Datasheets opt211 Datasheet

®

OPT211

MONOLITHIC PHOTODIODE AND AMPLIFIER

FEATURES

● WIDE BANDWIDTH, HIGH RESPONSIVITY:

R

F

BANDWIDTH

1MΩ 50kHz *150kHz

100MΩ 5kHz *13kHz

*with bootstrap buffer

● PHOTODIODE SIZE: 0.090 x 0.090 inch

(2.29 x 2.29mm)

● HIGH RESPONSIVITY: 0.45A/W

(650nm)

● LOW DARK ERRORS: 2mV max

● EXCELLENT SPECTRAL RESPONSE

● LOW QUIESCENT CURRENT: 400

µA

● TRANSPARENT 8-PIN DIP

APPLICATIONS

● MEDICAL INSTRUMENTATION

● LABORATORY INSTRUMENTATION

● POSITION AND PROXIMITY SENSORS

● PHOTOGRAPHIC ANALYZERS

● BARCODE SCANNERS

● SMOKE DETECTORS

R

F

2

OPT211

5

V

λ

78

1

3

V–V+

OUT

DESCRIPTION

The OPT211 is a monolithic photodiode with on-chip
FET-input transpedance amplifier, that provides wide
bandwidth at very high gains. Uncommitted input and
feedback nodes allow a variety of feedback options for
maximum versatility. Trade-offs in responsivity (gain),
bandwidth and SNR can easily be made.

The monolithic combination of photodiode and
transimpedance amplifier on a single chip eliminates
the problems commonly encountered in discrete de­signs such as leakage current errors, noise pickup and
gain peaking due to stray capacitance. The 0.09 x 0.09
inch photodiode is operated at zero bias for excellent
linearity and low dark current. Direct access to the
detector’s anode allows photodiode bootstrapping,
which increases speed performance.

The OPT211 operates over a wide supply range (±2.25V
to ±18V) and supply current is only 400µA. It is
packaged in a transparent plastic 8-pin DIP specified
for the 0°C to 70°C temperature range.

SPECTRAL RESPONSIVITY

Ultraviolet

0.5

0.4

0.3

0.2

0.1

Photodiode Responsivity (A/W)

0

Using External

1MΩ Resistor

100 200 300 400 500 600 700 800 900 1000 1100

Blue

Wavelength (nm)

Green

Yellow

Red

Infrared

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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-1258B Printed in U.S.A. January, 1995

SPECIFICATIONS

At TA = +25°C, VS = ±15V, λ = 650nm, external 1MΩ feedback resistor, circuit shown in Figure 1, unless otherwise noted.

OPT211P
PARAMETER CONDITIONS MIN TYP MAX UNITS
RESPONSIVITY

Photodiode Current 650nm 0.45 A/W
Unit-to-Unit Variation 650nm ±5%
Voltage Output λ = 650nm, R
Nonlinearity 0.01 % of FS
Photodiode Area (0.090 x 0.090 inches) 0.008 in

(2.29 x 2.29mm) 5.2 mm

DARK ERRORS, RTO

(1)

Offset Voltage, Output ±0.5 ±2mV

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

Voltage Noise, Dark Dark, f

= ±2.25V to ±18V 10 100 µV/V

S

B

FREQUENCY RESPONSE

Bandwidth Anode Grounded

Anode Bootstrapped

Rise Time, 10% to 90%, R

= 1MΩ Anode Grounded

F

Anode Bootstrapped

Settling Time, FS to Dark Anode Grounded

1% 10 µs

0.1% 25 µs

0.01% 30 µs

100% Overload Recovery Time FS to Dark (to 1%) 44 µs

OUTPUT

Voltage Output R

Capacitive Load, Stable Operation

(4)

Short-Circuit Current ±18 mA

POWER SUPPLY

Operating Voltage Range ±2.25 ± 15 ±18 V
Quiescent Current V

TEMPERATURE RANGE

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

θ

JA

NOTES: (1) Referred to Output. Includes all error sources. (2) See Figure 1. (3) See Figure 3. (4) See Figure 2.

= 1MΩ 0.45 V/µW

F

= 0.1Hz to 100kHz 1 mVrms

(2)

(3)

(2)

(3)

(2)

V

= ±5V 100 µs

S

V

= ±2.25V 240 µs

S

= 10kΩ (V+) – 1.25 (V+) – 1 V

L

R

= 5kΩ (V+) – 2 (V+) – 1.5 V

L

= 0V ±400 ±500 µA

OUT

50 kHz

150 kHz

5 µs
2 µs

250 pF

100 °C/W

2

2

PHOTODIODE SPECIFICATIONS

At TA = +25°C, λ = 650nm, unless otherwise noted.

