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FPO
OPT210
MONOLITHIC PHOTODIODE AND AMPLIFIER 300kHz Bandwidth at RF = 1MΩ
FEATURES
q BOOTSTRAP ANODE DRIVE: Extends Bandwidth: 900kHz (RF = 100KΩ) Reduces Noise q LARGE PHOTODIODE: 0.09" x 0.09" q HIGH RESPONSIVITY: 0.45A/W (650nm) q EXCELLENT SPECTRAL RESPONSE q WIDE SUPPLY RANGE: ±2.25 to ±18V q TRANSPARENT DIP, SIP AND SURFACEMOUNT PACKAGES
DESCRIPTION
The OPT210 is a photodetector consisting of a high performance silicon photodiode and precision FETinput transimpedance amplifier integrated on a single monolithic chip. Output is an analog voltage proportional to light intensity. The large 0.09" x 0.09" photodiode is operated at low bias voltage for low dark current and excellent linearity. A novel photodiode anode bootstrap circuit reduces the effects of photodiode capacitance to extend bandwidth and reduces noise. The integrated combination of photodiode and transimpedance amplifier on a single chip eliminates the problems commonly encountered with discrete designs such as leakage current errors, noise pick-up and gain peaking due to stray capacitance. The OPT210 operates from ±2.25 to ±18V supplies and quiescent current is only 2mA. Available in a transparent 8-pin DIP, 8-lead surface-mount and 5-pin SIP, it is specified for 0° to 70°C operation.
SPECTRAL RESPONSIVITY
Blue
Ultraviolet
APPLICATIONS
q BARCODE SCANNERS q MEDICAL INSTRUMENTATION q LABORATORY INSTRUMENTATION q POSITION AND PROXIMITY DETECTORS q PARTICLE DETECTORS
Red
V+ 1 (2) 2 (3)
Green Yellow
RF
0.5
Infrared
0.5 0.4 0.3 0.2 0.1 0 700 800 900 1000 1100
OPT210 5 VO
0.4 0.3 0.2 0.1 0 100
Using External 1MΩ Resistor
λ
+1
(5)
8
(1)
3
(4) V–
DIP Pins
(SIP Pins)
200 300 400 500
600
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
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1 PDS-1313B
OPT210
Photodiode Responsivity (A/W)
Voltage Output (V/µW)
SPECIFICATIONS
At TA = +25°C, VS = ±15V, λ = 650nm, External RF = 1MΩ, RL = 10kΩ, unless otherwise noted. OPT210P OPT210W PARAMETER RESPONSIVITY Photodiode Current Unit-to-Unit Variation Voltage Output Nonlinearity Photodiode Area DARK ERROR, RTO Offset Voltage vs Temperature vs Power Supply Voltage Noise FREQUENCY RESPONSE Bandwidth Rise Time Settling Time, 1% 0.1% 0.01% Overload Recovery OUTPUT Voltage Output, Positive Positive Negative(1) Capacitive Load, Stable Operation Short-Circuit Current(2) POWER SUPPLY Operating Range Quiescent Current TEMPERATURE RANGE Specification Operating Storage θJA CONDITIONS λ = 650nm λ = 650nm, External RF = 1MΩ (0.09 x 0.09in) (2.29 x 2.29mm) MIN TYP 0.45 ±5 0.45 0.01 0.008 5.2 ±2 ±35 100 160 300 1.2 3 8 20 7 (V+)–1.25 –0.4 (V+)–0.75 (V+)–1 –0.5 500 +50 ±18 ±4 70 70 85 100 ±10 1000 MAX UNITS A/W % V/µW % of FS in2 mm2 mV µV/°C µV/V µVrms kHz µs µs µs µs µs V V pF mA V mA °C °C °C °C/W
VS = ±2.25V to ±18V BW = 0.01Hz to 100kHz External RF = 1MΩ 10% to 90% FS to Dark step
100% Overdrive RL = 10kΩ RL = 5kΩ RL = 10kΩ
±2.25 +2.0/–1.7 0 0 –25
NOTES: (1) Output typically swings to 0.5V below the voltage applied to the non-inverting input terminal, which is normally connected to ground. (2) Positive current (sourcing) is limited. Negative current (sinking) is not limited.
PHOTODIODE SPECIFICATIONS
PHOTODIODE PARAMETER Photodiode Area Current Responsivity Dark Current vs Temperature Capacitance Effective Capacitance(1) CONDITIONS (0.09 x 0.09in) (2.29 x 2.29mm) λ = 650nm VD = –1.2V VD = –1.2V VD = –1.2V MIN TYP 0.008 5.2 0.45 865 70 Doubles every 10°C 550 10 MAX UNITS in2 mm2 A/W µA/W/cm2 pA pF pF
NOTES: (1) Effect of photodiode capacitance is reduced by internal buffer bootstrap drive. See text
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.
