OPT201KP

® FPO 70% OPT201 INTEGRATED PHOTODIODE AND AMPLIFIER FEATURES q PHOTODIODE SIZE: 0.090 x 0.090 inch (2.29 x 2.29mm) q 1MΩ FEEDBACK RESISTOR q HIGH RESPONSIVITY: 0.45A/W (650nm) q LOW DARK ERRORS: 2mV q BANDWIDTH: 4kHz q WIDE SUPPLY RANGE: ±2.25 to ±18V q LOW QUIESCENT CURRENT: 400µA q TRANSPARENT 8-PIN DIP DESCRIPTION The OPT201 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 FETinput 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 designs such as leakage current errors, noise pick-up and gain peaking due to stray capacitance. The OPT201 operates over a wide supply range (±2.25 to ±18V) and supply current is only 400µA. It is packaged in a transparent plastic 8-pin DIP, specified for the 0°C to 70°C temperature range. APPLICATIONS q q q q q MEDICAL INSTRUMENTATION LABORATORY INSTRUMENTATION POSITION AND PROXIMITY SENSORS PHOTOGRAPHIC ANALYZERS SMOKE DETECTORS SPECTRAL RESPONSIVITY Green Yellow Blue Ultraviolet Red 4 Voltage Output (V/µW) 1MΩ 40pF 0.5 0.4 0.3 0.2 0.1 Using Internal 1MΩ Resistor 0.5 0.4 0.3 0.2 0.1 0 75Ω λ OPT201 8 1 V+ 3 V– 5 VO 0 100 200 300 400 500 600 700 800 900 1000 1100 Wavelength (nm) 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 • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132 ® © 1993 Burr-Brown Corporation PDS-1180A PDS-1180B 1 Printed in U.S.A. January, 1995 OPT201 Photodiode Responsivity (A/W) 2 Infrared SPECIFICATIONS ELECTRICAL TA = +25°C, VS = ±15V, λ = 650nm, internal 1MΩ feedback resistor, unless otherwise noted. OPT201KP PARAMETER RESPONSIVITY Photodiode Current Voltage Output Unit-to-Unit Variation Nonlinearity(1) vs Temperature Photodiode Area CONDITIONS 650nm 650nm 650nm FS Output = 10V (0.090 x 0.090in) (2.29 x 2.29mm) MIN TYP 0.45 0.45 ±20 0.02 200 0.008 5.2 ±0.5 ±10 10 160 1 ±0.5 50 ±2 100 MAX UNITS A/W V/µW % % of FS ppm/°C in2 mm2 DARK ERRORS, RTO(2) Offset Voltage, Output vs Temperature vs Power Supply Voltage Noise RESISTOR—1MΩ Internal Resistance Tolerance vs Temperature FREQUENCY RESPONSE Bandwidth, Large or Small-Signal, –3dB Rise Time, 10% to 90% Settling Time, 1% 0.1% 0.01% Overload Recovery Time VS = ±2.25V to ±18V Measured BW = 0.1 to 100kHz mV µV/°C µV/V µVrms MΩ % ppm/°C kHz µs µs µs µs µs µs µs V V nF mA V V mA °C °C °C/W ±2 FS to Dark FS to Dark FS to Dark 100% overdrive, VS = ±15V 100% overdrive, VS = ±5V 100% overdrive, VS = ±2.25V RL = 10kΩ RL = 5kΩ (V+) – 1.25 (V+) – 2 4 90 400 500 800 150 380 800 OUTPUT Voltage Output Capacitive Load, Stable Operation Short-Circuit Current POWER SUPPLY Specified Operating Voltage Operating Voltage Range Quiescent Current TEMPERATURE RANGE Specification, Operating Storage Thermal Resistance, θJA (V+) – 0.65 (V+) – 1 10 ±18 ±15 ±0.4 ±2.25 IO = 0 0 –25 ±18 ±0.5 +70 +85 100 NOTES: (1) Deviation in percent of full scale from best-fit straight line. (2) Referred to Output. Includes all error sources. PHOTODIODE SPECIFICATIONS TA = +25°C, unless otherwise noted. Photodiode of OPT201 PARAMETER Photodiode Area Current Responsivity Dark Current vs Temperature Capacitance NOTE: (1) Voltage Across Photodiode. CONDITIONS (0.090 x 0.090in) (2.29 x 2.29mm) 650nm VD = 0V(1) VD = 0V(1) MIN TYP 0.008 5.1 0.45 500 doubles every 10°C 4000 MAX UNITS in2 mm2 A/W fA pF ® OPT201 2 