OpAmp detectors and hence there is no measurable temperature influence on the detector parameters. 2.4 Temperature dependence of IR filters and windows InfraTec pyroelectric detectors are coated with a black absorption coating whose spectral characteristics have been demonstrated not to be temperature dependent over the storage and operating temperature range. Please note that the maximum storage and operating temperature for detectors with metal black layer (applies only to LIE32 and LIE332 es) is only 60 C. Above this temperature the high absorption foamy structure of the metal black layer will irreversibly sinter, which will cause a reduced absorption capability The spectral transmittance of all windows and filters as part of the detector package varies with temperature. For uncoated IR optical materials (e.g. CaF2), temperature variation will mainly affect their transmittance and absorption edge (hence their useful range). The spectral thermal shift and changes in transmission characteristics of coated filters, however, is determined by the materials and coating design used to manufacture such filters, and therefore vary by the e of filter (e.g. narrow band pass NBP, wide band pass WBP), wavelength region and filter manufacturer. 54

155 Temperature Behavior Depending on customer requirements InfraTec uses IR filters manufactured with a low TC design (ical temperature shift approx nm/k, ical angle 5 approx. 27 nm, see figure 3) or a low angular shift design (ical temperature shift approx nm/k, ical angle 5 approx. 5 nm, see figure 4). All integrated narrow bandpass filters in InfraTec pyroelectric detectors for the 3 to 5 micron region have been chosen for their stability in design and are ically deposited on silicon substrates. Temperature shift of NBP filter "CO2 standard" [D] CO2 standard [D] NBP 4.26 µm / 80 nm 5 C C Wavelength [nm] Fig 3: Temperature shift of NBP filter with low TC design Temperature shift of NBP filter "CO2 high AOI" [Z] CO2 high AOI [Z] NBP 4.27 µm / 70 nm Transmittance [%] 80 5 C C Wavelength [nm] Fig 4: Temperature shift of NBP filter with low angular shift design As a general rule, as temperature increases, IR bandpass filters will shift to longer wavelengths with some loss in transmittance. In contrast, with increasing angle the CWL will shift to shorter wavelengths in general. 55 Temperature Behavior Transmittance [%] 80

156 Temperature Behavior 3 The Effects of Temperature Variation on overall Detector Performance 3. Change of Responsivity with temperature Standard applications never analyze the pyroelectric current from the active element itself but the signal voltage generated by the pyroelectric current (voltage responsivity). Therefore the resulting TC of the pyroelectric detector depends on the operating mode of the detector, either the element in the opencircuitoperation (voltage mode detectors, JFET circuitry) or in short circuit configuration (current mode detectors, OpAmp circuitry). Due to the electrothermal conversion the pyroelectric current is proportional to the quotient of the pyroelectric coefficient p and the volume specific heat capacitance cp. In current mode the voltage signal is generated by the pyroelectric current flowing through the feedback resistor. The TC of responsivity in current mode is therefore influenced by the TC of the pyroelectric coefficient, the TC of the volume specific heat and the feedback resistor. In voltage mode in most cases additionally the TC of the relative permittivity of the pyroelectric material has to be included. As examples hereafter some experimental data from a simple setup is included to demonstrate the importance of understanding how system parameters interact. The temperature behavior of responsivity is presented in the following figures (also applies to the signal voltage measured directly at the detector). InfraTec pyroelectric detector signals are nearly linear with temperature over the whole operation temperature range. Please note that the compensation element in a thermally compensated detector does not contribute to the output signal, therefore the TC of responsivity applies for both thermally compensated and uncompensated detectors. 5% Temperature coefficient (TC) of responsivity LME3026 (JFET), 500 K black body Responsivity Rv/Rv@25 C 4% 5 Hz 3% Hz 2% 20 Hz % TC = 200 ppm/k % 25 Fig 5: Temperature [ C] LME3026 (single channel; TO39 housing; medium chip size; low Micro; JFET; voltage mode; ch: CaF2 0.7 mm thick) 56