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OPT210
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OP AMP SPECIFICATIONS
Op amp specifications provided for comparative information only. OP AMP PARAMETER INPUT Offset Voltage vs Temperature vs Power Supply Input Bias Current Inverting Input vs Temperature Non-inverting Input NOISE Voltage Noise f = 10Hz f = 100Hz f = 1kHz Current Noise Density, Inverting Input INPUT VOLTAGE RANGE Common-Mode Input Range(1) Common-Mode Rejection INPUT IMPEDANCE Inverting Input Impedance Non-Inverting Input Impedance OPEN-LOOP GAIN Open-Loop Voltage Gain FREQUENCY RESPONSE Bandwidth, Small Signal Rise Time, Large Signal Settling Time, 1% 0.1% 0.01% Overload Recovery OUTPUT Voltage Output, Positive Positive Negative(1) Capacitive Load, Stable Operation Short-Circuit Current(2) POWER SUPPLY Operating Voltage Quiescent Current VO = 0V to +13.75V CONDITIONS MIN TYP ±2 ±35 100 15 Doubles every 10°C 300 MAX UNITS mV µV/°C µV/V pA µA
BW = 0.01Hz to 100kHz
20 9 6 0.8 VS±2.25 65 3x1010||3 250 70 35 25 240 390 800 7 (V+)–1.25 –0.4 (V+)–0.75 (V+)–1 –0.5 500 +50 ±18 ±4
nV/√Hz nV/√Hz nV/√Hz fA/√Hz V dB Ω || pF kΩ dB MHz ns ns ns ns µs V V pF mA V mA
10% to 90% 10V step
100% Overdrive RL = 10kΩ RL = 5kΩ RL = 10kΩ
±2.25 +1.7/–1.4
NOTES: (1) Output typically swings to 0.5V below the voltage applied to the non-inverting input terminal, which is normally connected to ground. (2) Positive current (sourcing) is limited. Negative current (sinking) is not limited.
BUFFER SPECIFICATIONS
Buffer specifications provided for comparative information only. BUFFER PARAMETER INPUT Offset Voltage(1) Input Bias Current vs Temperature Input Impedance FREQUENCY RESPONSE Bandwidth, Small Signal OUTPUT Current Voltage Gain POWER SUPPLY Operating Range Quiescent Current NOTE: (1) Intentional voltage offset to reverse bias photodiode. ±2.25 CONDITIONS MIN TYP –1.2 15 Doubles every 10°C 1011||3 500 ±200 0.99 ±18 MAX UNITS V pA Ω || pF MHz µA V/V V mA
±0.3
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OPT210
PIN CONFIGURATIONS
Top View
V+ –In V– NC 1 2 3 4 (1) 8 7 6 5 Common NC NC Output
DIP
ELECTROSTATIC DISCHARGE SENSITIVITY
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.
NOTE: (1) Photodiode location.
Top View
Common V+ –In V– Output 1 2 3 4 5 (1)
SIP
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. The fire-retardant fillers used in black plastic are not compatible with clear molding compound. The OPT210 plastic packages cannot meet flammability test, UL-94.
NOTE: (1) Photodiode location.
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 Storage Temperature: P, W ........................................... –25° C to +85°C Junction Temperature: P, W .......................................................... +85°C Lead Temperature (soldering, 10s) ................................................ +300°C (Vapor-Phase Soldering Not Recommended on Plastic Packages)
PACKAGE INFORMATION
PRODUCT OPT210P OPT210P-J OPT210W PACKAGE 8-Pin Plastic DIP 8-Lead Surface Mount(2) 5-Pin Plastic SIP PACKAGE DRAWING NUMBER(1) 006-5 006-6 321-1
NOTE: (1) For detailed drawing and dimension table, please see end of data sheet, or Appendix C of Burr-Brown IC Data Book. (2) 8-pin DIP with leads formed for surface mounting.
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OPT210
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TYPICAL PERFORMANCE CURVES
At TA = +25°C, VS = ±15V, λ = 650nm, unless otherwise noted.
