®
OPT301
FPO 70%
INTEGRATED PHOTODIODE AND AMPLIFIER FEATURES
DESCRIPTION
● PHOTODIODE SIZE: 0.090 x 0.090 inch (2.29 x 2.29mm)
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 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.
● ● ● ● ● ● ●
1MΩ FEEDBACK RESISTOR HIGH RESPONSIVITY: 0.47A/W (650nm) IMPROVED UV RESPONSE LOW DARK ERRORS: 2mV BANDWIDTH: 4kHz 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.
● HERMETIC TO-99
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.
APPLICATIONS ● ● ● ● ●
MEDICAL INSTRUMENTATION LABORATORY INSTRUMENTATION POSITION AND PROXIMITY SENSORS PHOTOGRAPHIC ANALYZERS SMOKE DETECTORS
40pF
75Ω
λ
5
VO
Infrared
0.5
Using Internal 1MΩ Resistor
0.4
0.4
0.3
0.3
0.2
0.2
0.1
0.1
OPT301 8
1 V+
0
3
100
V–
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 • Cable: BBRCORP • Telex: 066-6491 • FAX: (520) 889-1510 • Immediate Product Info: (800) 548-6132
©
1994 Burr-Brown Corporation
PDS-1228
Printed in U.S.A. January, 1994
Photodiode Responsivity (A/W)
4
Voltage Output (V/µW)
1MΩ
Red
Blue
Ultraviolet
0.5
2
Green Yellow
SPECTRAL RESPONSIVITY
SPECIFICATIONS ELECTRICAL TA = +25°C, VS = ±15V, λ = 650nm, internal 1MΩ feedback resistor, unless otherwise noted. OPT301M PARAMETER
CONDITIONS
RESPONSIVITY Photodiode Current Voltage Output vs Temperature Unit-to-Unit Variation Nonlinearity(1) Photodiode Area DARK ERRORS, RTO(2) Offset Voltage, Output vs Temperature vs Power Supply Voltage Noise
MIN
650nm 650nm 650nm FS Output = 10V (0.090 x 0.090in) (2.29 x 2.29mm)
0.47 0.47 200 ±5 0.01 0.008 5.2
VS = ±2.25V to ±18V Measured BW = 0.1 to 100kHz
±0.5 ±10 10 160
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
OUTPUT Voltage Output
1 ±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 IO = 0
TEMPERATURE RANGE Specification Operating/Storage Thermal Resistance, θJA
MAX
UNITS A/W V/µW ppm/°C % % of FS in2 mm2
±2 100
±2
mV µV/°C µV/V µVrms MΩ % ppm/°C
4 90 240 350 900 240 500 1000
kHz µs µs µs µs µs µs µs
(V+) – 0.65 (V+) – 1 10 ±18
V V nF mA
±15 ±0.4
–40 –55
±18 ±0.5
V V mA
+85 +125
°C °C °C/W
MAX
UNITS
200
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 OPT301 PARAMETER
CONDITIONS
Photodiode Area Current Responsivity Dark Current vs Temperature Capacitance
MIN
(0.090 x 0.090in) (2.29 x 2.29mm) 650nm VD = 0V(1) VD = 0V(1)
NOTE: (1) Voltage Across Photodiode.
®
OPT301
TYP 0.008 5.1 0.47 500 doubles every 10°C 4000
2
in2 mm2 A/W fA pF
SPECIFICATIONS
(CONT) Op Amp Section of OPT301(1)
ELECTRICAL TA = +25°C, VS = ±15V, unless otherwise noted.
OPT301 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%
380 0.5 4 5
kHz V/µs µs µs
(V+) – 0.65 (V+) – 1 ±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 ±0.4
±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
OPT301
DICE INFORMATION
Photodiode Area 0.090 x 0.090 inch 2.29 x 2.29 mm
PAD
FUNCTION
1 2 3 4 5 6 7 8A, 8B
V+ –In V– 1MΩ Feedback Output NC NC Common
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 Die Size Die Thickness Min. Pad Size
MILS (0.001")
MILLIMETERS
154 x 120 ±5 20 ±3 4x4
3.91 x 3.05 ±0.13 0.51 ±0.08 0.1 x 0.1
Backing
None
OPT301 DIE TOPOGRAPHY
PIN CONFIGURATION
ELECTROSTATIC DISCHARGE SENSITIVITY
Top View Common
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.
8 V+ 1
7
–In 2
NC Photodiode Area 6 NC
3
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.
