CONNECTION DIAGRAM

8-Pin Plastic Mini-DIP (N),

Cerdip (Q) and SOIC (R) Packages

1

2

3

4

8

7

6

5

AD797

DECOMPENSATION &

DISTORTION

NEUTRALIZATION

OUTPUT

OFFSET NULL

–IN

+IN

+V

S

–V

S

OFFSET NULL

TOP VIEW

REV. C

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

Ultralow Distortion,

Ultralow Noise Op Amp

AD797*

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

Tel: 617/329-4700

Fax: 617/326-8703

FEATURES

Low Noise

0.9 nV/

√Hz typ (1.2 nV/√Hz max) Input Voltage

Noise at 1 kHz

50 nV p-p Input Voltage Noise, 0.1 Hz to 10 Hz

Low Distortion

–120 dB Total Harmonic Distortion at 20 kHz

Excellent AC Characteristics

800 ns Settling Time to 16 Bits (10 V Step)

110 MHz Gain Bandwidth (G = 1000)

8 MHz Bandwidth (G = 10)

280 kHz Full Power Bandwidth at 20 V p-p

20 V/ s Slew Rate

Excellent DC Precision

80

V max Input Offset Voltage

1.0

Specified for

5 V and

15 V Power Supplies

High Output Drive Current of 50 mA

APPLICATIONS

Professional Audio Preamplifiers

IR, CCD, and Sonar Imaging Systems

Spectrum Analyzers

Ultrasound Preamplifiers

Seismic Detectors

ADC/DAC Buffers

PRODUCT DESCRIPTION

The AD797 is a very low noise, low distortion operational

amplifier ideal for use as a preamplifier. The low noise of

0.9 nV/

√Hz and low total harmonic distortion of –120 dB at

audio bandwidths give the AD797 the wide dynamic range

5

0

10M

3

1

100

2

10

4

1M

100k

10k

1k

FREQUENCY – Hz

AD797 Voltage Noise Spectral Density

*Patent pending.

necessary for preamps in microphones and mixing consoles.

Furthermore, the AD797’s excellent slew rate of 20 V/

µs and

110 MHz gain bandwidth make it highly suitable for low fre-

quency ultrasound applications.

The AD797 is also useful in IR and Sonar Imaging applications

where the widest dynamic range is necessary. The low distor-

tion and 16-bit settling time of the AD797 make it ideal for

buffering the inputs to

Σ∆ ADCs or the outputs of high resolu-

tion DACs especially when they are used in critical applications

such as seismic detection and spectrum analyzers. Key features

such as a 50 mA output current drive and the specified power

supply voltage range of

±5 to ±15 volts make the AD797 an

excellent general purpose amplifier.

–90

–130

300k

–120

300

100

–110

–100

100k

30k

10k

3k

1k

FREQUENCY – Hz

MEASUREMENT

LIMIT

0.001

0.0003

0.0001

THD vs. Frequency