NORMALIZED SPECTRAL RESPONSIVITY 1.0
VOLTAGE RESPONSIVITY vs RADIANT POWER 10
Normalized Current or Voltage Output
0.8
(0.48A/W)
Output Voltage (V)
650nm (0.45A/W)
1
0.6
RF
0.1
=
10
Ω M
1M Ω 10 0k Ω 10 kΩ = 1k Ω
λ = 650nm
RF
=
0.4
RF
0.01
=
0.2
RF
=
RF
0 100 200 300 400 500 600 700 800 900 1000 1100 Wavelength (nm)
0.001 0.01 0.1 1 10 100 1k Radiant Power (µW)
VOLTAGE RESPONSIVITY vs IRRADIANCE 10
100
VOLTAGE OUTPUT RESPONSIVITY vs FREQUENCY RF = 100MΩ
RF
0.1
=
M 10
RF
=
1M
Ω 0 10 kΩ 10 kΩ = Ω 1k
Responsivity (V/µW)
Output Voltage (V)
1
Ω
10
RF = 10MΩ
1
RF = 1MΩ, CF = 0.5pF
RF
=
0.01
RF
=
0.1
RF = 100kΩ, CF = 1.8pF
RF
λ = 650nm
0.01 1k 10k 100k Frequency (Hz) 1M 10M
0.001 0.001 0.01 0.1 1 10 100 Irradiance (W/m2)
RESPONSE vs INCIDENT ANGLE 1.0 θX θY θY 0.8 1.0
Power Supply Rejection (dB)
90 80 70 60 50 40 30 20 10 0
POWER SUPPLY REJECTION vs FREQUENCY
0.8 Relative Response
θX
SIP Package
0.6 θX
Plastic DIP Package
0.6 θY
V–
0.4
0.4
0.2
0.2
V+
0 0 ±20 ±40 Incident Angle (°) ±60
0 ±80
–10 1 10 100 1k 10k 100k 1M 10M Frequency (Hz)
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OPT210
TYPICAL PERFORMANCE CURVES
At TA = +25°C, VS = ±15V, λ = 650nm, unless otherwise noted.
(CONT)
QUIESCENT CURRENT vs TEMPERATURE 3
OUTPUT NOISE VOLTAGE vs MEASUREMENT BANDWIDTH 10–2
Dashed lines indicate noise measured beyond the signal bandwidth.
Quiescent Current (mA)
Noise Voltage (Vrms)
+ IQ
10–3
RF = 10MΩ RF = 100MΩ
2
– IQ + IQ
VS = ±15V
10–4
10–5 RF = 100kΩ 10–6 RF = 1MΩ RF = 10kΩ
1
– IQ
VS = ±2.25V
0 –75 –50 –25 0 25 50 75 100 125 Temperature (°C)
10–7 10 100 1k 10k 100k 1M 10M Frequency (Hz)
SMALL-SIGNAL RESPONSE, RF = 1MΩ Measurement BW = 1MHz
LARGE-SIGNAL RESPONSE, RF = 1MΩ
20mV/div
5µs/div
2V/div
5µs/div
NOISE EFFECTIVE POWER vs MEASUREMENT BANDWIDTH 10–7 Dashed lines indicate noise measured beyond the signal bandwidth. λ = 650nm
RF = 10kΩ RF = 100kΩ RF = 1MΩ RF = 10MΩ RF = 100MΩ
10–8 Noise Effective Power (W)
10–9
10–10
10–11
10–12
10–13
10–14 10 100 1k 10k 100k 1M 10M Frequency (Hz)
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OPT210
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APPLICATIONS INFORMATION
Basic operation of the OPT210 is shown in Figure 1. Power supply bypass capacitors should be connected near the device pins as shown. Noise performance of the OPT210 can be degraded by the high frequency noise on the power supplies. Resistors in series with the power supply pins as shown can be used (optional) to help filter power supply noise An external feedback resistor, RF, is connected from –In to the VO terminal as shown in Figure 1. Feedback resistors of 1MΩ or less require parallel capacitor, CF. See the table of values in Figure 1.
(paracitic capacitance)
The typical performance curve “Output Voltage vs Radiant Power” shows the response throughout a wide range of radiant power and feedback resistor values. The response curve “Output Voltage vs Irradiance” is based on the photodiode area of 5.23x10–6m2. BOOTSTRAP BUFFER The photodiode’s anode is driven by an internal high speed voltage buffer shown in Figure 1. This variation on the classical transimpedance amplifier circuit reduces the effects of photodiode capacitance. The effective photodiode capacitance is reduced from approximately 550pF to 10pF with this bootstrap drive technique. This improves bandwidth and reduces noise. The output voltage of the buffer is offset approximately 1.2V below the input. This reverse biases the photodiode for reduced capacitance. OP AMP A special op amp design is used to achieve wide bandwidth. The op amp output voltage cannot swing lower than 0.5V below the non-inverting input voltage. Since photodiode current always produces a positive output voltage, this does not limit the required output swing. The inverting input is designed for very low input bias current—approximately 15pA. The non-inverting input has much larger bias current—approximately 300µA flows out of this terminal.
+15V
+15V CF 1µF + 100Ω 1 (2) 2 (3) RF OPT210 5 VO (0V to 14V) For RF > 2MΩ, use series-connected resistors. See text.