157 Temperature Behavior Detectors with JFET circuitry and without windows have ical TC s in the range of (, ) ppm/k, because the TC s of the single components are almost compensated. The temperature behavior of detectors with OpAmp circuitry depends significantly on the modulation frequency. Above the electrical cutoff frequency the resulting TC becomes more and more positive with a saturation at about 2,000 ppm/k. Below the electrical cutoff frequency the additional influence of the negative TC of the feedback resistor will decrease the TC of the responsivity. The detector LME3356 has an electrical time constant of about 20 ms ( GOhm // 0.2 pf). The electrical cutoff frequency is around 8 Hz. TC behavior changes around these limits as shown in figure 6. % Temperature Behavior Temperature coefficient (TC) of responsivity LME3356 (OpAmp), 500 K black body Responsivity Rv/Rv@25 C 8% 5 Hz 6% Hz 20 Hz 4% TC (20 Hz) = 300 ppm/k TC (5 Hz) = 0 ppm/k 2% % 25 Fig 6: Temperature [ C] LME3356 (single channel; TO39 housing; medium chip size; thermal compensation; low Micro; OpAmp; current mode; feedback GOhm; ch: CaF2 0.7 mm thick) Typical values for OpAmp detectors (with different filters or crystal windows and different feedback resistors) for different modulation frequencies are in the range of (500 2,000) ppm/k. Additionally, measurements with dual channel detectors and NBP filters were carried out. In a dual channel configuration with measurement and reference channel temperature influence can be reduced by using the quotient of both detector signals. 57

158 Temperature Behavior For a ical voltage mode detector LIM222GH with NBP filters the following results were received: 4% Temperature coefficient (TC) of responsivity LIM222GH (JFET), 500 K black body Responsivity RV/RV25 C 2% % TC R V: 300 ppm/k 98% 96% Resulting TC ratio Ch / f > Hz Average TC f > Hz TC R V: 850 ppm/k 94% 20 Fig 7: Temperature [ C] 80 Dual channel detector LIM222GH (TO39 housing; small chip size; thermal compensation; JFET; voltage mode; ch: NBP 3.40 µm/20 nm HC; ch2: NBP 3.95 µm/90 nm Ref.) It illustrates a configuration which generates a slightly negative resulting average TC of 300 ppm/k (channel =,000 ppm/k, channel 2 = 700 ppm/k). Applying the ratio between the signal of the gas channel (channel ) and the reference channel (channel 2) the impact of aging and pollution in the optical path can be compensated (red curve). According to the Theory of Errors the resulting TC emerges from the ratio for TCch TCch2 (in figure 7 (,000 ppm/k) (700 ppm/k) = 300 ppm/k). In principle, positive and negative values can emerge for the resulting TC through this ratio. The CMOS OpAmp equipped LIM262GH has been tested under the same arrangement and conditions as LIM222GH. The current mode detector s ically positive TC of responsivity was measured. The TC for this individual detector is in the range of ( ) ppm/k, depending on the modulation frequency. Again in this case, the resulting TC is calculated from the Channel /Channel 2 ratio as a difference of TCch TCch2. Depending on the TC value of the single channel, positive and negative values can emerge, based on the calculated difference. 58

159 Temperature Behavior 4% Temperature coefficient (TC) of responsivity LIM262GH (OpAmp), 500 K black body 2% TC R V: 50 ppm/k % TC RV: 50 ppm/k Average TC f > 30 Hz Average TC f < Hz Resulting TC ratio Ch / f > 30 Hz Resulting TC ratio Ch / f < Hz TC RV: 200 ppm/k 98% 20 Fig 8: Temperature [ C] 80 Dual channel detector LIM262GH (TO39 housing; small chip size; thermal compensation; OpAmp; current mode; feedback GOhm; ch: NBP 3.40 µm/20 nm HC; ch2: NBP 3.95 µm/90 nm Ref), identical filter placement as with the LIM222GH in figure 7. Change of detector offset voltage with temperature in stable stage Due to the increase in pinchoff voltage and gate leakage current, higher temperatures will always increase the offset voltage at the JFET circuitry because the negative TC of the gate resistor does not compensate this increase. Figure 9 shows the offset voltage vs. temperature of ical InfraTec detectors with JFET circuitry. Offset voltage [mv] 200 Offset voltage vs. Temperature LME LME Fig 9: Temperature [ C] Offset voltage vs. temperature (JFET circuitry); after thermal transient period 59 Temperature Behavior Responsivity RV/RV25 C TC R V: 600 ppm/k

