® OPT202 FPO PHOTODIODE WITH ON-CHIP AMPLIFIER FEATURES DESCRIPTION ● BANDWIDTH: 50kHz ● PHOTODIODE SIZE: 0.090 x 0.090 inch (2.29 x 2.29mm) ● 1MΩ FEEDBACK RESISTOR ● HIGH RESPONSIVITY: 0.45A/W (650nm) The OPT202 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. ● LOW DARK ERRORS: 2mV ● WIDE SUPPLY RANGE: ±2.25 to ±18V ● LOW QUIESCENT CURRENT: 400µA 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. ● TRANSPARENT 8-PIN DIP AND 5-PIN SIP ● HERMETIC 8-PIN CERAMIC DIP The OPT202 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 or 5-pin SIP, specified for the 0°C to +70°C temperature range as well as a hermetic ceramic 8-pin DIP with a glass window, specified for the –40°C to +85°C temperature range. APPLICATIONS ● MEDICAL INSTRUMENTATION ● LABORATORY INSTRUMENTATION ● POSITION AND PROXIMITY SENSORS ● PHOTOGRAPHIC ANALYZERS ● SMOKE DETECTORS 3pF 175Ω λ 5 (5) OPT202 (1) 8 (2) 1 VO Infrared 0.5 Using Internal 1MΩ Resistor 0.4 0.4 0.3 0.3 0.2 0.2 0.1 0.1 Photodiode Responsivity (A/W) 4 (4) Red Ultraviolet 0.5 Voltage Output (V/µW) 1MΩ Blue 2 (Pin available on DIP only) Green Yellow SPECTRAL RESPONSIVITY (3) 3 V+ 0 V– (SIP) 100 DIP 200 300 400 500 600 0 700 800 900 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 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 ® PDS-1200E 1 OPT202 SPECIFICATIONS ELECTRICAL At TA = +25°C, VS = ±15V, λ = 650nm, internal 1MΩ feedback resistor, unless otherwise noted. OPT202P, W, G PARAMETER CONDITIONS RESPONSIVITY Photodiode Current Voltage Output vs Temperature Unit-to-Unit Variation Nonlinearity(1) Photodiode Area DARK ERRORS, RTO(2) Offset Voltage, Output: P, W Packages G Package vs Temperature vs Power Supply Voltage Noise MIN 650nm 650nm 650nm FS Output = 10V (0.090 x 0.090in) (2.29 x 2.29mm) 0.45 0.45 100 ±5 0.01 0.008 5.2 VS = ±2.25V to ±18V Measured BW = 0.1Hz to 100kHz ±0.5 ±0.5 ±10 10 1 RESISTOR—1MΩ Internal Resistance Tolerance: P, G Packages W Package 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 (to 1%) OUTPUT Voltage Output 1 ±0.5 ±0.5 50 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 Capacitive Load, Stable Operation Short-Circuit Current POWER SUPPLY Specified Operating Voltage Operating Voltage Range Quiescent Current TYP ±2.25 VO = 0 TEMPERATURE RANGE Specification; P, W Packages G Package Operating, P, W Packages G Package Storage P, W Packages G Package Thermal Resistance, θJA ±2 ±3 100 ±2 mV mV µV/°C µV/V mVr ms MΩ % % ppm/°C (V+) – 1 (V+) – 1.5 10 ±18 V V nF mA ±15 ±400 ±18 ±500 +70 +85 +70 +125 +85 +125 100 2 A/W V/µW ppm/°C % % of FS in2 mm2 kHz µs µs µs µs µs µs µs NOTES: (1) Deviation in percent of full scale from best-fit straight line. (2) Referred to Output. Includes all error sources. OPT202 UNITS 50 10 10 20 40 44 100 240 0 –40 0 –55 –25 –55 ® MAX V V µA °C °C °C °C °C °C °C/W SPECIFICATIONS (CONT) Op Amp Section of OPT202(1) ELECTRICAL At TA = +25°C, VS = ±15V, unless otherwise noted. OPT202 Op Amp PARAMETER INPUT Offset Voltage vs Temperature vs Power Supply Input Bias Current vs Temperature CONDITIONS MIN TYP MAX UNITS ±0.5 ±5 10 1 doubles every 10°C mV µV/°C µV/V pA 30 25 15 0.8 nV/√Hz nV/√Hz nV/√Hz fA/√Hz INPUT VOLTAGE RANGE Common-Mode Input Range Common-Mode Rejection ±14.4 