ANALOG DEVICES AD820 Service Manual
Single-Supply, Rail-to-Rail,
AD820
NC = NO CONNECT
NULL
1
–IN
2
+IN
3
–V
S
4
NC
8
+V
S
7
V
OUT
6
NULL
5
AD820
TOP VIEW
(Not to Scale)
00873-001
NC = NO CONNECT
NC
1
–IN
2
+IN
3
–V
S
4
NC
8
+V
S
7
V
OUT
6
NC
5
AD820
TOP VIEW
(Not to Scale)
00873-002
00873-004
100
90
10
0%
1V1V
1V
20µs
FEATURES
True single-supply operation
Output swings rail-to-rail
Input voltage range extends below ground
Single-supply capability from 5 V to 30 V
Dual-supply capability from ±2.5 V to ±15 V
Excellent load drive
Capacitive load drive up to 350 pF
Minimum output current of 15 mA
Excellent ac performance for low power
800 μA maximum quiescent current
Unity-gain bandwidth: 1.8 MHz
Slew rate of 3 V/μs
Excellent dc performance
800 μV maximum input offset voltage
2 μV/°C typical offset voltage drift
25 pA maximum input bias current
Low noise: 13 nV/√Hz @ 10 kHz
APPLICATIONS
Battery-powered precision instrumentation
Photodiode preamps
Active filters
12-bit to 14-bit data acquisition systems
Medical instrumentation
Low power references and regulators
Low Power, FET Input Op Amp
PIN CONFIGURATIONS
Figure 1. 8-Lead PDIP
Figure 2. 8-Lead SOIC_N and 8-Lead MSOP
GENERAL DESCRIPTION
The AD820 is a precision, low power FET input op amp that
can operate from a single supply of 5 V to 36 V, or dual supplies
of ±2.5 V to ±18 V. It has true single-supply capability, with an
input voltage range extending below the negative rail, 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 maximum, offset voltage drift of
2 μV/°C, typical input bias currents below 25 pA, and low input
voltage noise provide dc precision with source impedances up
to 1 GΩ. 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 outstanding load drive capability, results in an exceptionally
versatile amplifier for the single-supply user.
Rev. H
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 par ties 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.
The AD820 is available in two performance grades. The A and
B grades are rated over the industrial temperature range of
−40°C to +85°C. The AD820 is offered in three 8-lead package
options: plastic DIP (PDIP), surface mount (SOIC) and (MSOP).
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113 ©1996–2011 Analog Devices, Inc. All rights reserved.
Figure 3. Gain-of-2 Amplifier; V
= 5 V, 0 V, VIN = 2.5 V Sine Centered at 1.25 V
S
www.analog.com
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