Very High Common-Mode Voltage
Precision Difference Amplifier
Data Sheet
Rev. A Document Feedback
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FEATURES
±600 V common-mode voltage range
Rail-to-rail output
Fixed gain of 1
Wide power supply range of ±2.5 V to ±18 V
550 μA typical power supply current
Excellent ac specifications
90 dB minimum CMRR
130 kHz bandwidth
High accuracy dc performance
5 ppm maximum gain nonlinearity
10 µV/°C maximum offset voltage drift
5 ppm/°C maximum gain drift
APPLICATIONS
High voltage current sensing
Battery cell voltage monitors
Power supply current monitors
Motor controls
Isolation
FUNCTIONAL BLOCK DIAGRAM
2
3
4
1
7
6
8
REF(–)
–IN
1MΩ
AD8479
1MΩ
+IN
–V
S
NC
NOTES
1. NC = NO CONNECT. DO NOT CONNECT TO THIS PIN.
+V
S
OUTPUT
11118-001
5
REF(+)
Figure 1.
GENERAL DESCRIPTION
The AD8479 is a difference amplifier with a very high input
common-mode voltage range. The AD8479 is a precision device
that allows the user to accurately measure differential signals in
the presence of high common-mode voltages up to ±600 V.
The AD8479 can replace costly isolation amplifiers in applications
that do not require galvanic isolation. The device operates over
a ±600 V common-mode voltage range and has inputs that are
protected from common-mode or differential mode transients
up to ±600 V.
The AD8479 has low offset voltage, low offset voltage drift,
low gain drift, low common-mode rejection drift, and excellent
common-mode rejection ratio (CMRR) over a wide frequency
range.
The AD8479 is available in a space-saving 8-lead SOIC package
and is operational over the −40°C to +125°C temperature range.
–800
–600
–400
–200
0
200
400
600
800
–20
–15 –10 –5
0 5
10 15 20
COMMON-MODE VOLTAGE (V)
V
OUT
(V)
V
S
=
±15V
V
S
= ±
5V
11118-
1
10
Figure 2. Input Common-Mode Voltage vs. Output Voltage
