Datasheet OPT101P-J, OPT101P Datasheet (Burr Brown)

®

OPT101

MONOLITHIC PHOTODIODE AND

SINGLE-SUPPLY TRANSIMPEDANCE AMPLIFIER

FEATURES

● SINGLE SUPPLY: +2.7 to +36V

● PHOTODIODE SIZE: 0.090 x 0.090 inch

● INTERNAL 1MΩ FEEDBACK RESISTOR

= 1MΩ

F

(650nm)

µA

● HIGH RESPONSIVITY: 0.45A/W

● BANDWIDTH: 14kHz at R

● LOW QUIESCENT CURRENT: 120

● AVAILABLE IN 8-PIN DIP, 5-PIN SIP, AND

8-LEAD SURFACE MOUNT PACKAGES

APPLICATIONS

● MEDICAL INSTRUMENTATION

● LABORATORY INSTRUMENTATION

● POSITION AND PROXIMITY SENSORS

● PHOTOGRAPHIC ANALYZERS

● BARCODE SCANNERS

● SMOKE DETECTORS

● CURRENCY CHANGERS

(Pin available

on DIP only.)

λ

2 (2)

(1)

7.5mV

V

B

V+

1

3pF

1MΩ

8pF

OPT101

(3)

3

8

(4)

54(5)

DESCRIPTION

The OPT101 is a monolithic photodiode with on-chip
transimpedance amplifier. Output voltage increases
linearly with light intensity. The amplifier is designed
for single or dual power supply operation, making it
ideal for battery operated equipment.

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 0.09 x 0.09
inch photodiode is operated in the photoconductive
mode for excellent linearity and low dark current.

The OPT101 operates from +2.7V to +36V supplies
and quiescent current is only 120µA. It is available in
clear plastic 8-pin DIP, 5-pin SIP and J-formed DIP for
surface mounting. Temperature range is 0°C to 70°C.

0.7

Ultraviolet

0.6

0.5

0.4

0.3

0.2

Voltage Output (V/µW)

0.1

0

200 300 400 500 600 700 800 900 1000 1100

SPECTRAL RESPONSIVITY

Blue

Green

Yellow

Using Internal
1MΩ Resistor

Wavelength (nm)

Red

Infrared

0.7

0.6

0.5

0.4

0.3

0.2

Photodiode Responsivity (A/W)

0.1

0

(SIP)

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Internet: http://www.burr-brown.com/ • FAXLine: [phone] (US/Canada Only) • Cable: BBRCORP • Telex: 066-6491 • FAX: [phone] • Immediate Product Info: [phone]

©

1994 Burr-Brown Corporation PDS-1257D Printed in U.S.A. March, 1998

DIP

®

1

OPT101

SPECIFICATIONS

At TA = +25°C, VS = +2.7V to +36V, λ = 650nm, internal 1MΩ feedback resistor, and RL = 10kΩ, unless otherwise noted.

OPT101P, W
PARAMETER CONDITIONS MIN TYP MAX UNITS
RESPONSIVITY

Photodiode Current 650nm 0.45 A/W
Voltage Output 650nm 0.45 V/µW

vs Temperature 100 ppm/°C
Unit to Unit Variation 650nm ±5%
Nonlinearity
Photodiode Area (0.090 x 0.090in) 0.008 in

DARK ERRORS, RTO

Offset Voltage, Output +5 +7.5 +10 mV

vs Temperature ±2.5 µV/°C

vs Power Supply V
Voltage Noise, Dark, f

TRANSIMPEDANCE GAIN

Resistor 1MΩ
Tolerance, P ± 0.5 ± 2%

FREQUENCY RESPONSE

Bandwidth V
Rise Fall Time, 10% to 90% V
Settling Time, 0.05% V

Overload Recovery 100%, Return to Linear Operation 50 µs

OUTPUT

Voltage Output, High (V
Capacitive Load, Stable Operation 10 nF
Short-Circuit Current V

POWER SUPPLY

Operating Voltage Range +2.7 +36 V
Quiescent Current Dark, V

TEMPERATURE RANGE

Specification 0 +70 °C
Operating 0 +70 °C
Storage –25 +85 °C
Thermal Resistance,

NOTES: (1) Deviation in percent of full scale from best-fit straight line. (2) Referred to Output. Includes all error sources.

