CONNECTION DIAGRAMS

8-Lead Plastic Mini-DIP

8-Lead SOIC

REV. B

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

which may result from its use. No license is granted by implication or

otherwise under any patent or patent rights of Analog Devices.

a

Single Supply, Rail to Rail

Low Power FET-Input Op Amp

AD820

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

Tel: 781/329-4700

World Wide Web Site: http://www.analog.com

Fax: 781/326-8703

© Analog Devices, Inc., 1999

FEATURES

True Single Supply Operation

Output Swings Rail-to-Rail

Input Voltage Range Extends Below Ground

Single Supply Capability from +3 V to +36 V

Dual Supply Capability from

1.5 V to

18 V

Excellent Load Drive

Capacitive Load Drive Up to 350 pF

Minimum Output Current of 15 mA

Excellent AC Performance for Low Power

800

A Max Quiescent Current

Unity Gain Bandwidth: 1.8 MHz

Slew Rate of 3.0 V/ s

Excellent DC Performance

800

V Max Input Offset Voltage

1

V/ C Typ Offset Voltage Drift

25 pA Max Input Bias Current

Low Noise

13 nV/

√Hz @ 10 kHz

APPLICATIONS

Battery Powered Precision Instrumentation

Photodiode Preamps

Active Filters

12- to 14-Bit Data Acquisition Systems

Medical Instrumentation

Low Power References and Regulators

PRODUCT DESCRIPTION

The AD820 is a precision, low power FET input op amp that

can operate from a single supply of +3.0 V to 36 V, or dual

supplies of

±1.5 V to ±18 V. It has true single supply capability

with an input voltage range extending below the negative rail,

50

0

10

15

5

1

10

0

30

20

25

35

40

45

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8

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3

2

INPUT BIAS CURRENT – pA

Figure 1. Typical Distribution of Input Bias Current

allowing the AD820 to accommodate input signals below

ground in the single supply mode. Output voltage swing extends

to within 10 mV of each rail providing the maximum output

dynamic range.

Offset voltage of 800

µV max, offset voltage drift of 1 µV/°C, typ

input bias currents below 25 pA and low input voltage noise

provide dc precision with source impedances up to a Gigaohm.

1.8 MHz unity gain bandwidth, –93 dB THD at 10 kHz and

3 V/

µs slew rate are provided for a low supply current of

800

µA. The AD820 drives up to 350 pF of direct capacitive

load and provides a minimum output current of 15 mA. This

allows the amplifier to handle a wide range of load conditions.

This combination of ac and dc performance, plus the outstand-

ing load drive capability, results in an exceptionally versatile

amplifier for the single supply user.

The AD820 is available in three performance grades. The A and

B grades are rated over the industrial temperature range of

–40

°C to +85°C. There is 3 V grade—the AD820A-3V, rated

over the industrial temperature range.

The AD820 is offered in two varieties of 8-lead package: plastic

DIP, and surface mount (SOIC).

Centered at 1.25 Volts

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2

3

4

8

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5

TOP VIEW

(Not to Scale)

AD820

NULL

–IN

+IN

NC

NULL

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3

4

8

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5

TOP VIEW

(Not to Scale)

AD820

NC

–IN

+IN

NC

NC

NC = NO CONNECT