a
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 V/ C V
OS
Drift
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
Ultralow Distortion,
Ultralow Noise Op Amp
AD797*
CONNECTION DIAGRAM
8-Pin Plastic Mini-DIP (N),
Cerdip (Q) and SOIC (R) Packages
OFFSET NULL
–IN
+IN
–V
S
1
2
3
4
AD797
8
7
6
DECOMPENSATION &
DISTORTION
NEUTRALIZATION
+V
S
OUTPUT
OFFSET NULL
TOP VIEW
5
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
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
Hz
4
–100
0.001
INPUT VOLTAGE NOISE – nV/
THD – dB
–110
0.0003
2
1
–120
MEASUREMENT
LIMIT
0.0001
0
10
100
1k
10k
100k
1M
10M
FREQUENCY – Hz
–130
100
300
1k
3k
10k
FREQUENCY – Hz
30k
100k
300k
AD797 Voltage Noise Spectral Density
*Patent
pending.
THD vs. Frequency
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.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700
Fax: 617/326-8703
THD – %
3
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