Analog Devices AD8691 2 a Datasheet

Low Cost, Low Noise, CMOS Rail-to-Rail

FEATURES

Offset voltage: 400 µV typ
Low offset voltage drift: 6 µV/°C max (AD8692)
Very low input bias currents: 1 pA max
Low noise: 8 nV/√Hz
Low distortion: 0.0006%
Wide bandwidth: 10 MHz
Unity-gain stable
Single-supply operation: 2.7 V to 6 V

APPLICATIONS

Photodiode amplification
Battery-powered instrumentation
Medical instruments
Multipole filters
Sensors
Portable audio devices

Output Operational Amplifiers

AD8691/AD8692

PIN CONFIGURATIONS

OUT

1

AD8691

V–

2

TOP VIEW

(Not to Scale)

3

+IN

Figure 1. 5-Lead TSOT

OUT A

+IN A

AD8691

1

V–

2

3

Figure 2. 5-Lead SC70

OUT A

1

AD8692

2

–IN A
+IN A

V–

TOP VIEW

3

(Not to Scale)

4

Figure 3. 8-Lead MSOP

5

3

5

4

8
7
6
5

V+

–IN

V+

–IN

V+
OUT B
–IN B
+IN B

04991-030

04991-031

04991-001

GENERAL DESCRIPTION

The AD8691 and AD8692 are low cost, single and dual rail-to­rail output, single-supply amplifiers featuring low offset and
input voltages, low current noise, and wide signal bandwidth.
The combination of low offset, low noise, very low input bias
currents, and high speed make these amplifiers useful in a wide
variety of applications. Filters, integrators, photodiode amplifiers,
and high impedance sensors all benefit from this combination
of performance features. Audio and other ac applications
benefit from the wide bandwidth and low distortion of these
devices.

Rev. A

Information furnished by Analog Devices is believed to be accurate and reliable.
However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective owners.

OUT A

–IN A
+IN A

V–

1

AD8692

2
3

TOP VIEW

(Not to Scale)

4

8
7
6
5

V+
OUT B
–IN B
+IN B

04991-002

Figure 4. 8-Lead SOIC

Applications for these amplifiers include PA controls, laser
diode control loops, portable and loop-powered instrumentation,
audio amplification for portable devices, and ASIC input and
output amplifiers.

The small SC70 and TSOT package options for the AD8691
allow it to be placed next to sensors, thereby reducing external
noise pickup.

The AD8691 and AD8692 are specified over the extended
industrial temperature range of −40°C to +125°C. The AD8691
is available in 5-lead SC70 and TSOT packages. The AD8692 is
available in 8-lead MSOP and narrow SOIC surface-mount
packages.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone]
Fax: [phone] © 2005 Analog Devices, Inc. All rights reserved.

www.analog.com

AD8691/AD8692

TABLE OF CONTENTS

Electrical Characteristics................................................................. 3

Typical Perfor m a n c e C haracter i s t ic s ..............................................6

Absolute Maximum Ratings............................................................ 5

Thermal Characteristics .............................................................. 5

ESD Caution.................................................................................. 5

REVISION HISTORY

1/05 — Rev. 0 to Rev. A

Added AD8691 ...................................................................Universal

Changes to Features.......................................................................... 1

Added Figure 1 and Figure 2........................................................... 1

Changes to Electrical Characteristics ............................................ 3

Changes to Figure 6 caption............................................................ 6

Changes to Figure 9.......................................................................... 6

Updated Outline Dimensions....................................................... 11

Changes to Ordering Guide.......................................................... 11

10/04—Revision 0: Initial Version

Outline Dimensions ....................................................................... 11

Ordering Guide .......................................................................... 12

Rev. A | Page 2 of 12

AD8691/AD8692

ELECTRICAL CHARACTERISTICS

VS = 2.7 V, VCM = VS/2, TA = 25°C, unless otherwise noted.

Table 1.

Parameter Symbol Conditions Min Typ Max Unit

INPUT CHARACTERISTICS

Offset Voltage V

OS

V
Input Bias Current I

B

−40°C < TA < +85°C 50 pA

−40°C < TA < +125°C 260 pA
Input Offset Current I

OS

−40°C < TA < +85°C 20 pA

−40°C < TA < +125°C 75 pA
Input Voltage Range −0.3 +1.6 V
Common-Mode Rejection Ratio CMRR VCM = −0.3 V to +1.6 V 70 90 dB
V
Large Signal Voltage Gain A

