opt301集成的光电二极管和放大器

©1994 Burr-Brown Corporation PDS-1228B Printed in U.S.A. January, 1994 FPO 70% FEATURES l PHOTODIODE SIZE: 0.090 x 0.090 inch (2.29 x 2.29mm) l 1MΩ FEEDBACK RESISTOR l HIGH RESPONSIVITY: 0.47A/W (650nm) l IMPROVED UV RESPONSE l LOW DARK ERRORS: 2mV l BANDWIDTH: 4kHz l WIDE SUPPLY RANGE: ±2.25 to ±18V l LOW QUIESCENT CURRENT: 400µA l HERMETIC TO-99 APPLICATIONS l MEDICAL INSTRUMENTATION l LABORATORY INSTRUMENTATION l POSITION AND PROXIMITY SENSORS l PHOTOGRAPHIC ANALYZERS l SMOKE DETECTORS DESCRIPTION The OPT301 is an opto-electronic integrated circuit containing a photodiode and transimpedance amplifier on a single dielectrically isolated chip. The transimpedance amplifier consists of a precision FET- input op amp and an on-chip metal film resistor. The 0.09 x 0.09 inch photodiode is operated at zero bias for excellent linearity and low dark current. The integrated combination of photodiode and transimpedance amplifier on a single chip eliminates the problems commonly encountered in discrete de- signs such as leakage current errors, noise pick-up and gain peaking due to stray capacitance. The OPT301 operates over a wide supply range (±2.25 to ±18V) and supply current is only 400µA. It is packaged in a hermetic TO-99 metal package with a glass window, and is specified for the –40°C to 85°C temperature range. INTEGRATED PHOTODIODE AND AMPLIFIER 1MΩ OPT301 40pF 75Ω 2 8 3 5 4 1 VO V– λ V+ ® OPT301 SPECTRAL RESPONSIVITY Vo lta ge O ut pu t (V /µW ) Wavelength (nm) 100 200 300 400 500 600 700 800 900 1000 1100 0.5 0.4 0.3 0.2 0.1 0 0.5 0.4 0.3 0.2 0.1 0 Ph ot od io de R es po ns ivi ty (A /W )InfraredBlu e G re en Ye llo w R edUltraviolet Using Internal 1MΩ Resistor International Airport Industrial Park • Mailing Address: PO Box 11400, Tucson, AZ 85734 • Street Address: 6730 S. Tucson Blvd., Tucson, AZ 85706 • Tel: (520) 746-1111 • Twx: 910-952-1111 Internet: http://www.burr-brown.com/ • FAXLine: (800) 548-6133 (US/Canada Only) • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132 SBBS001 2 ® OPT301 OPT301M PARAMETER CONDITIONS MIN TYP MAX UNITS RESPONSIVITY Photodiode Current 650nm 0.47 A/W Voltage Output 650nm 0.47 V/µW vs Temperature 200 ppm/°C Unit-to-Unit Variation 650nm ±5 % Nonlinearity(1) FS Output = 10V 0.01 % of FS Photodiode Area (0.090 x 0.090in) 0.008 in2 (2.29 x 2.29mm) 5.2 mm2 DARK ERRORS, RTO(2) Offset Voltage, Output ±0.5 ±2 mV vs Temperature ±10 µV/°C vs Power Supply VS = ±2.25V to ±18V 10 100 µV/V Voltage Noise Measured BW = 0.1 to 100kHz 160 µVrms RESISTOR—1MΩ Internal Resistance 1 MΩ Tolerance ±0.5 ±2 % vs Temperature 50 ppm/°C FREQUENCY RESPONSE Bandwidth, Large or Small-Signal, –3dB 4 kHz Rise Time, 10% to 90% 90 µs Settling Time, 1% FS to Dark 240 µs 0.1% FS to Dark 350 µs 0.01% FS to Dark 900 µs Overload Recovery Time 100% overdrive, VS = ±15V 240 µs 100% overdrive, VS = ±5V 500 µs 100% overdrive, VS = ±2.25V 1000 µs OUTPUT Voltage Output RL = 10kΩ (V+) – 1.25 (V+) – 0.65 V RL = 5kΩ (V+) – 2 (V+) – 1 V Capacitive Load, Stable Operation 10 nF Short-Circuit Current ±18 mA POWER SUPPLY Specified Operating Voltage ±15 V Operating Voltage Range ±2.25 ±18 V Quiescent Current IO = 0 ±0.4 ±0.5 mA TEMPERATURE RANGE Specification –40 +85 °C Operating/Storage –55 +125 °C Thermal Resistance, θJA 200 °C/W NOTES: (1) Deviation in percent of full scale from best-fit straight line. (2) Referred to Output. Includes all error sources. SPECIFICATIONS ELECTRICAL At TA = +25°C, VS = ±15V, λ = 650nm, internal 1MΩ feedback resistor, unless otherwise noted. PHOTODIODE SPECIFICATIONS At TA = +25°C, unless otherwise noted. Photodiode of OPT301 PARAMETER CONDITIONS MIN TYP MAX UNITS Photodiode Area (0.090 x 0.090in) 0.008 in2 (2.29 x 2.29mm) 5.1 mm2 Current Responsivity 650nm 0.47 A/W Dark Current VD = 0V(1) 500 fA vs Temperature doubles every 10°C Capacitance VD = 0V(1) 4000 pF NOTE: (1) Voltage Across Photodiode. 