160 Temperature Behavior The DC offset voltage of the OpAmp circuitry is determined by the offset voltage of the OpAmp itself (ical in the range of max. ±5 mv) together with input bias current and feedback resistor. The bias current is about several pa at 85 C. Figure shows the offset voltage vs. temperature of ical InfraTec detectors with OpAmp circuitry. 0 Offset voltage vs. Temperature Offset voltage [mv] 800 LME335 ( GOhm) 600 LME35 (5 GOhm) Temperature [ C] Fig : Offset voltage vs. temperature (OpAmp circuitry); after thermal transient period Because the DC offset voltage is proportional to the product of input bias current and feedback resistance the increase at high temperatures is especially noticeable for detectors with large feedback resistors. 3.3 Change of Detector noise with temperature An increase in gate leakage (JFET) or input bias (OpAmp) current together with the neg. TC of gate (JFET) or feedback (OpAmp) resistance value results in higher detector noise with increasing temperature. This increase is particularly prominent at lower frequencies and for large resistance values (see figure and 2). 60

161 Temperature Behavior 250% Noise density vs. Temperature 50% % LME304 (5 GOhm) 50% LME36 (33 GOhm) LME302 (82 GOhm) 0% Temperature [ C] Fig : Noise density vs. temperature (voltage mode detectors with JFET) 250% Noise density vs. Temperature Urn/Urn@25 C 200% 50% % LME35 (5 GOhm) 50% LME335 ( GOhm) LME345 (24 GOhm) 0% Temperature [ C] Fig 2: Noise density vs. temperature (current mode detectors with OpAmp) Please note that all figures with measurement data show ical values, individual detectors may differ. The drift of detector signal, offset voltage and noise which were shown above are independent from integrated temperature compensation elements. Those elements do not contribute to the actual detector signal, but only help to compensate for effects of thermal fluctuation for example in temperature ramps and hence increase stability. 6 Temperature Behavior Urn/Urn@25 C 200%

162 Temperature Behavior 4 4. Variation of ambient temperature and temperature compensation Offset voltage in temperature ramps A change of the detector case temperature will usually generate a very low frequency signal, which can be of substantial magnitude. The commonly used voltage mode detectors with JFET circuitry are particularly susceptible to these temperature changes. Signals generated can cause unfavorable effects to a chosen preamplifier by pushing the limits of its operational range. The longer the thermal and electrical time constants of these detectors, the more sensitive they are to these changes. The stateoftheart CMOS OpAmp detectors present in temperature ramps a DC offset adjustment in the same dimension as voltage mode detectors but the normal measurement AC signal is about times higher. That means that the ratio DC offset adjustment to signal will be less than % of the JFET circuitry and hence the dynamic range will not be limited anymore. Since thermal and electrical time constants are determined by detector construction, they can be reduced by design to attenuate, but not completely eliminate, the effects of case temperature changes in uncompensated detectors. Offset voltage of an uncompensated voltage mode detector at various gate resistors during a temperature ramp.5 Offset voltage [mv] GOhm gate resistor temperature ramp GOhm gate resistor Temperature ramp [K/min] Case50 temperature 55 [ C] 60 Fig 3: Offset voltage vs. temperature at various gate resistors (uncompensated voltage mode detector, JFET circuitry) Figure 3 shows the ical effect of temperature variation on detector offset voltage for uncompensated voltage mode detectors with different gate resistors. A decrease of the gate resistor substantially increases the detector stability. But on the other hand noise is inversely proportional to the square root of the gate resistance, e.g. a 9times higher stability will cause a decrease of detector detectivity down to 33 %. To overcome the problems associated with detector instability due to case temperature changes, an additional optically inactive (shielded) detector chip, known as the compensation element, can be added inside the detector package. The detector is then called a compensated detector. The compensation element has the opposite polarity of that of the active element. As case temperature varies, charges generated at the 62