(1)

FS Output = 24V ±0.01 % of FS

2

(2.29 x 2.29mm) 5.2 mm

(2)

= +2.7V to +36V 10 100 µV/V

= 0.1Hz to 20kHz VS = +15V, V

B

S

= –15V 300 µVrms

PIN3

W ±0.5 %

vs Temperature ±50 ppm/°C

= 10Vp-p 14 kHz

OUT

= 10V Step 28 µs

OUT

= 10V Step 160 µs

0.1% 80 µs

OUT

1% 70 µs

) – 1.3 (VS) – 1.15 V

S

= 36V 15 mA

S

= 0V 120 240 µA

PIN3

R

= ∞, V

L

θ

JA

= 10V 220 µA

OUT

100 °C/W

2

PHOTODIODE SPECIFICATIONS

TA = +25°C, VS = +2.7V to +36V unless otherwise noted.

Photodiode of OPT101P

PARAMETER CONDITIONS MIN TYP MAX UNITS

Photodiode Area (0.090 x 0.090in) 0.008 in

(2.29 x 2.29mm) 5.2 mm

Current Responsivity 650nm 0.45 A/W

650nm 865 µA/W/cm

Dark Current V

vs Temperature doubles every 7°C

= 7.5mV 2.5 pA

DIODE

Capacitance 1200 pF

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.

®

OPT101

2

2

2

2

OP AMP SPECIFICATIONS

At TA = +25°C, VS = +2.7V to +36V, λ = 650nm, internal 1MΩ feedback resistor, and RL = 10kΩ, unless otherwise noted.

OPT101 Op Amp
PARAMETER CONDITIONS MIN TYP MAX UNITS
INPUT

Offset Voltage ±0.5 mV

vs Temperature ±2.5 µV/°C
vs Power Supply 10 µV/V

Input Bias Current (–) Input 165 pA

vs Temperature (–) Input 1 pA/°C

Input Impedance

Differential 400 || 5 MΩ || pF

Common-Mode 250 || 35 GΩ || pF
Common-Mode Input Voltage Range Linear Operation 0 to [(V
Common-Mode Rejection 90 dB

OPEN-LOOP GAIN

Open-loop Voltage Gain 90 dB

FREQUENCY RESPONSE

Gain-Bandwidth Product

(2)

Slew Rate 1V/µs
Settling Time 1% 5.8 µs

0.1% 7.7 µs

0.05% 8.0 µs

OUTPUT

Voltage Output, High (V
Short-Circuit Current V

= +36V 15 mA

S

– 1.3 (VS) – 1.15 V

S)

POWER SUPPLY

Operating Voltage Range +2.7 +36 V
Quiescent Current Dark, V

R

= 0V 120 240 µA

PIN3

∞, V

= 10V 220 µA

L

OUT

NOTES: (1) Op amp specifications provided for information and comparison only. (2) Stable gains ≥ 10V/V.

(1)

) – 1] V

S

2 MHz

®

3

OPT101

PIN CONFIGURATIONS

Top View DIP

ELECTROSTATIC
DISCHARGE SENSITIVITY

1

V

S

2

–In

–V

1MΩ Feedback

NOTE: (1) Photodiode location.

Top View SIP

Common

V

S

–V

1MΩ Feedback

Output

(1)

3
4

1
2

(1)

3
4
5

8
7
6
5

Common
NC
NC
Output

ABSOLUTE MAXIMUM RATINGS

Supply Voltage (VS to

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)

“Common”

or pin 3) ................................0 to +36V

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
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 OPT101 plastic
packages cannot meet flammability test, UL-94.