Photodiode of OPT211

PARAMETER CONDITIONS MIN TYP MAX UNITS

Photodiode Area (0.090 x 0.090 inches) 0.008 in

(2.29 x 2.29mm) 5.2 mm

Current Responsivity λ = 650nm 0.45 A/W

865 µA/W/cm

Dark Current VD = 0V 500 fA

vs Temperature doubles every 10°C

Capacitance V

= 0V 600 pF

D

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.

®

OPT211

2

2

2

2

OP AMP SPECIFICATIONS

TA = +25°C, VS = ±15V, RL = 10kΩ, unless otherwise noted.

OPT211 Op Amp
PARAMETER CONDITIONS MIN TYP MAX UNITS
INPUT

Offset Voltage ±0.5 mV

vs Temperature ±5 µV/°C
vs Power Supply V

Input Bias Current ±1pA

= ±2.25V to ±18V 10 µV/V

S

vs Temperature doubles every 10°C

Input Impedance

Differential 10
Common-Mode 10

Common-Mode Input Voltage Range Linear Operation ±14.4 V

Common-Mode Rejection 106 dB

NOISE

Voltage Noise Density f = 10Hz 30 nV/√Hz

f = 100Hz 25 nV/√Hz

f = 1kHz 15 nV/√Hz

Current Noise Density f = 1kHz 0.8 fA/√Hz

OPEN-LOOP GAIN

Open-Loop Voltage Gain 120 dB

FREQUENCY RESPONSE

Gain-Bandwidth Product

(2)

Slew Rate 6V/µs
Settling Time 0.1% 4 µs

0.01% 5 µs

OUTPUT

Voltage Output R

Short-Circuit Current ±18 mA

= 10kΩ (V+) – 1.25 (V+) – 1 V

L

R

= 5kΩ (V+) – 2 (V+) – 1.5 V

L

POWER SUPPLY

Operating Voltage Range ±2.25 ±15 ±18 V
Quiescent Current I

= 0mA ±400 ±500 µA

O

NOTES: (1) Op amp specifications provided for information and comparison only. (2) Stable in gains ≥ 20V/V.

(1)

12

|| 3 Ω || pF

12

|| 3 Ω || pF

16 MHz

®

3

OPT211

PIN CONFIGURATIONS

Top View DIP

1

V+

2

–In

V–

NC

NOTE: (1) Photodiode location.

(1)

3
4

8
7
6
5

Common
PD Anode
NC
V

OUT

ABSOLUTE MAXIMUM RATINGS

Supply Voltage................................................................................... ±18V

Input Voltage Range ............................................................................ ±V

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)

PACKAGE INFORMATION

PRODUCT PACKAGE NUMBER

PACKAGE DRAWING

OPT211P 8-Pin DIP 006-1

NOTE: (1) For detailed drawing and dimension table, please see end of data
sheet, or Appendix C of Burr-Brown IC Data Book.

(1)

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.

S

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 OPT211 plastic
packages cannot meet flammability test, UL-94.

®

OPT211

4

RESPONSE vs INCIDENT ANGLE

Relative Response

Incident Angle (°)

0

1.0

0.8

0.6

0.4

0.2

0

±20 ±40 ±60 ±80

θ

Y

θ

X

1.0

0.8

0.6

0.4

0.2

0

θ

Y

θ

X

Plastic

DIP Package

TYPICAL PERFORMANCE CURVES

At TA = +25°C, VS = ±15V, λ = 650nm, external 1MΩ feedback resistor, circuit shown in Figure 1, 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)

TRANSIMPEDANCE vs FREQUENCY

100M

RF = 100MΩ

Dotted Line:
Bandwidth with
Bootstrap Buffer—

10M

RF = 10MΩ, CF = 1pF

1M

RF = 1MΩ, CF = 3pF

Transimpedance (V/A)

See Text.

(0.48A/W)

VOLTAGE RESPONSIVITY vs RADIANT POWER

10

1

= 100MΩ

F

R

0.1

Output Voltage (V)

0.01

= 10MΩ

F

R

R

= 1MΩ

F

λ = 650nm

100k

1k 10k 100k 1M

Frequency (Hz)

VOLTAGE RESPONSIVITY vs IRRADIANCE

10

1

= 100MΩ

F

0.1

Output Voltage (V)

0.01

R

= 10MΩ

F

R

= 1MΩ

F

R

0.001

-4

10

-3

10

10

Irradiance (W/m

0.001

-3

10

-2

10

-1

10

10

1

10

2

10

Radiant Power (µW)

QUIESCENT CURRENT vs TEMPERATURE

0.6

0.5
VS = ±15V

0.4

0.3

VS = ±2.25V

0.2

λ = 650nm

Quiescent Current (mA)

0.1

0

10

-1
2

)

10 10

-2

1

–50 –25 0 25 50 75 100 125

–75

Temperature (°C)

5

OPT211

®

TYPICAL PERFORMANCE CURVES (CONT)

At TA = +25°C, VS = ±15V, λ = 650nm, external 1MΩ feedback resistor, circuit shown in Figure 1, unless otherwise noted.