6 3 ® OPT301 SPECIFICATIONS (CONT) ELECTRICAL Op Amp Section of OPT301(1) At TA = +25°C, VS = ±15V, unless otherwise noted. The information provided herein is believed to be reliable; however, BURR-BROWN assumes no responsibility for inaccuracies or omissions. BURR-BROWN assumes no responsibility for the use of this information, and all use of such information shall be entirely at the user’s own risk. Prices and specifications are subject to change without notice. No patent rights or licenses to any of the circuits described herein are implied or granted to any third party. BURR-BROWN does not authorize or warrant any BURR-BROWN product for use in life support devices and/or systems. OPT301 Op Amp PARAMETER CONDITIONS MIN TYP MAX UNITS INPUT Offset Voltage ±0.5 mV vs Temperature ±5 µV/°C vs Power Supply VS = ±2.25V to ±18V 10 µV/V Input Bias Current 1 pA vs Temperature doubles every 10°C NOISE Input Voltage Noise Voltage Noise Density, f=10Hz 30 nV/√Hz f=100Hz 25 nV/√Hz f=1kHz 15 nV/√Hz Current Noise Density, f=1kHz 0.8 fA/√Hz INPUT VOLTAGE RANGE Common-Mode Input Range ±14.4 V Common-Mode Rejection 106 dB INPUT IMPEDANCE Differential 1012||3 Ω||pF Common-Mode 1012||3 Ω||pF OPEN-LOOP GAIN Open-Loop Voltage Gain 120 dB FREQUENCY RESPONSE Gain-Bandwidth Product 380 kHz Slew Rate 0.5 V/µs Settling Time 0.1% 4 µs 0.01% 5 µs OUTPUT Voltage Output RL = 10kΩ (V+) – 1.25 (V+) – 0.65 V RL = 5kΩ (V+) – 2 (V+) – 1 V Short-Circuit Current ±18 mA POWER SUPPLY Specified Operating Voltage ±15 V Operating Voltage Range ±2.25 ±18 V Quiescent Current IO = 0 ±0.4 ±0.5 mA NOTE: (1) Op amp specifications provided for information and comparison only. 4 ® OPT301 ELECTROSTATIC DISCHARGE SENSITIVITY This integrated circuit can be damaged by ESD. Burr-Brown recommends that all integrated circuits be handled with ap- propriate precautions. Failure to observe proper handling and installation procedures can cause damage. ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications. NC NC–In 1MΩ Feedback Common OutputV– V+ NOTE: Metal package is internally connected to common (Pin 8). 8 4 2 6 1 3 5 7 Photodiode Area PIN CONFIGURATION Top View PACKAGE INFORMATION PACKAGE DRAWING PRODUCT PACKAGE NUMBER(1) OPT301M 8-Pin TO-99 001-1 NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book. Supply Voltage ................................................................................... ±18V Input Voltage Range (Common Pin) .................................................... ±VS Output Short-Circuit (to ground) ............................................... Continuous Operating Temperature ................................................... –55°C to +125°C Storage Temperature ...................................................... –55°C to +125°C Junction Temperature .................................................................... +125°C Lead Temperature (soldering, 10s) ................................................ +300°C ABSOLUTE MAXIMUM RATINGS 6 5 ® OPT301 TYPICAL PERFORMANCE CURVES At TA = +25°C, VS = ±15V, λ = 650nm, unless otherwise noted. NORMALIZED SPECTRAL RESPONSIVITY N or m al iz ed C ur re nt o r V ol ta ge O ut pu t Wavelength (nm) 100 200 300 400 500 600 700 800 900 1000 1100 1.0 0.8 0.6 0.4 0.2 0 650nm (0.47A/W) (0.52A/W) VOLTAGE RESPONSIVITY vs RADIANT POWER Radiant Power (µW) O ut pu t V ol ta ge (V ) 0.01 0.1 10 100 1k1 10 1 0.1 0.01 0.001 R F = 1M Ω R F = 10 0kΩ R F = 10 kΩ R F = 10 MΩ λ = 650nm VOLTAGE RESPONSIVITY vs IRRADIANCE Irradiance (W/m2) O ut pu t V ol ta ge (V ) 0.001 