163 Temperature Behavior active and compensation element will essentially have the effect of canceling each other. Figure 4 shows the offset voltage vs. temperature of thermally compensated detectors, clearly presents the effectiveness of this arrangement. Offset voltage [mv] temperature ramp uncompensated 0 compensated Case temperature [ C] 60 Fig 4: Offset voltage vs. temperature (compensated and uncompensated voltage mode detectors, JFET circuitry) Thermally compensated pyroelectric detectors can be classified into two es: a) serial or b) parallel compensated, depending on the electrical connection of the active and the compensation element (see figure 5). The compensation element is always completely optically shielded from incoming IR radiation, hence although optically inactive but still an electrically effective capacitor. The influence of the compensation element regarding signal and detectivity is different between the common JFET circuitry and the stateoftheart CMOS OpAmp circuitry. The net effect of compensation for usual JFET circuitry is a reduction of detectivity to approximately 60 % for both compensation es, although signal and noise will be affected differently for each e. The approximate values of signal and noise for each e of compensated detector are shown as a percentage of those of an uncompensated detector in the figure above. Due to the virtual short of compensation and pyroelectric element in the stateoftheart OpAmp circuitry the parallel compensation neither causes signal nor detectivity losses. 63 Temperature Behavior 5 Offset voltage of a compensated and an uncompensated voltage mode detector during a temperature ramp Temperature ramp [K/min] 5000

164 Temperature Behavior Serial Compensation (Only with InfraTec s LIM34) Serial Compensation JFET circuitry: % signal; 70 % noise OpAmp circuitry: not reasonable Parallel Compensation JFET circuitry: 50 % signal; 70 % noise OpAmp circuitry: % signal; % noise Parallel Compensation Fig 5: Serial and parallel compensation to increase the stability of the DC operating point of pyroelectric detectors in temperature ramps The decision to use serial or parallel compensation for JFET voltage mode detectors should be based on the operating conditions from the detector. Parallelcompensated detectors are more stable at strong (more than 2 K/min) or long time constant temperature ramps (longer than hour). Therefore most of InfraTec detectors are using parallel compensation. On the other hand the user may prefer the double signal of the serialcompensated voltage mode detector. We always recommend to test parallel compensation first. In current mode detectors with integrated OpAmps the signal of compensated detector es is not changed due to the short circuit operation. Due to that fact it is no longer necessary to compromise between signal magnitude and stability, only parallel compensation is applied for those current mode detectors. 4.2 Offset step response after fast temperature change Often it is of interest to know how fast a detector can recover from an external temperature jump of the complete system. In the following figures a ical reaction of the signal output by a fast increase of the ambient temperature from (25 40) C which is transmitted to the detector housing is shown. The start of the jump reaction depends on the time which is needed to transfer the ambient temperature into the detector body. In figure 6 ical curves for voltage mode detectors are shown. The offset jump of the uncompensated detector is very large and limited by the supply voltage. In comparison, the step response of the compensated detector is very small and the detector recovers much faster from the temperature jump. Please note that fabrication tolerances prevent an exact compensation and the step response could be either positive or negative. It is impressive to see the effect of thermal compensation realized by use of a second pyroelectric chip which is antiparallelconnected to the active chip in the detector. 64

165 Temperature Behavior Offset step response of voltage mode detectors 8 LIM22 (uncompensated) 6 Uo[V] LIM222 (compensated) t [s] 40 Fig 6: Change of offset voltage vs. time of ical voltage mode detectors after fast temperature increase Similar reactions can also be noted for detectors in current mode. Figure 7 shows a ical step response of current mode detectors with integrated operational amplifier. Offset step response of current mode detectors U0[V] 0 LMM44 (5 GOhm, uncompensated) LMM244 ( GOhm, compensated) LMM244 (5 GOhm, compensated) t [s] Fig 7: Change of offset voltage vs time of ical current mode detectors after fast temperature increase It is also shown that for compensated detectors the step reaction can still further be minimized by use of a small feedback resistor with the disadvantage of a reduced detectivity. Due to the much lower electrical time constant the recovery time of a detector in current mode with integrated OpAmp even with an uncompensated detector is much shorter compared to a compensated detector in voltage mode. 65 Temperature Behavior 2