VO

Offset Voltage Drift ∆VOS/∆T

AD8691 2 12 µV/°C
AD8692 1.3 6 µV/°C

OUTPUT CHARACTERISTICS

Output Voltage High V

OH

−40°C < TA < +125°C 2.6 V
Output Voltage Low V

OL

−40°C < TA < +125°C 50 mV
Short-Circuit Current I
Closed-Loop Output Impedance Z

SC

OUT

POWER SUPPLY

Power-Supply Rejection Ratio PSRR VS = 2.7 V to 5.5 V 80 95 dB

−40°C < TA < +125°C 75 95 dB
Supply Current/Amplifier I

SY

−40°C < TA < +125°C 1.2 mA

DYNAMIC PERFORMANCE

Slew Rate SR RL = 2 kΩ 5 V/µs
Settling Time t

S

Gain Bandwidth Product GBP 10 MHz
Phase Margin Øo 60 Degrees
Total Harmonic Distortion + Noise THD + N

NOISE PERFORMANCE

Voltage Noise e
Voltage Noise Density e
e
Current Noise Density i

n p-p

n

n

n

VCM = −0.3 V to +1.6 V 0.4 2.0 mV

= −0.1 V to +1.6 V; −40°C < TA < +125°C 3.0 mV

CM

0.2 1 pA

0.1 0.5 pA

= −0.1 V to +1.6 V; −40°C < TA < +125°C 65 85 dB

CM

RL = 2 kΩ, VO = 0.5 V to 2.2 V 90 250 V/mV

IL = 1 mA 2.64 2.66 V

IL = 1 mA 25 40 mV

±20 mA
f = 1 MHz, AV = 1 12 Ω

VO = 0 V 0.85 0.95 mA

To 0.01% 1 µs

G = 1, R

= 600 Ω, f = 1 kHz, VO = 250 mV p-p

L

0.003 %

f = 0.1 Hz to 10 Hz 1.6 3.0 µV p-p
f = 1 kHz 8 12 nV/√Hz
f = 10 kHz 6.5 nV/√Hz
f = 1 kHz 0.05 pA/√Hz

Rev. A | Page 3 of 12

AD8691/AD8692

VS = 5.0 V, VCM = VS/2, TA = 5°C, unless otherwise noted.

Table 2.

A Grade
Parameter Symbol Conditions Min Typ Max Unit

INPUT CHARACTERISTICS

Offset Voltage V

OS

V
Input Bias Current I

B

−40°C < TA < +85°C 50 pA

−40°C < TA < +125°C 260 pA
Input Offset Current I

OS

−40°C < TA < +85°C 20 pA

−40°C < TA < +125°C 75 pA
Input Voltage Range

Common-Mode Rejection Ratio CMRR VCM = −0.3 V to +3.9 V 75 95 dB
V
Large Signal Voltage Gain A
Offset Voltage Drift

∆V

VO

OS

AD8691 2 12 µV/°C
AD8692 1.3 6 µV/°C

OUTPUT CHARACTERISTICS

Output Voltage High V

OH

I

−40°C to +125°C 4.6 V
Voltage Low V

OL

I

−40°C to +125°C 290 mV
Short-Circuit Current I
Closed-Loop Output Impedance Z

SC

OUT

POWER SUPPLY

Power Supply Rejection Ratio PSRR VS = 2.7 V to 5.5 V 80 95 dB

−40°C < TA < +125°C 75 95 dB
Supply Current/Amplifier I

SY

−40°C < TA < +125°C 1.3 mA

DYNAMIC PERFORMANCE

Slew Rate SR RL = 2 kΩ 5 V/µs
Settling Time t
Full Power Bandwidth BW

S

P

Gain Bandwidth Product GBP 10 MHz
Phase Margin Øo 65 Degrees
Total Harmonic Distortion + Noise THD + N

NOISE PERFORMANCE

Voltage Noise e
Voltage Noise Density e
e
Current Noise Density i

n p-p

n

n

n

VCM = −0.3 V to +3.9 V 0.4 2.0 mV

= −0.1 V to +3.9 V; −40°C < TA < +125°C 3.0 mV

CM

0.2 1 pA

0.1 0.5 pA

+3.9 V

−0.3

= −0.1 V to +3.9 V; −40°C < TA < +125°C 70 95 dB

CM

VO = 0.5 V to 4.5 V, RL = 2 kΩ, VCM = 0 V 250 2000 V/mV

/∆T

IL = 1 mA 4.96 4.98 V

= 10 mA 4.7 4.78 V

L

IL = 1 mA 16.5 40 mV

= 10 mA 165 210 mV

L

±80 mA
f = 1 MHz, AV = 1 10 Ω

VO = 0 V 0.95 1.05 mA

To 0.01% 1 µs
<1% distortion 360 kHz

G = 1, R

= 600 Ω, f = 1 kHz, VO = 1 V p-p

L

0.0006 %

f = 0.1 Hz to 10 Hz 1.6 3.0 µV p-p
f = 1 kHz 8 12
f = 10 kHz 6.5
f = 1 kHz 0.05

nV/√Hz
nV/√Hz
pA/√Hz

Rev. A | Page 4 of 12