5
V– 4 1MΩ Feedback
Output
PACKAGE INFORMATION
NOTE: Metal package is internally connected to common (Pin 8).
MODEL
PACKAGE
PACKAGE DRAWING 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 D of Burr-Brown IC Data Book.
ABSOLUTE MAXIMUM RATINGS 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
®
OPT301
4
TYPICAL PERFORMANCE CURVES At TA = +25°C, VS = ±15V, λ = 650nm, unless otherwise noted.
NORMALIZED SPECTRAL RESPONSIVITY
VOLTAGE RESPONSIVITY vs RADIANT POWER 10
(0.52A/W)
0.8
650nm (0.47A/W)
Output Voltage (V)
Normalized Current or Voltage Output
1.0
0.6
0.4
Ω M
1
RF 0.1
=
10
Ω
RF
=
1M
Ω 0k
RF
=
10
kΩ
0.01
RF
0.2
=
λ = 650nm
10
0.001
0 100
200 300 400 500
600
700 800 900 1000 1100
0.01
0.1
1
10
100
VOLTAGE OUTPUT RESPONSIVITY vs FREQUENCY
VOLTAGE RESPONSIVITY vs IRRADIANCE 10
10
RF = 10MΩ
λ = 650nm
RF = 3.3MΩ
1
M
RF
=
10
Ω
0.1
RF
=
1M
Ω kΩ
RF
0.01
Responsivity (V/µW)
Output Voltage (V)
1k
Radiant Power (µW)
Wavelength (nm)
=
0 10
kΩ
RF
=
10
λ = 650nm
1
RF = 1MΩ RF = 330kΩ CEXT = 30pF RF = 100kΩ CEXT = 90pF
0.1
0.01
RF = 33kΩ CEXT = 180pF RF = 10kΩ CEXT = 350pF
0.001 0.001
0.001
0.01
0.1
1
10
100
100
1k
Irradiance (W/m2)
1M
1.0
1.0 θ
50 40
Relative Response
λ = 650nm Units (%)
100k
RESPONSE vs INCIDENT ANGLE
DISTRIBUTION OF RESPONSIVITY 60
Distribution Totals 100%
30
Laboratory Test Data
20 10 0 0.45
10k Frequency (Hz)
0.8
0.8
0.6
0.6
0.4
0.4
0.2
0.2
0
0.46
0.47
0.48
0.49
0
0.5
±20
±40
±60
0 ±80
Incident Angle (°)
Responsivity (A/W)
®
5
OPT301
TYPICAL PERFORMANCE CURVES At TA = +25°C, VS = ±15V, λ = 650nm, unless otherwise noted.
OUTPUT NOISE VOLTAGE vs MEASUREMENT BANDWIDTH
QUIESCENT CURRENT vs TEMPERATURE
1000
0.6
Noise Voltage (µVrms)
VS = ±15V
0.4 0.3 VS = ±2.25V
Dice
0.2
Dotted lines show noise beyond the signal bandwidth.
100
Ω
MΩ
10 RF
=
0 10
RF
Ω 0M
RF
=1
=
1M
1
0.1
RF = 10kΩ CEXT = 350pF RF = 100kΩ CEXT = 90pF
0.1
0 –75
–50
–25
0
25
50
75
100
1
125
10
100
1k
LARGE-SIGNAL DYNAMIC RESPONSE
SMALL-SIGNAL DYNAMIC RESPONSE
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
Noise Effective Power (W)
10–8
RF = 10k RF = 100k
10–9 RF = 1M 10–10 RF = 10M 10–11 RF = 100M 10–12
10–13
10–14 1
10
100
1k
Measurement Bandwidth (Hz)
®
OPT301
10k
Measurement Bandwidth (Hz)
Temperature (°C)
20mV/div
Quiescent Current (mA)
0.5
6
10k
100k
100k
APPLICATIONS INFORMATION
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.
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.
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.”
2 1MΩ
ID is proportional to light intensity (radiant power).
λ
(0V)
RF
4
ID
40pF
75Ω
ID
5
VO VO = ID R F
OPT301 8
NOTE: Metal package is internally connected to common (Pin 8).
1
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.
3
0.1µF 0.1µF +15V
–15V
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.”
CEXT
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.
RF 2
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.
1MΩ
4
40pF
75Ω
λ
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.
5 VO = ID RF
OPT301 8
1 V+
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.
