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.
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 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.
λ
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
Gain-Bandwidth Product16MHz
Slew Rate6V/µs
Settling Time 0.1%4µs
0.01%5µs
OUTPUT
Voltage OutputR
Short-Circuit Current±18mA
POWER SUPPLY
Specified Operating Voltage±15V
Operating Voltage Range±2.25±18V
Quiescent CurrentI
NOTE: (1) Op amp specifications provided for information and comparison only.
= ±2.25V to ±18V10µV/V
S
12
||3Ω || pF
12
||3Ω || pF
= 10kΩ(V+) – 1.25(V+) – 1V
L
R
= 5kΩ(V+) – 2(V+) – 1.5V
L
= 0±400±500µA
O
(1)
PHOTODIODE SPECIFICATIONS
At TA = +25°C, unless otherwise noted.
Photodiode of OPT202
PARAMETERCONDITIONSMINTYPMAXUNITS
Photodiode Area(0.090 x 0.090in)0.008in
Current Responsivity650nm0.45A/W
Dark CurrentV
vs Temperaturedoubles every 10°C
CapacitanceV
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.
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)
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.
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
S
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 OPT202 plastic
packages cannot meet flammability test, UL-94.
NOTE: (1) For detailed drawing and dimension table, please see end of data
sheet, or Appendix C of Burr-Brown IC Data Book.
(1)
®
OPT202
4
Page 5
TYPICAL PERFORMANCE CURVES
At TA = +25°C, VS = ±15V, λ = 650nm, unless otherwise noted.
1.0
NORMALIZED SPECTRAL RESPONSIVITY
0.8
650nm
(0.45A/W)
0.6
0.4
0.2
Normalized Current or Voltage Output
0
100 200 300 400 500 600 700 800 900 1000 1100
Wavelength (nm)
VOLTAGE RESPONSIVITY vs IRRADIANCE
10
1
= 10MΩ
F
0.1
Output Voltage (V)
0.01
R
= 1MΩ
F
R
= 100kΩ
F
R
λ = 650nm
(0.48A/W)
VOLTAGE RESPONSIVITY vs RADIANT POWER
10
1
F
R
0.1
Output Voltage (V)
0.01
0.001
0.010.1101001k1
VOLTAGE OUTPUT RESPONSIVITY vs FREQUENCY
10
1
0.1
RF = 330kΩ C
Responsivity (V/µW)
0.01
= 10MΩ
R
= 1MΩ
F
= 100kΩ
F
R
Radiant Power (µW)
RF = 10MΩ
R
= 3.3MΩ
F
= 3pF
EXT
λ = 650nm
λ = 650nm
RF = 1MΩ
0.001
0.0010.011101000.1
1.0
0.8
SIP Package
θ
X
0.6
0.4
θ
X
DIP Package
Relative Response
0.2
0
0
Irradiance (W/m
2
)
RESPONSE vs INCIDENT ANGLE
θ
X
θ
Y
Plastic
θ
Y
θ
Y
±20±40±60±80
Incident Angle (°)
1.0
0.8
0.6
0.4
0.2
0
0.001
1.00
0.90
0.80
0.70
0.60
0.50
0.40
Relative Output
0.30
02.0
0.10
5
100
1k10k100k10M
1M
Frequency (Hz)
RESPONSE vs INCIDENT ANGLE
θX and θ
Y
Ceramic
θ
θ
X
DIP Package
θ
Y
0
0 102030405060708090
Angle of Incidence
OPT202
®
Page 6
TYPICAL PERFORMANCE CURVES (CONT)
At TA = +25°C, VS = ±15V, λ = 650nm, unless otherwise noted.
0.6
QUIESCENT CURRENT vs TEMPERATURE
0.5
0.4
0.3
0.2
Quiescent Current (mA)
0.1
0
–50–250255075100125
–75
20mV/div
VS = ±15V
VS = ±2.25V
Temperature (°C)
SMALL-SIGNAL RESPONSE
Dice
–2
10
Dotted lines indicate
noise measured beyond
–3
10
the signal bandwidth.
–4
10
RF = 100MΩ
–5
10
Noise Voltage (Vrms)
–6
10
–7
10
1101k10k100k100
LARGE-SIGNAL RESPONSE
2V/div
OUTPUT NOISE VOLTAGE
vs MEASUREMENT BANDWIDTH
RF = 10MΩ
RF = 100kΩ
RF = 1MΩ
1M
Frequency (Hz)
NOISE EFFECTIVE POWER
–7
10
noise measured beyond
–8
10
vs MEASUREMENT BANDWIDTH
Dotted lines indicate
the signal bandwidth.