–2

10

Total Noise

0.1 Hz to

–3

10

Indicated BW

–4

10

RF = 100MΩ

–5

10

Noise Voltage (Vrms)

–6

10

RF = 10MΩ

–7

10

1 10 1k 10k 100k100

OUTPUT NOISE VOLTAGE

vs MEASUREMENT BANDWIDTH

OPT211 Anode

RF = 1MΩ

Grounded
OPT211 with Anode

Bootstrap Drive

Frequency (Hz)

STEP RESPONSE

= 1MΩ, Anode Grounded

R

F

1M

NOISE EFFECTIVE POWER

–8

10

–9

10

vs MEASUREMENT BANDWIDTH

λ = 650nm

Total Noise

0.1 Hz to

–10

10

10

Noise Effective Power (W)

10

10

10

Indicated BW

–11

–12

–13

–14

1 10 1k 10k 100k100

Frequency (Hz)

STEP RESPONSE

= 1MΩ, Bootstrap Buffer

R

F

1MΩ

10MΩ

100MΩ

OPT211 Anode
Grounded

OPT211 with Anode
Bootstrap Drive

1M

®

OPT211

6

APPLICATIONS INFORMATION

Figure 1 shows the basic connections required to operate the
OPT211. Applications with high impedance power supplies
may require decoupling capacitors located close to the
device pins as shown in Figure 1.

C

F

RF ≥ 330kΩ

2

I

D

λ

78

R

F

(Ω) (pF) (kHz)

330k 5.6 86

1M 3 50

10M 1

100M 0.3

NOTE: (1) Feedback resistor has approximately 1pF stray
capacitance. C
resistors. See text.

0.1µF 0.1µF

<1pF requires series-connected feedback

F

OPT211

13

V+

+15V

C

F

(1)

(1)

V–

–15V

5

Bandwidth

16

5

V

OUT

FIGURE 1. Basic Circuit Connections.

Output is zero volts with no light and increases with increas­ing illumination. Photodiode current is proportional to the
radiant power (watts) falling in the photodiode. At 650nm
wavelength (visible red) the photodiode responsivity is ap­proximately 0.45A/W. Responsivity at other wavelengths is
shown in the typical performance curve “Responsivity vs
Wavelength.”

The OPT211’s output voltage is the product of the photo­diode current and feedback resistor, (I

). The feedback

DRF

resistor must be greater than 330kΩ for proper stability. A
feedback capacitor, CF, must be connected as shown. Rec­ommended values are shown in Figure 1. Capacitor values
for other feedback resistances can be interpolated.

The OPT211 provides excellent performance with very high
feedback resistor values. To achieve maximum bandwidth
with R

≥ 10MΩ, good circuit layout is required. With

F

careful circuit board layout and a 10MΩ feedback resistor,
stray capacitance will provide approximately the correct
parallel capacitance for stable operation and widest band­width. For larger feedback resistor values, two resistors
connected in series and laid-out end-to-end will reduce the

stray capacitance to a few tenths of a picofarad. With
experimentation, circuit board traces can be used to produce
the necessary stray capacitance for proper compensation and
widest possible bandwidth.

The circuit in Figure 1 can drive capacitive loads up to
250pF. To drive load capacitance up to 1nF, connect R

and

1

the feedback components as shown in Figure 2.

DARK ERRORS

Dark error specifications include all error sources and are
tested with the circuit shown in Figure 1 using R

=1MΩ.

F

The dominate dark error source is the input offset voltage of
the internal op amp. The combination of photodiode dark
current and op amp input bias current is approximately

1.5pA at 25°C. Even with very large feedback resistors, this
contributes virtually no offset error. Dark current and input
bias current increase with temperature, doubling (approxi­mately) for each 10°C increase. At 70°C, dark current is
approximately 35pA. This would produce 3.5mV offset with
a 100MΩ feedback resistor.

Circuit board leakage currents can increase dark error. Use
clean assembly procedures to avoid contamination, particu­larly around the sensitive inverting input node (pin 2). Errors
due to leakage current from the V+ supply (pin 1) can be
eliminated by encircling the trace connecting to pin 2 with
a guard trace connected to ground.

IMPROVING BANDWIDTH

Bandwidth of the OPT211 can be increased with the feed­back buffer circuits shown in Figure 3. Driving the anode of
the photodiode (pin 7) in this manner reduces the effect of
the photodiode’s capacitance on signal bandwidth. This
“bootstrap drive” circuit boosts bandwidth by approximately
3x. Bandwidth achieved with various R
Figure 2. When using a bootstrap buffer, R

values is shown in

F

must be greater

F

or equal to 1MΩ for stable operation.