0.01 1 10 1000.1 10 1 0.1 0.01 0.001 R F = 1M Ω R F = 10 0kΩ R F = 10 kΩ R F = 10 MΩ λ = 650nm DISTRIBUTION OF RESPONSIVITY Un its (% ) Responsivity (A/W) 0.45 60 50 40 30 20 10 0 0.46 0.47 0.48 0.49 0.5 Distribution Totals 100% λ = 650nm Laboratory Test Data RESPONSE vs INCIDENT ANGLE R el at iv e R es po ns e Incident Angle (°) 0 1.0 0.8 0.6 0.4 0.2 0 ±20 ±40 ±60 ±80 1.0 0.8 0.6 0.4 0.2 0 θ VOLTAGE OUTPUT RESPONSIVITY vs FREQUENCY R es po ns ivi ty (V /µW ) Frequency (Hz) 100 10 1 0.1 0.01 0.001 1k 10k 100k 1M RF = 10MΩ RF = 3.3MΩ RF = 1MΩ RF = 330kΩ CEXT = 30pF RF = 100kΩ CEXT = 90pF RF = 33kΩ CEXT = 180pF RF = 10kΩ CEXT = 350pF λ = 650nm 6 ® OPT301 TYPICAL PERFORMANCE CURVES At TA = +25°C, VS = ±15V, λ = 650nm, unless otherwise noted. SMALL-SIGNAL DYNAMIC RESPONSE LARGE-SIGNAL DYNAMIC RESPONSE 20 m V/ di v 2V /d iv 100µs/div 100µs/div QUIESCENT CURRENT vs TEMPERATURE Qu ies ce nt C ur re nt (m A) Temperature (°C) –75 0.6 0.5 0.4 0.3 0.2 0.1 0 –50 –25 0 25 50 75 100 125 VS = ±15V VS = ±2.25V Dice OUTPUT NOISE VOLTAGE vs MEASUREMENT BANDWIDTH Measurement Bandwidth (Hz) N oi se V ol ta ge (µ Vr ms ) 1 10 1k 10k 100k100 1000 100 10 1 0.1 R F = 10 MΩ R F = 1M Ω RF = 100kΩ CEXT = 90pF R F = 100 MΩ RF = 10kΩ CEXT = 350pF Dotted lines show noise beyond the signal bandwidth. NOISE EFFECTIVE POWER vs MEASUREMENT BANDWIDTH Measurement Bandwidth (Hz) N oi se E ffe ct ive P ow er (W ) 1 10 1k 10k 100k100 10–7 10–8 10–9 10–10 10–11 10–12 10–13 10–14 Dotted lines indicate noise measured beyond the signal bandwidth. λ = 650nm RF = 100M RF = 10M RF = 1M RF = 100k RF = 10k 6 7 ® OPT301 APPLICATIONS INFORMATION Figure 1 shows the basic connections required to operate the OPT301. Applications with high-impedance power supplies may require decoupling capacitors located close to the device pins as shown. Output is zero volts with no light and increases with increasing illumination. If your light source is focused to a small area, be sure that it is properly aimed to fall on the photodiode. If a narrowly focused light source were to miss the photodiode area and fall only on the op amp circuitry, the OPT301 would not perform properly. The large (0.090 x 0.090 inch) photodiode area allows easy positioning of narrowly focused light sources. The photodiode area is easily visible—it appears very dark compared to the surrounding active circuitry. The incident angle of the light source also affects the apparent sensitivity in uniform irradiance. For small incident angles, the loss in sensitivity is simply due to the smaller effective light gathering area of the photodiode (proportional to the cosine of the angle). At a greater incident angle, light is reflected and scattered by the side of the package. These effects are shown in the typical performance curve “Response vs Incident Angle.” DARK ERRORS The dark errors in the specification table include all sources. The dominant error source is the input offset voltage of the op amp. Photodiode dark current and input bias current of the op amp are approximately 2pA and contribute virtually no offset error at room temperature. Dark current and input bias current double for each 10°C above 25°C. At 70°C, the error current can be approximately 100pA. This would produce a 1mV offset with RF = 10MΩ. The OPT301 is useful with feedback resistors of 100MΩ or greater at room temperature. The dark output voltage can be trimmed to zero with the optional circuit shown in Figure 3. FIGURE 1. Basic Circuit Connections. Photodiode current, ID, is proportional to the radiant power or flux (in watts) falling on the photodiode. At a wavelength of 650nm (visible red) the photodiode Responsivity, RI, is approximately 0.45A/W. Responsivity at other