106 V dB INPUT IMPEDANCE Differential Common-Mode 1012||3 1012||3 Ω || pF Ω || pF OPEN-LOOP GAIN Open-Loop Voltage Gain 120 dB FREQUENCY RESPONSE Gain-Bandwidth Product Slew Rate Settling Time 0.1% 0.01% 16 6 4 5 MHz V/µs µs µs (V+) – 1 (V+) – 1.5 ±18 V V mA VS = ±2.25V to ±18V NOISE Input Voltage Noise Voltage Noise Density, f = 10Hz f = 100Hz f = 1kHz Current Noise Density, f = 1kHz OUTPUT Voltage Output RL = 10kΩ RL = 5kΩ (V+) – 1.25 (V+) – 2 Short-Circuit Current POWER SUPPLY Specified Operating Voltage Operating Voltage Range Quiescent Current ±2.25 IO = 0 ±15 ±400 ±18 ±500 V V µA MAX UNITS NOTE: (1) Op amp specifications provided for information and comparison only. PHOTODIODE SPECIFICATIONS At TA = +25°C, unless otherwise noted. Photodiode of OPT202 PARAMETER Photodiode Area Current Responsivity Dark Current vs Temperature Capacitance CONDITIONS MIN (0.090 x 0.090in) (2.29 x 2.29mm) 650nm VD = 0V(1) TYP in2 mm2 A/W fA 0.008 5.2 0.45 500 doubles every 10°C 600 VD = 0V(1) pF NOTE: (1) Voltage Across Photodiode. 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 OPT202 ELECTROSTATIC DISCHARGE SENSITIVITY PIN CONFIGURATIONS Top View DIP V+ 1 –In 2 8 Common 7 NC 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. (1) V– 3 6 NC 1MΩ Feedback 4 5 Output 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. NOTE: (1) Photodiode location. Top View SIP Common 1 V+ 2 V– 3 1MΩ Feedback 4 Output 5 (1) MOISTURE SENSITIVITY AND SOLDERING Clear plastic does not contain the structural-enhancing fillers used in black plastic molding compound. As a result, clear plastic is more sensitive to environmental stress than black plastic. This can cause difficulties if devices have been stored in high humidity prior to soldering. The rapid heating during soldering can stress wire bonds and cause failures. Prior to soldering, it is recommended that plastic devices be baked-out at 85°C for 24 hours. ABSOLUTE MAXIMUM RATINGS Supply Voltage ................................................................................... ±18V Input Voltage Range (Common Pin) .................................................... ±VS Output Short-Circuit (to ground) ............................................... Continuous Operating Temperature: P, W ........................................... –25°C to +85°C G ............................................. –55°C to +125°C Storage Temperature: P, W ........................................... –25°C to +85°C G ............................................. –55°C to +125°C Junction Temperature: P, W .......................................................... +85°C G ............................................................. +150°C Lead Temperature (soldering, 10s) ................................................ +300°C (Vapor-Phase Soldering Not Recommended on Plastic Packages) The fire-retardant fillers used in black plastic are not compatible with clear molding compound. The OPT202 plastic packages cannot meet flammability test, UL-94. PACKAGE INFORMATION PRODUCT PACKAGE PACKAGE DRAWING NUMBER(1) OPT202P OPT202W OPT202G 8-Pin Plastic DIP 5-Pin Plastic SIP 8-Pin Ceramic DIP 006-1 321 161-1 NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book. ® OPT202 4 TYPICAL PERFORMANCE CURVES At TA = +25°C, VS = ±15V, λ = 650nm, unless otherwise noted. NORMALIZED SPECTRAL RESPONSIVITY VOLTAGE RESPONSIVITY vs RADIANT POWER 10 (0.48A/W) 0.8 650nm (0.45A/W) Output Voltage (V) Normalized Current or Voltage Output 1.0 0.6 0.4 Ω M 1 RF = 0.1 10 RF = Ω 1M Ω 0k RF = 10 λ = 650nm 0.01 0.2 0.001 0 100 200 300 400 500 600 700 800 900 1000 1100 0.01 0.1 Wavelength (nm) 1 10 100 VOLTAGE RESPONSIVITY vs IRRADIANCE VOLTAGE OUTPUT RESPONSIVITY vs FREQUENCY 10 10 RF = 10MΩ λ = 650nm Ω Responsivity (V/µW) Output Voltage (V) RF = 3.3MΩ 1 M RF = 10 Ω 0.1 RF = 1M RF 0.01 Ω 0k = 10 λ = 650nm 0.001 RF = 1MΩ 1 0.1 RF = 330kΩ CEXT = 3pF 0.01 0.001 0.001 0.01 0.1 1 10 100 1k 100 10k Irradiance (W/m2) RESPONSE vs INCIDENT ANGLE SIP Package 1.00 0.90 θX θY 0.8 θY 0.80 Relative Output θX 0.6 0.6 θX 0.4 Plastic DIP Package 10M 1M RESPONSE vs INCIDENT ANGLE 1.0 0.8 100k Frequency (Hz) 1.0 Relative Response 1k Radiant Power (µW) θY 0.4 0.2 0.2 0.70 θX and θY 0.60 0.50 θX 0.40 Ceramic DIP Package θY 0.30 02.0 0.10 0 0 ±20 ±40 ±60 0 ±80 0 0 Incident Angle (°) 10 20 30 40 50 60 70 80 90 Angle of Incidence ® 5 OPT202 TYPICAL PERFORMANCE CURVES (CONT) At TA = +25°C, VS = ±15V, λ = 650nm, unless otherwise noted. OUTPUT NOISE VOLTAGE vs MEASUREMENT BANDWIDTH QUIESCENT CURRENT vs TEMPERATURE 10–2 0.6 Dotted lines indicate noise measured beyond the signal bandwidth. 10–3 VS = ±15V Noise Voltage (Vrms) Quiescent Current (mA) 0.5 0.4 0.3 VS = ±2.25V Dice 0.2 RF = 10MΩ 10–4 RF = 100MΩ 10–5 RF = 100kΩ RF = 1MΩ 10–6 0.1 0 10–7 –50 –75 –25 0 25 50 75 100 125 1 10 100 Temperature (°C) SMALL-SIGNAL RESPONSE 10k 100k 1M 2V/div 20mV/div LARGE-SIGNAL RESPONSE 10µs/div 10µs/div NOISE EFFECTIVE POWER vs MEASUREMENT BANDWIDTH DISTRIBUTION OF RESPONSIVITY 10–7 60 Dotted lines indicate noise measured beyond the signal bandwidth. λ = 650nm RF = 100kΩ 50 λ = 650nm RF = 1MΩ 10–9 RF = 10MΩ 10–10 RF = 100MΩ 10–11 40 Units (%) 10–8 Noise Effective Power (W) 1k Frequency (Hz) Distribution Totals 100% 30 Laboratory Test Data 20 10 0 0.43 10–12 0.44 0.45 0.46 Responsivity (A/W) 10–13 10–14 1 10 100 1k 10k 100k 1M Frequency (Hz) ® OPT202 6 0.47 0.48 APPLICATIONS INFORMATION some degree, the OPT202 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 1 shows the basic connections required to operate the OPT202. 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 OPT202 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. (Pin available on DIP only) 1MΩ ID is proportional to light intensity (radiant power). λ (0V) RF ID 3pF 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 diffused by the side of the package. These effects are shown in the typical performance curve “Response vs Incident Angle.” 175Ω ID VO V O = I D RF OPT202 0.1µF 0.1µF +15V –15V FIGURE 1. Basic Circuit Connections. For RF > 1MΩ 1MΩ 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.” RF = REXT + 1MΩ REXT 175Ω λ VO = I D R F 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. OPT202 V+ V– CEXT The OPT202’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. For RF < 1MΩ RF = REXT || 1MΩ 2 REXT 1MΩ 4 3pF An external resistor can be connected to set a different voltage responsivity. Best dynamic performance is achieved by connecting REXT in series (for RF > 1MΩ), or in parallel (for RF < 1MΩ), with the internal resistor as shown in Figure 2. Placing the external resistor in parallel with the internal resistor requires the DIP package. These connections take advantage of on-chip capacitive guarding of the internal resistor, which improves dynamic performance. 