3 V–
EXTERNAL RF
CEXT
100MΩ 10MΩ 1MΩ 330kΩ 100kΩ 33kΩ 10kΩ
(1) (1) (1)
30pF 130pF 180pF 350pF
NOTE: (1) No CEXT required.
FIGURE 2. Using External Feedback Resistor.
®
7
OPT301
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.
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.
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.
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.
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.
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
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.
C
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 1MΩ
2 1MΩ
4
RF
4
40pF Gain Adjustment +50%; –0%
40pF
75Ω V+
75Ω
λ
100µA 1/2 REF200
5
λ
VO
OPT301 8
OPT301 8
1 V+
100Ω
1 V+
3
3 V–
5
VO
5kΩ 10kΩ
V–
500Ω
100Ω
FIGURE 4. Responsivity (Gain) Adjustment Circuit.
0.01µF
100µA 1/2 REF200
Adjust dark output for 0V. Trim Range: ±7mV V–
FIGURE 3. Dark Error (Offset) Adjustment Circuit.
®
OPT301
8
This OPT301 used as photodiode, only.
2
2
1MΩ
RF
1MΩ
4
40pF VO = 75Ω
ID RF
75Ω
R2 1kΩ
V–
NC
OPT301
3
V+
NC
5
λ
R1 19kΩ
OPT301 1
R2
4
40pF
5
λ 8
R1 + R2
RF
1
8
ID1
3
2 1MΩ
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.
RF
4
40pF
FIGURE 5. “T” Feedback Network.
75Ω
5
λ OPT301 2 1MΩ
RF1
ID2
4
1
8
λ
VO = (ID2 – ID1) RF
3
V+
Bandwidth is reduced to 2.8kHz due to additional photodiode capacitance.
V–
40pF
75Ω
VO
FIGURE 7. Differential Light Measurement. 5 VO = ID1 RF1 + ID2 RF2
OPT301 8
1 V+
2
3
1MΩ
V–
Max linear input voltage (V+) –0.6V typ
RF
40pF
2
75Ω
1MΩ
RF2
λ
4
ID
75Ω
λ
5
V+
8
1 +15V
3 –15V
VO = ID2 RF2
R1 1kΩ
IO ≤ 5mA
OPT301 1
5
OPT301
40pF
8
4
IO = ID 1 +
3
RF R1
V–
FIGURE 8. Current Output Circuit.
FIGURE 6. Summing Output of Two OPT301s.
®
9
OPT301
2 1MΩ
RF
2
4
1MΩ
40pF
λ
Output filter reduces output noise from 250µV to 195µV.
5
75Ω
λ
+ OPT301 1
VO = IDRF
VZ(1)
VO
10nF
8
1
VZ 5kΩ
5
OPT301
3 –
3.3V
4
40pF
75Ω
8
RF1
3
V+
V–
(pesudo-ground)
FIGURE 10. Output Filter to Reduce Noise.
0.1µF
V+
NOTE: (1) Zener diode or other shunt regulator.
FIGURE 9. Single Power Supply Operation.
2 1MΩ
RF1
INA106
4 10kΩ
40pF
100kΩ
5
2
75Ω
λ
5
Difference Measurement VO = 10 (VO2 – VO1)
6
VO1 = ID1 RF1 3
10kΩ
100kΩ
1
OPT301 8
1 V+
3 V–
G = 10
2 1MΩ
RF2
100kΩ 4 100kΩ
40pF
1 14
LOG100
3 75Ω
λ
5
VO2 = ID2 RF2
CC
OPT301 8
1 V+
3 V–
FIGURE 11. Differential Light Measurement.
®
OPT301
10
1nF
7 10
Log of Ratio Measurement (Absorbance) V VO = K log O1 VO2
C2 0.1µF
R2 1MΩ
R3 100kΩ A1
R1 1MΩ
2 1MΩ
C1 0.1µF
4
40pF
20dB/decade f–3dB = 75Ω
λ
5
1MΩ R3(2πR2C2)
VO
OPT301 8
FIGURE 12. DC Restoration Rejects Unwanted Steady-State Background Light.
1/2 REF200 100µA
100µA 1/2 REF200
1
2 1MΩ
4 10V to 36V
40pF 2N2222 75Ω
λ OPT301 8
20kΩ
5
3
4-20mA (4mA Dark) IN4148
R2 65Ω
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 =
R2 =
1.014 X 106
– 994,000Ω
(1 – 2500 ID max) 26,000
– 26,000Ω
(1 – 2500 ID max)
FIGURE 13. 4-20mA Current-Loop Transmitter.
®
11
OPT301