SPECIFICATIONS ELECTRICAL (CONT) Op Amp Section of OPT201(1) OPT201 Op Amp TA = +25°C, VS = ±15V, unless otherwise noted. PARAMETER INPUT Offset Voltage vs Temperature vs Power Supply Input Bias Current vs Temperature NOISE Input Voltage Noise Voltage Noise Density, f=10Hz f=100Hz f=1kHz Current Noise Density, f=1kHz INPUT VOLTAGE RANGE Common-mode Input Range Common-mode Rejection INPUT IMPEDANCE Differential Common-mode OPEN-LOOP GAIN Open-loop Voltage Gain FREQUENCY RESPONSE Gain-Bandwidth Product Slew Rate Settling Time 0.1% 0.01% OUTPUT Voltage Output Short-Circuit Current POWER SUPPLY Specified Operating Voltage Operating Voltage Range Quiescent Current CONDITIONS MIN TYP ±0.5 ±5 10 1 doubles every 10°C MAX UNITS mV µV/°C µV/V pA VS = ±2.25V to ±18V 30 25 15 0.8 ±14.4 106 nV/ nV/ nV/ fA/ Hz Hz Hz Hz V dB Ω||pF Ω||pF dB 1012||3 1012||3 120 380 0.5 4 5 RL = 10kΩ RL = 5kΩ kHz V/µs µs µs V V mA (V+) – 1.25 (V+) – 2 (V+) – 0.65 (V+) – 1 ±18 ±15 ±0.4 ±2.25 IO = 0 ±18 ±0.5 V V mA NOTE: (1) Op amp specifications provided for information and comparison only. 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. ® 3 OPT201 DICE INFORMATION PAD 1 2 3 4 5 6 7 8A, 8B FUNCTION V+ –In V– 1MΩ Feedback Output NC NC Common Photodiode Area 0.090 x 0.090 inch 2.29 x 2.29 mm NC: No Connection. Pads 8A and 8B must both be connected to common. Substrate Bias: The substrate is electrically connected to internal circuitry. Do not make electrical connection to the substrate. MECHANICAL INFORMATION MILS (0.001") Die Size Die Thickness Min. Pad Size Backing 154 x 120 ±5 20 ±3 4x4 MILLIMETERS 3.91 x 3.05 ±0.13 0.51 ±0.08 0.1 x 0.1 None OPT201 DIE TOPOGRAPHY PIN CONFIGURATION TOP VIEW ELECTROSTATIC DISCHARGE SENSITIVITY 8 7 Common NC NC Output V+ –In V– 1MΩ Feedback 1 2 (1) (2) 3 4 6 5 This integrated circuit can be damaged by ESD. Burr-Brown recommends that all integrated circuits be handled with appropriate 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. SPECIAL PACKAGE INFORMATION To provide consistent optical properties, the OPT201 is not marked on the top of the 8-pin plastic DIP. It is identified by a special marking “YY” on the package bottom next to pin 8. See “Pin Configuration Diagram.” The fire-retardant fillers used in black plastic packages are not compatible with the clear molding compound used for the OPT201KP. The OPT201KP cannot meet the flamability test, UL-94. NOTE: (1) Photodiode location. (2) Model identification mark "YY" on package bottom, next to pin 8. ABSOLUTE MAXIMUM RATINGS Supply Voltage ................................................................................... ±18V Input Voltage Range (Common Pin) .................................................... ±VS Output Short-Circuit (to ground) ............................................... Continuous Operating Temperature ..................................................... –25°C to +85°C Storage Temperature ........................................................ –25°C to +85°C Junction Temperature ...................................................................... +85°C Lead Temperature (soldering, 10s) ................................................ +300°C (Vapor-Phase Soldering Not Recommended) PACKAGE INFORMATION(1) MODEL OPT201KP PACKAGE 8-Pin DIP PACKAGE DRAWING NUMBER 006-1 NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix D of Burr-Brown IC Data Book. ® OPT201 4 TYPICAL PERFORMANCE CURVES At TA = +25°C, VS = ±15V, λ = 650nm, unless otherwise noted. NORMALIZED SPECTRAL RESPONSIVITY 1.0 Normalized Current or Voltage Output 10 VOLTAGE RESPONSIVITY vs RADIANT POWER 0.8 (0.48A/W) Output Voltage (V) 650nm (0.45A/W) 1 0.6 RF 0.1 = 10 Ω M Ω 1M = 10 0k RF = Ω kΩ λ = 650nm 0.4 RF 0.01 0.2 0.001 RF = 10 0 100 200 300 400 500 600 700 800 900 1000 1100 Wavelength (nm) 0.01 0.1 1 10 100 1k Radiant Power (µW) VOLTAGE RESPONSIVITY vs IRRADIANCE 10 VOLTAGE OUTPUT RESPONSIVITY vs FREQUENCY 10 RF = 10MΩ RF = 3.3MΩ RF = 1MΩ λ = 650nm RF 0.1 = 10 M Responsivity (V/µW) Output Voltage (V) 1 Ω Ω 10 Ω 0k 10 kΩ λ = 650nm 1 RF 0.01 = 1M 0.1 RF = 330kΩ CEXT = 30pF RF = 100kΩ CEXT = 90pF RF = RF 0.001 0.001 0.01 0.1 = 0.01 RF = 33kΩ CEXT = 180pF RF = 10kΩ CEXT = 350pF 0.001 1 10 100 100 1k 10k Frequency (Hz) 100k 1M Irradiance (W/m2) DISTRIBUTION OF RESPONSIVITY 60 50 40 Units (%) RESPONSE vs INCIDENT ANGLE 1.0 1.0 θX 0.8 Relative Response λ = 650nm Distribution Totals 100% θY θX θY 0.8 0.6 0.6 30 20 10 0 0 0.1 0.2 0.3 0.4 0.5 0.6 Responsitity (A/W) 0.4 0.4 0.2 0.2 0 0 ±20 ±40 Incident Angle (°) ±60 ±80 0 ® 5 OPT201 TYPICAL PERFORMANCE CURVES At TA = +25°C, VS = ±15V, λ = 650nm, unless otherwise noted. (CONT) QUIESCENT CURRENT vs TEMPERATURE 0.6 0.5 Quiescent Current (mA) 1000 OUTPUT NOISE VOLTAGE vs MEASUREMENT BANDWIDTH Dotted lines show noise beyond the signal bandwidth. Noise Voltage (µVrms) VS = ±15V 100 0.4 0.3 10 VS = ±2.25V 0.2 0.1 0 –75 –50 –25 0 25 50 75 Dice RF 0 =1 Ω 0M RF =1 Ω 0M RF = 1M Ω 1 0.1 RF = 100kΩ CEXT = 90pF 1 10 100 RF = 10kΩ CEXT = 350pF 100 125 1k 10k 100k Temperature (°C) Measurement Bandwidth (Hz) SMALL-SIGNAL DYNAMIC RESPONSE LARGE-SIGNAL DYNAMIC RESPONSE 20mV/div 2V/div 100µs/div 100µs/div NOISE EFFECTIVE POWER vs MEASUREMENT BANDWIDTH 10–7 Dotted lines indicate noise measured beyond the signal bandwidth. λ = 650nm 10k 100k 1M 10–10 10M 10–11 100M 10–12 10–8 Noise Effective Power (W) 10–9 10–13 10–14 1 10 100 1k 10k 100k Measurement Bandwidth (Hz) ® OPT201 6 APPLICATIONS INFORMATION Figure 1 shows the basic connections required to operate the OPT201. 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. 2 1MΩ (0V) 40pF RF ID 4 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 OPT201 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 diffracted 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 in the 2pA range 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 OPT201 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. CEXT ID is proportional to light intensity (radiant power). λ ID 75Ω 5 VO VO = ID R F OPT201 8 1 0.1µF 0.1µF +15V –15V 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 OPT201’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 substituted, added in series, or in parallel with the internal resistor 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 OPT201 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 OPT201 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. RF 2 1MΩ 40pF 4 75Ω λ OPT201 8 1 V+ 3 V– 5 VO = ID RF EXTERNAL RF 100MΩ 10MΩ 1MΩ 330kΩ 100kΩ 33kΩ 10kΩ CEXT (1) (1) (1) 30pF 130pF 180pF 350pF NOTE: (1) No CEXT required. FIGURE 2. Using External Feedback Resistor. ® 7 OPT201 When used with very large feedback resistors, tiny leakage currents on the circuit board can degrade the performance of the OPT201. Careful circuit board design and clean assembly procedures will help achieve best performance. A “guard ring” 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— t R ≈ 0. 