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. 175Ω λ 5 V O = I D RF OPT202 8 1 3 V+ LIGHT SOURCE POSITIONING The OPT202 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 Circuit Requires DIP Package V– EQUIVALENT RF CEXT 100MΩ 10MΩ 1MΩ 330kΩ ≤100kΩ (1) (1) (1) 2pF (2) NOTES: (1) No CEXT required. (2) Not recommended due to possible op amp instability. FIGURE 2. Using External Feedback Resistor. ® 7 OPT202 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 OPT202 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. simple R/C circuit with a –3dB cutoff frequency of 50kHz. This yields a rise time of approximately 10µs (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 where: tR is the rise time (10% to 90%) fC is the –3dB bandwidth When used with very large feedback resistors, tiny leakage currents on the circuit board can degrade the performance of the OPT202. 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. NOISE PERFORMANCE Noise performance of the OPT202 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 OPT202 is indicated on the curves. Noise can be reduced by filtering the output with a cutoff frequency equal to the signal bandwidth. 1MΩ 3pF V+ 175Ω λ 100µA 1/2 REF200 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. VO OPT202 V+ 100Ω V– 500Ω 100Ω 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. 0.01µF 100µA 1/2 REF200 Adjust dark output for 0V. Trim Range: ±7mV V– FIGURE 3. Dark Error (Offset) Adjustment Circuit. LINEARITY PERFORMANCE Current output of the photodiode is very linear with radiant power throughout a wide range. Nonlinearity remains below approximately 0.01% up to 100µA photodiode current. The photodiode can produce output currents of 10mA or greater with high radiant power, but nonlinearity increases to several percent in this region. 1MΩ 3pF Gain Adjustment +50%; –0% 175Ω λ 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. VO OPT202 V+ DYNAMIC RESPONSE Using the internal 1MΩ resistor, the dynamic response of the photodiode/op amp combination can be modeled as a V– 5kΩ 10kΩ FIGURE 4. Responsivity (Gain) Adjustment Circuit. ® OPT202 RF 8 1MΩ 1MΩ RF 3pF VO = R1 + R2 R2 3pF ID RF 175Ω 175Ω λ λ + R1 19kΩ OPT202 V+ RF OPT202 R2 1kΩ V– VO = IDRF – VZ(1) VZ 5kΩ 3.3V (pesudo-ground) 0.1µF 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. V+ NOTE: (1) Zener diode or other shunt regulator. FIGURE 5. “T” Feedback Network. FIGURE 7. Single Power Supply Operation. 1MΩ C2 0.1µF RF R2 1MΩ 3pF A1 175Ω λ R3 100kΩ OPT202 ID +15V –15V 2 R1 1kΩ 1MΩ IO ≤ 5mA IO = ID 1 + C1 0.1µF R1 1MΩ 4 3pF RF R1 175Ω λ FIGURE 6. Current Output Circuit. 5 VO OPT202 8 See AB-061 for details. Other application circuits can be seen in the OPT209 data sheet. 20dB/decade f–3dB = R1 2πR2R3C2 = 16Hz Circuit requires DIP package. FIGURE 8. DC Restoration Rejects Unwanted Steady-State Background Light. ® 9 OPT202