PACKAGE INFORMATION

PRODUCT COLOR PACKAGE NUMBER

OPT101P Clear 8-Pin Plastic DIP 006-1
OPT101P-J Clear 8-Lead Surface Mount
OPT101W Clear 5-Pin Plastic SIP 321

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 J-formed
leads for surface mounting.

PACKAGE DRAWING

(2)

(1)

006-4

®

OPT101

4

TYPICAL PERFORMANCE CURVES

VOLTAGE RESPONSIVITY vs RADIANT POWER

Radiant Power (µW)

Output Voltage (V)

0.01 0.1 10 100 1k1

10

1

0.1

0.01

0.001

R

F

= 1MΩ

R

F

= 100kΩ

R

F

= 10MΩ

λ = 650nm

R

F

= 50kΩ

DARK V

OUT

vs TEMPERATURE

Temperature (°C)

0 10203040506070

8

7.8

7.6

7.4

7.2

7

Output Voltage (mV)

VOLTAGE RESPONSIVITY vs FREQUENCY

Frequency (Hz)

100 1k 10k 100k

10

1

0.1

0.01

0.001

Responsivity (V/µW)

R

F

= 50kΩ, C

EXT

= 56pF

R

F

= 10MΩ

R

F

= 1MΩ

R

F

= 100kΩ, C

EXT

= 33pF

At TA = +25°C, VS = +2.7V to +36V, λ = 650nm, internal 1MΩ feedback resistor, and RL = 10kΩ, unless otherwise noted.

1.0

0.9

0.8

0.7

0.6

0.5

NORMALIZED SPECTRAL RESPONSIVITY

Ultraviolet

Blue

Green

Yellow

Red

650nm

(0.45A/W)

Infrared

25°C

0.4

0.3

0.2

0.1

Normalized Current or Voltage Output

0

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

F

R

= 50kΩ

λ = 650nm

0.001

0.001 0.01 1 10 1000.1
Irradiance (W/m

2

)

70°C

1.0

RESPONSE vs INCIDENT ANGLE

0.8

SIP Package

θ

X

θ

Y

0.6

0.4

θ

X

DIP Package

Plastic

θ

Y

Relative Response

0.2

0

0

±20 ±40 ±60 ±80

Incident Angle (°)

1.0

θ

X

θ

Y

0.8

0.6

0.4

0.2

0

®

5

OPT101

TYPICAL PERFORMANCE CURVES (CONT)

At TA = +25°C, VS = +2.7V to +36V, λ = 650nm, internal 1MΩ feedback resistor, and RL = 10kΩ, unless otherwise noted.

300

QUIESCENT CURRENT vs TEMPERATURE

275
250

V

= 15V, V

S

OUT

225
200

V

= 5V, V

175

S

150
125

Quiescent Current (µA)

100

75

V

= +5V, V

S

50

010203040 6050 70

OUT

OUT

– V

– V

PIN3

PIN3

= 5V

V

= 0V

= +15V, V

S

OUT

– V

Temperature (°C)

20

SHORT CIRCUIT CURRENT vs V

18
16
14
12
10

8
6
4

Short Circuit Current (mA)

2
0

0 5 10 15 20 25 30 35 40

VS (V)

– V

PIN3

= 15V

300

250

200

QUIESCENT CURRENT vs (V

V

= 36V

S

OUT

– V

V

V

S

)

PIN3

= 15V

S

= 2.7V

150

= 0V

PIN3

100

Quiescent Current (µA)

50

0

0 5 10 15 20 25 30 35 40

– V

V

OUT

S

180

(I

BIAS-IDARK

(V)

PIN3

) vs TEMPERATURE

160
140
120
100

(pA)

80

DARK

60

-I

40

λ

BIAS

I

20

0
–20
–40

0 10203040506070

I

FEEDBACK

(I

BIAS-IDARK

I

BIAS

I

DARK

(1)

8

V

B

OPT101

3pF

)

1MΩ

8pF

Temperature (°C)

OUTPUT NOISE VOLTAGE vs

MEASUREMENT BANDWIDTH, V

1000

R

= 10MΩ

F

100

10

Noise Voltage (µVrms)