wavelengths is shown in the typical performance curve “Responsivity vs Wavelength.” The typical performance curve “Output Voltage vs Radiant Power” shows the response throughout a wide range of radiant power. The response curve “Output Voltage vs Irradiance” is based on the photodiode area of 5.23 x 10–6m2. The OPT301’s voltage output is the product of the photodiode current times the feedback resistor, (IDRF). The internal feedback resistor is laser trimmed to 1MΩ ±2%. Using this resistor, the output voltage responsivity, RV, is approximately 0.45V/µW at 650nm wavelength. An external resistor can be used to set a different voltage responsivity. For values of RF less than 1MΩ, an external capacitor, CEXT, should be connected in parallel with RF (see Figure 2). This capacitor eliminates gain peaking and prevents instability. The value of CEXT can be read from the table in Figure 2. LIGHT SOURCE POSITIONING The OPT301 is 100% tested with a light source that uniformly illuminates the full area of the integrated circuit, including the op amp. Although all IC amplifiers are light-sensitive to some degree, the OPT301 op amp circuitry is designed to minimize this effect. Sensitive junctions are shielded with metal, and differential stages are cross-coupled. Furthermore, the photodiode area is very large relative to the op amp input circuitry making these effects negligible. FIGURE 2. Using External Feedback Resistor. EXTERNAL RF CEXT 100MΩ (1) 10MΩ (1) 1MΩ (1) 330kΩ 30pF 100kΩ 130pF 33kΩ 180pF 10kΩ 350pF NOTE: (1) No CEXT required. ID is proportional to light intensity (radiant power). 1MΩ OPT301 40pF 75Ω 2 8 3 5 4 1 VO –15V+15V 0.1µF 0.1µF VO = ID RF RF ID ID (0V) λ NOTE: Metal package is internally connected to common (Pin 8). 1MΩ OPT301 40pF 75Ω 8 3 5 4 1 VO = ID RF V– λ V+ RF CEXT 2 8 ® OPT301 When used with very large feedback resistors, tiny leakage currents on the circuit board can degrade the performance of the OPT301. Careful circuit board design and clean assembly procedures will help achieve best performance. A “guard trace” on the circuit board can help minimize leakage to the critical non-inverting input (pin 2). This guard ring should encircle pin 2 and connect to Common, pin 8. DYNAMIC RESPONSE Using the internal 1MΩ resistor, the dynamic response of the photodiode/op amp combination can be modeled as a simple R/C circuit with a –3dB cutoff frequency of 4kHz. This yields a rise time of approximately 90µs (10% to 90%). Dynamic response is not limited by op amp slew rate. This is demonstrated by the dynamic response oscilloscope photographs showing virtually identical large-signal and small-signal response. Dynamic response will vary with feedback resistor value as shown in the typical performance curve “Voltage Output Responsivity vs Frequency.” Rise time (10% to 90%) will vary according to the –3dB bandwidth produced by a given feedback resistor value— where: tR is the rise time (10% to 90%) fC is the –3dB bandwidth LINEARITY PERFORMANCE Current output of the photodiode is very linear with radiant power throughout a wide range. Nonlinearity remains below approximately 0.02% up to 100µA photodiode current. The photodiode can produce output currents of 1mA or greater with high radiant power, but nonlinearity increases to several percent in this region. This excellent linearity at high radiant power assumes that the full photodiode area is uniformly illuminated. If the light source is focused to a small area of the photodiode, nonlinearity will occur at lower radiant power. NOISE PERFORMANCE Noise performance of the OPT301 is determined by the op amp characteristics in conjunction with the feedback components and photodiode capacitance. The typical