166 Temperature Behavior 5 Summary With this application note, InfraTec has attempted to provide IR system designers with some useful data regarding the effect of ambient temperature variation on pyroelectric detector performance due to the complex interaction of components as part of the detector assembly. As pyroelectric detectors are designed and incorporated into a specific application, designers must also consider how other system components (external to the detector) such as sources, optics etc. can alter the expected detector performance, too. The signal conditioning method of the software used also will influence the result. 66

167 JFET and OpAmp E q u iv a le nt In p u t N o is e Vo lta g e v s. F re q u e n c y Transfer Characteristics 500 VGS(off) = 0.7 V VDS = V 400 ID Drain Current ( µa) 6 ID = ma 2 8 ID = I DSS 4 TA = 55 C C C 0 0 k k k 0 0. f Frequency (Hz) HIGHLEVEL OUTPUT VOLTAGE vs HIGHLEVEL OUTPUT CURRENT 80 TA = 55 C AVD AVD LargeSignal Differential Voltage Amplification db V VOH OH HighLevel Output Voltage V VDD = 5 V TA = 40 C 3 TA = 25 C 2 TA = 25 C LARGESIGNAL DIFFERENTIAL VOLTAGE AMPLIFICATION AND PHASE MARGIN vs FREQUENCY VGS GateSource Voltage (V) IOH HighLevel Output Current µa VDD = 5 V RL = 50 kω CL= pf TA = 25 C Phase Margin Gain JFET and OpAmp en Noise Voltage nv / Hz VDS = V φom m Phase Margin f Frequency Hz Standard JFET For single and multi color detectors 68 Special JFET Design for single and multi color detectors (on request) 70 OpAmp2 CMOS very low power OpAmp for single and multi color detectors 72 OpAmp3 CMOS very low power OpAmp for use in single supply detectors and 74 low current detectors

168 JFET and OpAmp Pyroelectric detectors of InfraTec use for the first signal processing stage Junction Field Effect Transistors (JFET) and CMOS Operational Amplifiers (OpAmp) builtin in the detector housing. Specifications are adapted for highimpedance pyroelectric elements. Standard JFET For single and multi color detectors Features Very low voltage and current noise High input impedance Full performance from lowvoltage power supply, down to 2.5 V Low Gate leakage current for improved system accuracy Absolute maximum ratings GateSource / GateDrain voltage: 50 V Power dissipation: 50 mw Specifications (TA = 25 C unless otherwise noted) Parameter Symbol Test Condition Min IG = µa, VDS = 0 V ID = 0. µa, VDS = 5 V VDS = 5 V, VGS = 0 V VDS = 0 V, VGS = 30 V, TA = 25 C VDS = 0 V, VGS = 30 V, TA = 50 C ID = 0. ma, VDG = 5 V VDS = 5 V, VGS = 5 V IG = ma, VDS = 0 V Dynamic Typ Max Unit Static GateSource Breakdown Voltage V(BR)GSS GateSource Cutoff Voltage VGS(off) Saturation Drain Current IDSS Gate Reverse Current Gate Operating Current Drain Cutoff Current GateSource Forward Voltage CommonSource Forward Transconductance CommonSource Output Transconductance DrainSource OnResistance CommonSource Input Capacitance CommonSource Reverse Transfer Capacitance Equivalent Input Noise Voltage IGSS IG ID(off) VGS(F) gfs 60 V ma pa na pa V ms 5 µs,700 VDS = 5 V, VGS = 0 V, f = khz gos rds(on) VDS = 0 V, VGS = 0 V, f = khz Ciss VDS = 5 V, VGS = 0 V, f = MHz Crss en VDS = V, VGS = 0 V, f = khz 68 pf 6 nv/ Hz