1

0.1
10 100 1k 10k 100k 1M

= +15, V

S

OUT

R

F

R

= 100kΩ || 33pF

F

R

= 50kΩ || 56pF

F

= 1MΩ

Frequency (Hz)

®

OPT101

– V

= 15V

PIN3

INTERNAL

NOISE EFFECTIVE POWER vs

MEASUREMENT BANDWIDTH, V

–7

10

–8

10

–9

10

10

Noise Effective Power (W)

10

10

R

= 50k || 56pF

F

–10

–11

–12

10 100 1k 10k 100k 1M

= +15, V

S

R

= 100k || 33pF

F

R

= 10MΩ

F

R

F

OUT

= 1MΩ

– V

INTERNAL

PIN3

= 0

Bandwidth (Hz)

6

TYPICAL PERFORMANCE CURVES (CONT)

At TA = +25°C, VS = +2.7V to +36V, λ = 650nm, internal 1MΩ feedback resistor, and RL = 10kΩ, unless otherwise noted.

SMALL SIGNAL RESPONSE LARGE SIGNAL RESPONSE

SMALL SIGNAL RESPONSE (C

(Pin 3 = 0V)

= 10,000 pF)

LOAD

SMALL SIGNAL RESPONSE (C

(Pin 3 = –15V)

= 10,000 pF)

LOAD

®

7

OPT101

APPLICATIONS INFORMATION

Figure 1 shows the basic connections required to operate the
OPT101. Applications with high-impedance power supplies
may require decoupling capacitors located close to the
device pins as shown. Output is 7.5mV dc with no light and
increases with increasing illumination.

Photodiode current, I
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.”

λ

FIGURE 1. Basic Circuit Connections.

, is proportional to the radiant power, or

D

= +2.7 to +36V

V

S

(Pin available

2

on DIP only.)

(1)

8

Common

V

B

3

1

1MΩ

(3)

(2)

3pF

8pF

OPT101

0.01 to 0.1µF

4

(4)

5

(5)

Dark output ≈ 7.5mV

Positive going output

with increased light

source to sink currents up to approximately 100µA. The
benefits of this current sink are shown in the typical
performance curves “Small Signal Response (C

LOAD

=
10,000pF)” which compare operation with pin 3 grounded
and connected to –15V.

Due to the architecture of this output stage current sink, there
is a slight increase in operating current when there is a voltage
between pin 3 and the output. Depending on the magnitude of
this voltage, the quiescent current will increase by
approximately 100µA as shown in the typical performance

– V

curve "Quiescent Current vs (V

(Pin available

2

on DIP only.)

λ

(1)

8

Common

V

OUT

B

OPT101

)".

PIN3

V

S

0.01 to 0.1µF

(2)

1

3pF

1MΩ

8pF

(3)

3

–V = –1V to (VS – 36V)

4

(4)

5

(5)

0.01 to 0.1µF

FIGURE 2. Bipolar Power Supply Circuit Connections.

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

2

Irradiance” is based on the photodiode area of 5.2mm

.

The OPT101’s voltage output is the product of the photodiode
current times the feedback resistor, (I
voltage, V

, of approximately 7.5mV introduced for single

B

), plus a pedestal

DRF

supply operation. The internal feedback resistor is laser trimmed
to 1MΩ. Using this resistor, the output voltage responsivity, RV,
is approximately 0.45V/µW at 650nm wavelength. Figure 1
shows the basic circuit connections for the OPT101 operating
with a single power supply and using the internal 1MΩ feedback
resistor for a response of 0.45V/µW at 650nm. Pin 3 is
connected to common in this configuration.