performance curve “Output Noise Voltage vs Measurement Bandwidth” shows how the noise varies with RF and measured bandwidth (1Hz to the indicated frequency). The signal bandwidth of the OPT301 is indicated on the curves. Noise can be reduced by filtering the output with a cutoff frequency equal to the signal bandwidth. Output noise increases in proportion to the square-root of the feedback resistance, while responsivity increases linearly with feedback resistance. So best signal-to-noise ratio is achieved with large feedback resistance. This comes with the trade-off of decreased bandwidth. The noise performance of a photodetector is sometimes characterized by Noise Effective Power (NEP). This is the radiant power which would produce an output signal equal to the noise level. NEP has the units of radiant power (watts). The typical performance curve “Noise Effective Power vs Measurement Bandwidth” shows how NEP varies with RF and measurement bandwidth. t R » 0. 35 f C (1) FIGURE 3. Dark Error (Offset) Adjustment Circuit. 1MΩ OPT301 40pF 75Ω 2 8 3 5 4 1 VO V– λ V+ 0.01µF 500Ω V+ V– 100µA 1/2 REF200 100Ω 100Ω 100µA 1/2 REF200 Adjust dark output for 0V. Trim Range: ±7mV FIGURE 4. Responsivity (Gain) Adjustment Circuit. 1MΩ OPT301 40pF 75Ω 2 8 3 5 4 1 VO V– λ V+ 10kΩ 5kΩ Gain Adjustment +50%; –0% RF 6 9 ® OPT301 FIGURE 5. “T” Feedback Network. FIGURE 7. Differential Light Measurement. FIGURE 8. Current Output Circuit. Bandwidth is reduced to 2.8kHz due to additional photodiode capacitance. FIGURE 6. Summing Output of Two OPT301s. 1MΩ OPT301 40pF 75Ω 2 8 3 5 4 1 V– λ V+ R1 19kΩ RF R2 1kΩ VO = ID RF R1 + R2 R2 Advantages: High gain with low resistor values. Less sensitive to circuit board leakage. Disadvantage: Higher offset and noise than by using high value for RF. 1MΩ OPT301 40pF 75Ω 2 8 3 5 4 1 R1 1kΩ –15V λ +15V RF ID IO ≤ 5mA IO = ID 1 + RF R1 1MΩ OPT301 40pF 75Ω 2 8 3 5 4 1 NC λ RF 1MΩ OPT301 40pF 75Ω 2 8 3 5 4 1 VO V– λ V+ RF 8 This OPT301 used as photodiode, only. NC VO = (ID2 – ID1) RF ID1 ID21MΩ OPT301 40pF 75Ω 2 8 3 5 4 1 VO = ID1 RF1 + ID2 RF2 V– λ V+ RF1 1MΩ OPT301 40pF 75Ω 2 8 3 5 4 1 VO = ID2 RF2 V– λ V+ RF2 Max linear input voltage (V+) –0.6V typ 10 ® OPT301 FIGURE 9. Single Power Supply Operation. FIGURE 10. Output Filter to Reduce Noise. FIGURE 11. Differential Light Measurement. 1MΩ OPT301 40pF 75Ω 2 8 3 5 4 1 VO = IDRF VZ λ V+ RF 0.1µF (pesudo-ground) – + VZ(1) 3.3V NOTE: (1) Zener diode or other shunt regulator. 5kΩ 1MΩ OPT301 40pF 75Ω 2 8 3 5 4 1 VO V– λ V+ RF1 10nF Output filter reduces output noise from 250µV to 195µV. 1MΩ OPT301 40pF 75Ω 2 8 3 5 4 1 VO1 = ID1 RF1 V– λ V+ RF1 1MΩ OPT301 40pF 75Ω 2 8 3 5 4 1 VO2 = ID2 RF2 V– λ V+ RF2 100kΩ INA106 6 VO = 10 (VO2 – VO1) 100kΩ 10kΩ 10kΩ 1 5 8 3 2 G = 10 Difference Measurement 3 10 7 VO = K logLOG100 VO1 VO2 Log of Ratio Measurement (Absorbance) 14 1100kΩ 100kΩ 1nFCC 6 11 ® OPT301 A1 VO C1 0.1µF R2 1MΩ R1 1MΩ C2 0.1µF R3 100kΩ 1MΩ R3(2piR2C2) f –3dB = 20dB/decade 1MΩ OPT301 40pF 75Ω 2 8 5 4 λ FIGURE 12. DC Restoration Rejects Unwanted Steady-State Background Light. FIGURE 13. 4-20mA Current-Loop Transmitter. 1MΩ OPT301 40pF 75Ω 2 8 3 5 4 λ 1 4-20mA (4mA Dark) 10V to 36V 100µA 1/2 REF200 100µA 1/2 REF200 20kΩ R2 65Ω IN4148 2N2222 R1 22.5kΩ Calculations shown provide a dark output of 4mA. Output is 20mA at a photodiode current of ID max. Values shown are for ID max max = 1µA. R1 = – 994,000Ω 1.014 X 106 (1 – 2500 ID max) R2 = – 26,000Ω 26,000 (1 – 2500 ID max) PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Qty Eco Plan (2) Lead/Ball Finish MSL Peak Temp (3) OPT301M NRND TO LMD 8 20 Green (RoHS & no Sb/Br) AU N / A for Pkg Type (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to sup