35 (1) f C 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 very linear performance 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 OPT201 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 OPT201 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. 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 2 2 1MΩ 40pF 4 1MΩ 40pF RF 4 Gain Adjustment +50%; –0% 75Ω V+ 100µA 1/2 REF200 100Ω 100Ω 100µA 1/2 REF200 75Ω λ OPT201 8 500Ω 1 V+ 3 V– 5 λ VO 5 VO 5kΩ 10kΩ OPT201 8 1 V+ 3 V– 0.01µF FIGURE 4. Responsivity (Gain) Adjustment Circuit. Adjust dark output for 0V. Trim Range: ±7mV V– FIGURE 3. Dark Error (Offset) Adjustment Circuit. ® OPT201 8 2 1MΩ 40pF VO = 75Ω 5 R1 19kΩ R2 1kΩ RF 4 This OPT201 used as photodiode, only. 2 1MΩ RF 4 NC R1 + R2 R2 ID RF 40pF λ OPT201 8 1 V+ 3 V– 75Ω λ OPT201 ID1 8 1 3 5 NC 2 Advantages: High gain with low resistor values. Less sensitive to circuit board leakage. Disadvantage: Higher offset and noise than by using high value for R F. 40pF 1MΩ RF 4 FIGURE 5. “T” Feedback Network. 75Ω λ 2 1MΩ 40pF RF1 4 5 VO VO = (ID2 – ID1) RF OPT201 ID2 8 1 V+ 3 V– Bandwidth is reduced to 2.8kHz due to additional photodiode capacitance. 75Ω λ OPT201 8 1 V+ Max linear input voltage (V+) –0.6V typ 2 1MΩ 40pF RF2 3 V– 5 VO = ID1 RF1 + ID2 RF2 FIGURE 7. Differential Light Measurement. 2 1MΩ 40pF RF 4 75Ω 4 λ OPT201 ID 8 1 +15V 3 –15V 5 R1 1kΩ IO ≤ 5mA 75Ω λ OPT201 8 1 V+ 3 V– 5 VO = ID2 RF2 IO = ID 1 + RF R1 FIGURE 6. Summing Output of Two OPT201s. FIGURE 8. Current Output Circuit. ® 9 OPT201 2 1MΩ 40pF RF 4 2 1MΩ 40pF RF1 4 Output filter reduces output noise from 250µV to 195µV. 75Ω + OPT201 VO = IDRF – 75Ω λ 8 VZ 3.3V (1) 5 λ OPT201 8 1 V+ 3 V– 5 VO 1 3 VZ (pesudo-ground) 0.1µF 10nF 5kΩ FIGURE 10. Output Filter to Reduce Noise. V+ NOTE: (1) Zener diode or other shunt regulator. FIGURE 9. Single Power Supply Operation. 2 1MΩ 40pF RF1 4 10kΩ 2 75Ω INA106 100kΩ 5 Difference Measurement VO = 10 (VO2 – VO1) λ OPT201 8 1 V+ 3 V– 5 VO1 = ID1 RF1 3 10kΩ 100kΩ 6 1 G = 10 2 1MΩ 40pF RF2 4 100kΩ 100kΩ 1 14 LOG100 7 10 Log of Ratio Measurement (Absorbance) V VO = K log O1 VO2 3 75Ω λ OPT201 8 1 V+ 3 V– 5 VO2 = ID2 RF2 CC 1nF FIGURE 11. Differential Light Measurement. ® OPT201 10 3.3nF +15V 2 REF102 4 10V 6 11kΩ 0.03µF IN4148 10kΩ 270Ω 100kΩ OPA627 LED 2 1MΩ 40pF RF 4 75Ω λ OPT201 8 1 +15V 3 –15V 5 LED Glass Microscope Slide Approximately 92% light available for application. ≈ 8% OPT201 FIGURE 12. LED Output Regulation Circuit. 1/2 REF200 100µA 100µA 2 1MΩ 40pF 2N2222 75Ω 1 4 10V to 36V 1/2 REF200 λ OPT201 8 3 5 20kΩ 4-20mA (4mA Dark) IN4148 R1 22.5kΩ R2 65Ω Values 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 = 1.014 X 106 (1 – 2500 ID max) 26,000 (1 – 2500 ID max) – 994,000Ω – 26,000Ω R2 = FIGURE 13. 4-20mA Current-Loop Transmitter. ® 11 OPT201