R

F

C

F

2

OPT211

R

1

175Ω

λ

78

0.1µF 0.1µF

13

V+

V–

5

V

CL≤1nF

OUT

FIGURE 2. Increasing C-Load Drive.

®

7

OPT211

To Pin 7

+15V

S
D

–15V

+15V

–15V

7.5kΩ

λ

R

6.8kΩ

R

1

Q

1

2N5116

78

Q

1

2N6427

1

(b)

Bootstrap

Buffer

2

(a)

From
Pin 2

RF ≥ 1MΩ

1

To Pin 7

C

F

OPT211

3

–15V+15V

OPA131

5

(c)

V

OUT

From
Pin 2

AC COUPLING

Some applications are concerned only with sensing variation
in light intensity. Simple capacitive coupling at the OPT211’s
output may be adequate. With large feedback resistors or
bright ambient light, however, the OPT211’s output may
saturate. The circuit in Figure 4 can reject very bright
ambient light, yet provide high AC gain for best signal-to­noise ratio. The output voltage is integrated and fed back to
the inverting input through R

. This drives the average (dc)

3

voltage at the output to zero. Application Bulletin AB-061
provides more details on this technique.

C

= C

1

R1 = R

f

–3dB

2
2

=

R3(2πR2C2)

=16Hz

λ

R

F

2

R

1MΩ

6

3

C

2

0.1µF

OPA177

RF = 10MΩ

OPT211

2

3

R

1MΩ

1

5

R

2

1MΩ

C

1

0.1µF

V

OUT

R

F

(Ω) (pF) (kHz)

330k Not Recommended

1M 1

10M <0.2

100M <0.2

NOTE: (1) Most resistors have approximately 1pF stray
capacitance. C
resistors. See text.

<1pF requires series-connected feedback

F

C

F

(1)

(1)
(1)

Bandwidth

150

42
13

FIGURE 3. Increasing Bandwidth with Bootstrap Buffer.

Gate or base current of the buffer transistor flows through
the feedback resistor, increasing the dark offset voltage. If
dark errors are important, use a FET transistor with picoamp
gate current. A P-channel FET is used to assure that the
anode is at ground potential or slightly negative.

If dark errors are not critical, an NPN Darlington transistor
can be used for a buffer as shown in Figure 3b. A FET-input
op amp connected as a buffer can be used as shown in Figure
3c, but its noise may degrade circuit performance slightly.
Bandwidth of the buffer should be 4MHz, minimum.

1

78

3

See Application Bulletin

V–V+

AB-061 for details.

FIGURE 4. Rejecting Ambient Light.

This circuit also corrects output offset produced by input
bias current of a buffer used to extend bandwidth. A
Darlington transistor can be used for a bandwidth-enhancing
bootstrap buffer in this circuit without creating offset error.

NOISE PERFORMANCE

Noise performance of the OPT211 is shown in typical
curves for various feedback resistor values. This curve
specifies the total noise measured from 0.1Hz to the indi­cated bandwidth. High frequency noise is reduced with the
bootstrap transistor buffer circuits shown in Figure 1. This
effect is shown on the typical curve.

Output noise of the OPT211 extends beyond the signal
bandwidth, especially for high feedback resistor values.
Signal-to-noise ratio can be improved by filtering the
OPT211’s output to a bandwidth equal to the signal band­width—see Figure 5.

®

OPT211

8

Best signal-to-noise ratio is achieved by using the highest
practical feedback resistor. This comes with the trade-off of
decreased bandwidth.

The noise performance of a photodetector is sometimes
characterized by its noise effective power (NEP). This is the
radiant power which would produce an output signal equal
to the output noise level. NEP has the units of radiant
power (W). A NEP curve is provided.

LIGHT SOURCE POSITIONING

The OPT211 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 OPT211 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 OPT211 would not
perform properly. The large (0.090 inch x 0.090 inch)

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 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 diffracted and scattered by the side of the package. These
effects are shown in the typical performance curve
“Responsivity vs Incident Angle.”

LINEARITY PERFORMANCE

The photodiode inside the OPT211 is designed to be operated
in the photoconductive mode (V

= 0V) for very linear

DIODE

operation with radiant power throughout a wide range.
Nonlinearity remains below approximately 0.05% up to
100µA photodiode current.

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.

Using Burr-Brown’s Application Bulletin No. AB-034

RF = 10MΩ

2

OPT211

5

2.94kΩ

λ

Sallen-Key

1

78

3

V–V+

FIGURE 5. Low Pass Filter for Improved Signal-to-Noise Ratio.

2-Pole Butterworth
f

= 20kHz

–3dB

Sallen-Key Low Pass Filter Designed

2.2nF

2

21kΩ

OPA131

3

470pF

6

V

O

®

9

OPT211