169 JFET and OpAmp Standard JFET Specifications (TA = 25 C unless otherwise noted) Drain Current and Transconductance vs. GateSource Cutoff Voltage gfs IDSS ID = ma pa C 500 ma pa ID = ma TA = 25 C pa C 0. pa ma TA = 25 C na IG Gate Leakage (A) gfs Forward Transconductance (ms) DS = V, V GS = 0 V DS = V, V GS = 0 V f = khz 8 IDSS Saturation Drain Current (ma) Gate Leakage Current na VGS(off) GateSource Cutoff Voltage (V) VDG DrainGate Voltage (V) 200 Vishay Siliconix CommonSource Forward Transconductance vs. Drain Current Transfer Characteristics VGS(off) = 0.7 V VDS = V f = khz 25 C C 0.4 TA = 55 C C C E q u iv a le nt In p u t N o is e Vo lta g e v s. F re q u e n c y Circuit Voltage Gain vs. Drain Current 200 VDS = V AV 60 AV Voltage Gain 6 ID = ma VGS GateSource Voltage (V) ID Drain Current (ma) en Noise Voltage nv / Hz JFET and OpAmp TA = 55 C.2 20 VDS = V ID Drain Current ( µa) gfs Forward Transconductance (ms) VGS(off) =.5 V 8 ID = I DSS g fs R L Assume V RL 20 R Lg os DD = 5 V, V DS = 5V V ID 80 VGS(off ) = 0.7 V.5 V k k 0.0 k 0. ID Drain Current (ma) f Frequency (Hz) 69

170 JFET and OpAmp 2 Special JFET Design for single and multi color detectors (on request) Benefits Reliable operation at high temperature or increased ionizing radiation Disadvantage related to standard JFET Lower gain; higher output impedance Features Ultra high input impedance Low Gate leakage current for improved system accuracy Absolute maximum ratings GateSource / GateDrain voltage: 50 V Power dissipation: 50 mw Specifications (TA = 25 C unless otherwise noted) Parameter Symbol Test Condition Min Typ IG = µa, VDS = 0 V ID = 0. µa, VDS = 5 V VDS = 5 V, VGS = 0 V VDS = 0 V, VGS = 20 V, TA = 25 C IGSS VDS = 0 V, VGS = 20 V, TA = 50 C IG ID = 0. ma, VDG = 5 V ID(off) VDS = 5 V, VGS = 5 V VGS(F) IG = ma, VDS = 0 V Dynamic Max Unit Static GateSource Breakdown Voltage V(BR)GSS GateSource Cutoff Voltage VGS(off) Saturation Drain Current IDSS Gate Reverse Current Gate Operating Current Drain Cutoff Current GateSource Forward Voltage CommonSource Forward Transconductance CommonSource Output Transconductance DrainSource OnResistance CommonSource Input Capacitance CommonSource Reverse Transfer Capacitance Equivalent Input Noise Voltage 70 gfs V µa pa na µs 3 µs 8 k pa V VDS = 5 V, VGS = 0 V, f = khz gos rds(on) VDS = 0 V, VGS = 0 V, f = khz Ciss VDS = 5 V, VGS = 0 V, f = MHz Crss en VDS = V, VGS = 0 V, f = khz 70 pf 5 nv/ Hz

171 JFET and OpAmp Special JFET Specifications (TA = 25 C unless otherwise noted) JFET and OpAmp 200 Vishay Siliconix 7

172 JFET and OpAmp 3 OpAmp2 CMOS very low power OpAmp for single and multi color detectors LME335, /337, /34, /345, /35, /353, /392, /553, /54, /55; LIM052, /054, /62, /262; LMM242, /244; LFP304L337; LFP ; LFP Features Single [( ) V] and split supply [(± ±8) V] operation Low supply current; very low input bias current RailtoRail output swing; high voltage gain Absolute maximum ratings Supply voltage (V V): 6V Differential input voltage: ± supply voltage Voltage at output pin: (V) 0.3 V... (V) 0.3 V Current at input pin: ±5 ma Current at output pin: ±30 ma Current at power supply pin: ±40 ma Power dissipation: mw Specifications (TA = 25 C; V = 5 V; V = 5 V; RL > MΩ unless otherwise noted) Parameter Symbol Input Offset Voltage Input Bias Current Input Offset Current Common Mode Rejection Ratio Input CommonMode Voltage Range Large Signal Voltage Gain positive peak Output Swing negative peak Supply Current Slew Rate GainBandwidth Product Phase Margin Equivalent Input Noise Voltage Equivalent Input Noise Current VOS IB IOS CMRR Test Condition Static 5.0 V VIC 2.7 V VICR RL = M RL = k RL = M to Gnd RL = k to Gnd VO RL = M to Gnd RL = k to Gnd IS VO = 0V, No Load Dynamic V = ±.9V, RL = k, SR O CL =pf GBW m Vn f = khz In f = khz AV 72 Min 75 5 to , Typ Max Unit to 4, µv pa pa db V V/mV V/mV V 25 µa 20 V/ms khz Deg nv/ Hz fa/ Hz