CAPACITIVE LOADING

The OPT101 is capable of driving load capacitances of 10nF
without instability. However, dynamic performance with
capacitive loads can be improved by applying a negative
bias voltage to Pin 3 (shown in Figure 2). This negative
power supply voltage allows the output to go negative in
response to the reactive effect of a capacitive load. An
internal JFET connected between pin 5 (output) and pin 3
allows the output to sink current. This current sink capability
can also be useful when driving the capacitive inputs of
some analog-to-digital converters which require the signal

NOISE PERFORMANCE

Noise performance of the OPT101 is determined by the op
amp characteristics, feedback components and photodiode
capacitance. The typical performance curve “Output Noise
Voltage vs Measurement Bandwidth” shows how the noise
varies with R

and measured bandwidth (0.1Hz to the

F

indicated frequency), when the output voltage minus the
voltage on pin 3 is greater than approximately 50mV. Below
this level, the output stage is powered down, and the effective
bandwidth is decreased. This reduces the noise to
approximately 1/3 the nominal noise value of 300µVrms, or
100µVrms. This enables a low level signal to be resolved.

Noise can be reduced by filtering the output with a cutoff
frequency equal to the signal bandwidth. This will improve
signal-to-noise ratio. Also, output noise increases in proportion
to the square root of the feedback resistance, while responsivity
increases linearly with feedback resistance. Best signal-to-noise
ratio is achieved with large feedback resistance. This comes
with the trade-off of decreased bandwidth.

The noise performance of the photodetector is sometimes
characterized by Noise Effective Power (NEP). This is the
radiant power that 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 “Noise Effective Power” vs
Measurement Bandwidth" illustrates the NEP for the OPT101.

®

OPT101

8

DARK ERRORS

The dark errors in the specification table include all sources.
The dominant source of dark output voltage is the “pedestal”
voltage applied to the non-inverting input of the op amp.
This voltage is introduced to provide linear operation in the
absence of light falling on the photodiode. Photodiode dark
current is approximately 2.5pA and contributes virtually no
offset error at room temperature. The bias current of the op
amp's summing junction (– input) is approximately 165pA.
The dark current will be subtracted from the amplifier's bias
current, and this residual current will flow through the
feedback resistor creating an offset. The effects of temperature
on this difference current can be seen in the typical
performance curve “(I

BIAS

– I

) vs Temperature.” The

DARK

dark output voltage can be trimmed to zero with the optional
circuit shown in Figure 3. A low impedance offset driver (op
amp) should be used to drive pin 8 (DIP) because this node
has signal-dependent currents.

This capacitor eliminates gain peaking and prevents
instability. The value of C
table in Figure 4. Values of R

can be determined from the

EXT

, other than shown in the table,

F

can be interpolated.

V

S

2

λ

V

B

(1)

8

(2)

1

3pF

1MΩ

8pF

OPT101

(3)

3

(4)
R

(5)

4

EXT

5

Pin Numbers:

DIP (SIP)

C

EXT

4

(4)

5

(5)

for VO = 0V

with no light.

R

1

500kΩ

1/2 REF200

100µA

Pin Numbers:

DIP (SIP)

V

Adjust R

V

(Pin available

2

on DIP only.)

λ

Common

V

B

(1)

8

+15V

OPA177

–15V –15V

S

(2)

1

3pF

1MΩ

8pF

OPT101

(3)

3

–V

FIGURE 3. Dark Error (Offset) Adjustment Circuit.

(a)-

Series R

R

(MΩ) (pF) (x10

O

1

C

EXT

150 2 8
225 3 6

5 10 6 2.5
10 5 11 1.3
50 — 51 0.33

EXT

2

λ

8

(for SIP package).

EXT

DC Gain Bandwidth

6

V/A) (kHz)

C

EXT

R

EXT

V

S

(2)

1

3pF

1MΩ

8pF

V

B

OPT101

3

4

5

CHANGING RESPONSIVITY

An external resistor, R

, can be connected to set a different

EXT

voltage responsivity. To increase the responsivity, this resistor
can be placed in series with the internal 1MΩ (Figure 4a), or
with the DIP package, the external resistor can replace the
internal resistor by not connecting pin 4 (Figure 4b). The
second configuration also allows the circuit gain to be
reduced below 106V/A by using external resistors of less
than 1MΩ.

