Single-Supply, Rail-to-Rail,
Low Power, FET Input Op Amp
AD820
FEATURES
PIN CONFIGURATIONS
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
NULL 1
NC
8
AD820
7
+VS
6
VOUT
5
NULL
–VS 4
TOP VIEW
(Not to Scale)
00873-001
–IN 2
+IN 3
NC = NO CONNECT
Figure 1. 8-Lead PDIP
NC 1
NC
–IN 2
7
+VS
+IN 3
6
VOUT
5
NC
–VS 4
TOP VIEW
(Not to Scale)
NC = NO CONNECT
00873-002
8
AD820
Figure 2. 8-Lead SOIC_N and 8-Lead MSOP
APPLICATIONS
Battery-powered precision instrumentation
Photodiode preamps
Active filters
12-bit to 14-bit data acquisition systems
Medical instrumentation
Low power references and regulators
GENERAL DESCRIPTION
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.
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).
1V
1V
20µs
100
90
10
0%
1V
00873-004
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.
Figure 3. Gain-of-2 Amplifier; VS = 5 V, 0 V, VIN = 2.5 V Sine Centered at 1.25 V
Rev. H
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