173 JFET and OpAmp EQUIVALENT INPUT NOISE VOLTAGE vs FREQUENCY SUPPLY CURRENT vs SUPPLY VOLTAGE INPUT BIAS AND INPUT OFFSET CURRENTS vs FREEAIR TEMPERATURE V n Equivalent Input Noise Voltage nv//hz VN nv/ Hz 240 VO = 0 No Load VDD± = ± 2.5 V VIC = 0 VO = 0 RS = 50 Ω 200 IDD µa I DD Supply Current ua IIO Input Bias and Input Offset Currents pa IIIB IB and IIO OpAmp2 Specifications 25 IIB 20 5 IIO TA = 55 C 60 TA = 25 C 20 TA = 25 C TA = 40 C TA FreeAir Temperature C VDD ± Supply Voltage V 7 VDD± = ± 5 V RS = 20 Ω TA = 25 C f Frequency Hz Texas Instruments Incorporated VIC = 2.5 V TA = 40 C 3 TA = 25 C 2 TA = 25 C IOL LowLevel Output Current ma IOH HighLevel Output Current µa LARGESIGNAL DIFFERENTIAL VOLTAGE AMPLIFICATION AND PHASE MARGIN vs FREQUENCY 3 GAIN MARGIN vs LOAD CAPACITANCE Rnull = 200 Ω TA = 25 C Rnull = 500 Ω Rnull = 500 Ω 60 Gain 0 φ m Phase Margin om 45 φ om m Phase Margin AVD AVD LargeSignal Differential Voltage Amplification db Rnull = Ω Rnull = 50 Ω 30 Rnull = Ω f Frequency Hz k Ω VI 0 VDD Rnull = 200 Ω Rnull = Ω Rnull = 50 Ω Rnull = Ω 50 k Ω 4 2 RL Load Resistance kω 5 90 Phase Margin PHASE MARGIN vs LOAD CAPACITANCE 80 VDD = 5 V RL = 50 kω CL= pf TA = 25 C VDD = 5 V Gain Margin db 0 VDD = ± 5 V Rnull = 0 Rnull CL Rnull = 0 TA = 25 C VDD CL Load Capacitance pf CL Load Capacitance pf 5 JFET and OpAmp VIC =.25 V VIC = 0 TA = 55 C Differential Gain V/ mv 60 VO (PP) = 2 V TA = 25 C VDD = 5 V VDD = 5 V TA = 25 C V VOH OH HighLevel Output Voltage V VOL VOL LowLevel Output Voltage V DIFFERENTIAL GAIN vs LOAD RESISTANCE HIGHLEVEL OUTPUT VOLTAGE vs HIGHLEVEL OUTPUT CURRENT LOWLEVEL OUTPUT VOLTAGE vs LOWLEVEL OUTPUT CURRENT