Figure 4 includes tables showing the responsivity and
bandwidth. For values of R
capacitor, C

should be connected in parallel with RF.

EXT

less than 1MΩ, an external

F

(b)-

External Feedback (for DIP package).

R

(MΩ) (pF) (x10

0.05

0.1

Note: (1) May require 1kΩ in series with pin 5 when driving
large capacitances.

C

EXT

1— 1 23

2 — 2 9.4

5 — 5 3.6
10 — 10 1.8
50 — 50 0.34

EXT

(1)

56 0.05 58

(1)

33 0.1 44

DC Gain Bandwidth

6

V/A) (kHz)

FIGURE 4. Changing Responsivity with External Resistor.

9

OPT101

®

LIGHT SOURCE POSITIONING

The OPT101 is tested with a light source that uniformly
illuminates the full area of the integrated circuit, including
the op amp. Although IC amplifiers are light-sensitive to
some degree, the OPT101 op amp circuitry is designed to
minimize this effect. Sensitive junctions are shielded with
metal, and the photodiode area is very large relative to the op
amp input circuitry.

If your light source is focused to a small area, be sure that
it is properly aimed to fall on the photodiode. A narrowly
focused beam falling on only the photodiode will provide
improved settling times compared to a source that uniformly
illuminates the full area of the die. If a narrowly focused
light source were to miss the photodiode area and fall only
on the op amp circuitry, the OPT101 would not perform
properly. The large 0.09" x 0.09" (2.29mm x 2.29mm)
photodiode area allows easy positioning of narrowly focus­ed light sources. The photodiode area is easily visible, as it
appears very dark compared to the surrounding active
circuitry.

The incident angle of the light source also effects 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 package. These effects are
shown in the typical performance curve “Responsivity vs
Incident Angle.”

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

approximately 14kHz. The R and C values are 1MΩ and
11pF respectively. By using external resistors, with less than
3pF parasitic capacitance, the frequency response can be
improved. An external 1MΩ resistor used in the configuration
shown in Figure 4b will create a 23kHz bandwidth with the

6

same 10

V/A dc transimpedance gain. This yields a rise time

of approximately 15µs (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 “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

where:

is the rise time (10% to 90%)

t

r

f

is the –3dB bandwidth

C

LINEARITY PERFORMANCE

The photodiode is operated in the photoconductive mode so
the current output of the photodiode is very linear with
radiant power throughout a wide range. Nonlinearity remains
below approximately 0.05% 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.

21

0.01 to

0.1µF

λ

V

B

83

FIGURE 5. Three-Wire Remote Light Measurement.

®

OPT101

1MΩ

3pF

8pF

OPT101

10

4

5

NOTE: Pin Numbers for DIP Package.

+2.7 to

+36V

V

OUT

2

1MΩ

+15V

1

3pF

4

8pF

λ

λ

NOTE: OPT101 Pin Numbers for DIP Package.

V

B

OPT101

38

2

1MΩ

V

B

+15V

1

3pF

8pF

OPT101

38

FIGURE 6. Differential Light Measurement.

+15V

V

01

5

4

100kΩ

5

V

02

100kΩ

2

3

6

9

7

INA118

4

–15V

LOG100

1nF

5

3

1

R

G

8

+15V

14

1

–15V

Difference Output

6

V

= (V

OUT

Log of Ratio Measurement

(Absorbance)

V

7

OUT

– V01) 1+

02

= K log

50kΩ

R

G

10 (V02/V01

)

+15V

2

REF102

4

10V
6

100kΩ

10kΩ

2

3

FIGURE 7. LED Output Regulation Circuit.

3.3nF

+15V

OPA627

4

–15V

0.03µF11kΩ

7

LED

+15V

2 1

3pF

1MΩ

8pF

270Ω

6

LED

V

IN4148

Glass Microscope Slide

≈ 8%

OPT101

Approximately
92% light
available for application.

NOTE: OPT101 Pin Numbers for DIP Package.

B

OPT101

11

4

5

38

®

OPT101