λ = 650nm
–9
10
–10
10
–11
10
–12
Noise Effective Power (W)
10
–13
10
–14
10
1101k10k100k100
®
OPT202
10µs/div
Frequency (Hz)
1M
= 100kΩ
R
F
R
= 1MΩ
F
R
= 10MΩ
F
R
= 100MΩ
F
10µs/div
DISTRIBUTION OF RESPONSIVITY
60
50
λ = 650nm
40
30
Units (%)
20
Distribution Totals
100%
Laboratory Test
Data
10
0
0.43
0.440.450.460.470.48
Responsivity (A/W)
6
Page 7
APPLICATIONS INFORMATION
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.
(Pin available on DIP only)
1MΩ
R
F
I
ID is proportional
to light intensity
(radiant power).
I
D
(0V)
3pF
λ
0.1µF0.1µF
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
The OPT202’s voltage output is the product of the photodiode
current times the feedback resistor, (I
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 connected to set a different
voltage responsivity. Best dynamic performance is achieved
by connecting R
< 1MΩ), with the internal resistor as shown in
(for R
F
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 R
less than 1MΩ, an external capacitor, C
F
connected in parallel with R
eliminates gain peaking and prevents instability. The value
of C
can be read from the table in Figure 2.
EXT
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
in series (for RF > 1MΩ), or in parallel
EXT
(see Figure 2). This capacitor
F
D
175Ω
OPT202
–15V+15V
DRF
V
O
VO = ID R
F
–6m2
). The internal
, should be
EXT
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.
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.
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.”
For R
> 1MΩ
F
1MΩ
175Ω
λ
OPT202
EXT
|| 1MΩ
1MΩ
V–
C
EXT
R
EXT
4
175Ω
5
.
V+
For R
< 1MΩ
F
RF = R
2
3pF
λ
OPT202
1
83
V+
EQUIVALENT R
100MΩ
10MΩ
1MΩ
330kΩ2pF
≤100kΩ
NOTES: (1) No C
Not recommended due to possible
op amp instability.
FIGURE 2. Using External Feedback Resistor.
7
V–
C
F
(1)
(1)
(1)
(2)
required. (2)
EXT
OPT202
EXT
RF = R
Circuit Requires
+ 1MΩ
EXT
R
EXT
VO = ID R
F
V
= ID R
O
F
DIP Package
®
Page 8
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 R
= 10MΩ. The OPT202 is useful with
F
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.
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.
1MΩ
3pF
100µA
1/2 REF200
100Ω
100Ω
100µA
1/2 REF200
V+
V–
λ
500Ω
0.01µF
Adjust dark output for 0V.
Trim Range: ±7mV
V+
175Ω
V
OPT202
V–
FIGURE 3. Dark Error (Offset) Adjustment Circuit.
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—
0. 35
tR≈
f
C
(1)
where:
t
is the rise time (10% to 90%)
R
f
is the –3dB bandwidth
C
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 R
and measured
F
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.
O
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
and measurement bandwidth.
with R
F
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.
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.
DYNAMIC RESPONSE
Using the internal 1MΩ resistor, the dynamic response of
the photodiode/op amp combination can be modeled as a
®
OPT202
1MΩ
R
F
3pF
175Ω
Gain Adjustment
λ
OPT202
V+
FIGURE 4. Responsivity (Gain) Adjustment Circuit.
8
V–
+50%; –0%
5kΩ
10kΩ
V
O
Page 9
1MΩ
1MΩ
OPT202
3pF
175Ω
VO = IDR
F
V
Z
λ
V+
R
F
0.1µF
(pesudo-ground)
–
+
V
Z
(1)
3.3V
NOTE: (1) Zener diode or other shunt regulator.
5kΩ
1MΩ
OPT202
3pF
175Ω
2
8
5
4
V
O
λ
See AB-061 for details.
Circuit requires DIP package.
C
1
0.1µF
R
2
1MΩ
R
3
100kΩ
R
1
1MΩ
C
2
0.1µF
A
1
R
1
2πR2R3C
2
f
–3dB
=
20dB/decade
= 16Hz
R
F
3pF
175Ω
λ
OPT202
V+
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
V–
.
F
FIGURE 5. “T” Feedback Network.
1MΩ
R
3pF
175Ω
λ
OPT202
I
D
+15V
–15V
F
R1 + R
V
= ID R
O
R
R
1
19kΩ
R
2
1kΩ
R
1
1kΩ
2
F
2
FIGURE 7. Single Power Supply Operation.
IO ≤ 5mA
R
IO = ID 1 +
F
R
1
FIGURE 6. Current Output Circuit.
Other application circuits can be seen in the
OPT209 data sheet.
FIGURE 8. DC Restoration Rejects Unwanted Steady-State
Background Light.
9
OPT202
®
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