Low Power, Rail-to-Rail Output

Precision JFET Amplifier

AD8641

Rev. 0

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.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781.329.4700

www.analog.com

Fax: 781.326.8703

© 2004 Analog Devices, Inc. All rights reserved.

FEATURES

Low supply current: 250 µA max

Very low input bias current: 1 pA max

Low offset voltage: 750 µV max

Single-supply operation: 5 V to 26 V

Dual-supply operation: ±2.5 V to ±13 V

Rail-to-rail output

Unity gain stable

No phase reversal

SC70 package

APPLICATIONS

Line-/battery-powered instruments

Photodiode amplifiers

Precision current sensing

Medical instrumentation

Industrial controls

Precision filters

Portable audio

ATE

OUT

1

+IN

3

VEE

2

VCC

5

–IN

4

AD8641

TOP VIEW

(Not to Scale)

Figure 1. 5-Lead SC70 (KS-5)

NC

1

–IN

2

+IN

3

VEE

4

NC

8

VCC

7

OUT

6

NC

5

AD8641

TOP VIEW

(Not to Scale)

NC = NO CONNECT

Figure 2. 8-Lead SOIC (R-8)

GENERAL DESCRIPTION

The AD8641 is a low power, precision JFET input amplifier

featuring extremely low input bias current and rail-to-rail

output. The ability to swing nearly rail-to-rail at the input and

rail-to-rail at the output enables designers to buffer CMOS

DACs, ASICs, and other wide output swing devices in single-

supply systems. The outputs remain stable with capacitive loads

of more than 500 pF.

The AD8641 is suitable for applications utilizing multichannel

boards that require low power to manage heat. Other applica-

tions include photodiodes, ATE reference level drivers, battery

management, and industrial controls.

The AD8641 is fully specified over the extended industrial

temperature range of –40° to +125°C. The AD8641 is available

in 5-lead SC70 and 8-lead SOIC lead-free packages.