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 61.5 V to 618 V
Excellent Load Drive
Capacitive Load Drive Up to 350 pF
Minimum Output Current of 15 mA
Excellent AC Performance for Low Power
800 mA Max Quiescent Current
Unity Gain Bandwidth: 1.8 MHz
Slew Rate of 3.0 V/ms
Excellent DC Performance
800 mV Max Input Offset Voltage
1 mV/8C 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
98765432
INPUT BIAS CURRENT – pA
NUMBER OF UNITS
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 m V max, offset voltage drift of 1 m V/ 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/m s slew rate are provided for a low supply current of
800 m A. 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).
Figure 2. Gain of +2 Amplifier; V
S
= +5, 0, V
IN
= 2.5 V Sine
Centered at 1.25 Volts
1
2
3
4
8
7
6
5
TOP VIEW
(Not to Scale)
AD820NULL
–IN
+IN
–V
S
NC
+V
S
V
OUT
NULL
1
2
3
4
8
7
6
5
TOP VIEW
(Not to Scale)
AD820NC
–IN
+IN
–V
S
NC
+V
S
V
OUT
NC
NC = NO CONNECT