λ
+1
(5)
8 (1)
3 100Ω
(4) + 1µF
Optional series resistors filter power supply noise. See text.
RF 10MΩ 1MΩ 100kΩ 10kΩ 1kΩ CF (min) (1) 0.5pF 1.8pF 10pF 20pF
–15V
BANDWIDTH 70kHz 300kHz 900kHz 1.6MHz 1.6MHz
0.1µF 1 (2) 2 (3)
RF 1MΩ OPT210 5 VO
NOTE: (1) Two series-connected resistors of RF /2 for low capacitance. See text.
λ
+15V 100µA 1/2 REF200
+1
(5)
Output voltage offset by VA 8 (1) 3 (4) 0.1µF
FIGURE 1. Basic Operation. Bandwidth varies with feedback resistor value. To achieve widest bandwidth with resistors greater than 1MΩ, use care to minimize parasitic parallel capacitance. For widest bandwidth with resistors greater than 2MΩ, connect two resistors (RF/2) in series. Airwiring this interconnection provides lowest capacitance. Although the OPT210 is usable with feedback resistors of 100MΩ and higher, with RF ≥ 10MΩ the model OPT211 will provide lower dc errors and reduced noise. The OPT210’s output voltage is the product of the photodiode current times the external feedback resistor, RF. 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.”
300µA
–15V 200Ω 200Ω 100µA 1/2 REF200 10kΩ OPA131 VA ±20mV
–15V
FIGURE 2. Adjustable Output Offset. An offset voltage can be connected to the non-inverting input as shown in Figure 2. A voltage applied to the noninverting input is summed at the output. Because the noninverting input bias current is high (approximately 300µA), it should be driven by a low impedance such as the bufferconnected op amp shown.
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OPT210
The OPT210 can be connected to operate from a single power supply as shown in Figure 3. The non-inverting input bias current flows through a zener diode to provide a bias voltage. The output voltage is referenced to this bias point.
+15V 0.1µF 1 (2) 2 (3) OPT210 5 RF VO measured relative to 5.6V zener voltage. (5) VO
cosine of the incident 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.” LINEARITY PERFORMANCE Photodiode current is very linear with radiant power throughout its range. Nonlinearity remains below approximately 0.01% up to 200µA. The anode buffer drive, however, is limited to approximately 200µA. This produces an abrupt limit to photodiode output current when radiant power reaches approximately 450µW. Best linearity is achieved with the photodiode uniformly illuminated. A light source focused to a very small beam, illuminating only a small percentage of the photodiode area, may produce a higher nonlinearity. NOISE PERFORMANCE Noise performance of the OPT210 is determined by the op amp characteristics in conjunction with the feedback components, photodiode capacitance, and buffer performance. The typical performance curve “Output Noise Voltage vs Measurement Bandwidth” shows how the noise varies with RF and measured bandwidth (0.1Hz to the indicated frequency). The signal bandwidth of the OPT210 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), or Watts/√Hz to convey spectral information about the noise. The typical performance curve “Output Noise Voltage vs Measurement Bandwidth” is also scaled for NEP on the right-hand side.
λ
+1
(5.6V) 8 ≈300µA ZD1 ZD1: IN4626 5.6V specified at IZ = 250µA (1) + 1µF 3 (4)
FIGURE 3. Single Power Supply Operation. DARK ERRORS The dark errors in the specification table include all sources with RF = 1MΩ. The dominant error source is the input offset voltage of the op amp. Photodiode dark current is approximately 70pA and the combined input bias current of the op amp and buffer is approximately 30pA. Photodiode dark current and input bias current total approximately 100pA at 25°C and double for each 10°C above 25°C. At 70°C, the total error current is approximately 2nA. With RF = 1MΩ, this would produce a 2mV offset voltage in addition to the initial amplifier offset voltage (10mV max) at 25°C. The dark output voltage can be trimmed to zero with the optional circuit shown in Figure 2. LIGHT SOURCE POSITIONING The OPT210 is tested with a light source that uniformly illuminates the full integrated circuit area, including the op amp. Although all IC amplifiers are light sensitive to some degree, the OPT210 op amp circuitry is designed to minimize this effect. Sensitive junctions are shielded with metal where possible. Furthermore, the photodiode area is very large compared to the op amp circuitry making these effects negligible. 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 and fall on the op amp circuitry, the OPT210 would not perform properly. The large photodiode area is clearly visible as a very dark area slightly offset from the center of the IC. The incident angle of the light source also affects the apparent sensitivity in uniform irradiance. For small incident angles, the loss in sensitivity is due to the smaller effective light gathering area of the photodiode (proportional to the
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OPT210
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