Very High Common-Mode Voltage
Precision Difference Amplifier
AD8479
Data Sheet
FEATURES
FUNCTIONAL BLOCK DIAGRAM
AD8479
600 V common-mode voltage range
Rail-to-rail output
REF(–)
1
NC
+V
8
7
6
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
S
1MΩ
1MΩ
–IN
+IN
2
3
OUTPUT
REF(+)
–V
S
4
5
High accuracy dc performance
5 ppm maximum gain nonlinearity
10 µV/°C maximum offset voltage drift
5 ppm/°C maximum gain drift
NOTES
1. NC = NO CONNECT. DO NOT CONNECT TO THIS PIN.
Figure 1.
APPLICATIONS
800
600
High voltage current sensing
Battery cell voltage monitors
Power supply current monitors
Motor controls
V
= ±15V
S
400
V
= ±5V
S
200
Isolation
0
GENERAL DESCRIPTION
–200
–400
–600
–800
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
–20
–15
–10
–5
0
5
10
15
20
V
(V)
OUT
a
600 V common-mode voltage range and has inputs that are
Figure 2. Input Common-Mode Voltage vs. Output Voltage
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.
Rev. 0
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