174 JFET and OpAmp 4 OpAmp3 CMOS very low power OpAmp for use in single supply detectors and low current detectors LME336, /346, /352, LIE235, /24, /245, /25 Features Single supply [( ) V] operation and split supply [(±.35 ±5) V] operation Ultra Low supply current; low input bias current RailtoRail output swing; high voltage gain Absolute maximum ratings SingleSupply voltage (V V/GND): V Differential input voltage: ± supply voltage Voltage at output pin: (V) 0.3 V... (V) 0.3 V Current at output pin: ±50 ma Current at power supply pin: ±50 ma Power dissipation: mw (RL kohm) Specifications (TA = 25 C; V = 3 V; V = 0 V; RL > kω unless otherwise noted) Parameter Symbol Input Offset Voltage Input Bias Current Input Offset Current Common Mode Rejection Ratio Input CommonMode Voltage Range Large Signal Voltage Gain positive peak Output Swing negative peak Supply Current Slew Rate GainBandwidth Product Phase Margin Equivalent Input Noise Voltage Equivalent Input Noise Current VOS IB IOS CMRR Test Condition Static 0.0 V VIC.7 V VICR RL = M RL = k RL = M to Gnd RL = k to Gnd VO RL = M to V RL = k to V IS VO =.5 V, No load Dynamic =. to.9v V SR O AV (RL = k, CL =pf to.5v) GBW m Vn In f = khz f = khz 74 Min 65 0 to 2 3 Typ Max Unit to 2, , mv pa pa db V V/mV V/mV V 25 µa 25 V/ms khz Deg nv/ Hz fa/ Hz

175 JFET and OpAmp INPUT BIAS AND INPUT OFFSET CURRENTS vs FREEAIR TEMPERATURE HIGHLEVEL OUTPUT VOLTAGE vs HIGHLEVEL OUTPUT CURRENT IIB 20 IIO VDD = 3 V VIC =.5 V VDD = 3 V VOL LowLevel Output Voltage V 80 LOWLEVEL OUTPUT VOLTAGE vs LOWLEVEL OUTPUT CURRENT 3 VDD± = ± 2.5 V VIC = 0 VO = 0 RS = 50 Ω 90 VOH HighLevel Output Voltage V IIIB IB and IIIO IO Input Bias and Input Offset Currents pa OpAmp3 Specifications 2.5 TA = 40 C 2 TA = 25 C.5 TA = 85 C TA = 25 C 0.5 TA = 25 C TA = 85 C 0.8 TA = 25 C TA = 40 C TA FreeAir Temperature C IOH HighLevel Output Current µ A IOL LowLevel Output Current ma Texas Instruments Incorporated VDD = 3 V 2 RI = kω TA = 25 C VID = mv f Frequency Hz VDD Supply Voltage V 7 2 I DD Supply Current µ A TA FreeAir Temperature C TA = 25 C TA = 40 C TA = 25 C 5 TA = 85 C 5 50 UNITYGAIN BANDWIDTH vs LOAD CAPACITANCE VO = VDD/2 VIC = VDD/2 No Load RL = kω VDD = 3 V VIC =.5 V VO = 0.5 V to 2.5 V VDD = 3 V RS = 20 Ω TA = 25 C 70 RL = MΩ SUPPLY CURRENT vs SUPPLY VOLTAGE 80 0 VID = mv 2 B UnityGain Bandwidth khz VO = VDD/2 VIC = VDD/2 TA = 25 C f Frequency Hz VDD Supply Voltage V CL Load Capacitance pf 6 JFET and OpAmp VDD = 5 V AVD LargeSignal Differential Voltage Amplification V/mV 5 EQUIVALENT INPUT NOISE VOLTAGE vs FREQUENCY V n Equivalent Input Noise Voltage nv/ Hz LARGESIGNAL DIFFERENTIAL VOLTAGE AMPLIFICATION vs FREEAIR TEMPERATURE SHORTCIRCUIT OUTPUT CURRENT vs SUPPLY VOLTAGE I OS ShortCircuit Output Current ma VO(PP) Maximum PeaktoPeak Output Voltage V MAXIMUM PEAKTOPEAK OUTPUT VOLTAGE vs FREQUENCY

176 Notes 76

177 Handling Precautions OK >4.0 mm NO Heat sink clip recommended OK < NO fasten Thermal damage by soldering pull >2N turn press >N Handling Precautions bend use tongs >2.0 mm Electrostatic Discharge (ESD) Sensitivity and Protection 78 Soldering 79 Mechanical Stress 79 Cleaning 80 Simple functional Test 80