REV. A
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a
AD629
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., 2000
High Common-Mode Voltage
Difference Amplifier
FEATURES
Improved Replacement for:
INA117P and INA117KU
H11550270 V Common-Mode Voltage Range
Input Protection to:
H11550500 V Common Mode
H11550500 V Differential
Wide Power Supply Range (H115502.5 V to H1155018 V)
H1155010 V Output Swing on H1155012 V Supply
1 mA Max Power Supply Current
HIGH ACCURACY DC PERFORMANCE
3 ppm Max Gain Nonlinearity
20 H9262V/H11543C Max Offset Drift (AD629A)
10 H9262V/H11543C Max Offset Drift (AD629B)
10 ppm/H11543C Max Gain Drift
EXCELLENT AC SPECIFICATIONS
77 dB Min CMRR @ 500 Hz (AD629A)
86 dB Min CMRR @ 500 Hz (AD629B)
500 kHz Bandwidth
APPLICATIONS
High Voltage Current Sensing
Battery Cell Voltage Monitor
Power Supply Current Monitor
Motor Control
Isolation
FUNCTIONAL BLOCK DIAGRAM
8-Lead Plastic Mini-DIP (N) and SOIC (R) Packages
1
2
3
4
8
7
6
5
21.1kH9024
380kH9024
380kH9024
380kH9024
20kH9024
REF(–)
–IN
+IN
–V
S
NC
+V
S
OUTPUT
REF(+)
AD629
NC = NO CONNECT
GENERAL DESCRIPTION
The AD629 is a difference amplifier with a very high input
common-mode voltage range. It is a precision device that
allows the user to accurately measure differential signals in the
presence of high common-mode voltages up to ±270 V.
The AD629 can replace costly isolation amplifiers in applications
that do not require galvanic isolation. The device will operate
over a ±270 V common-mode voltage range and has inputs
that are protected from common-mode or differential mode
transients up to ±500 V.
The AD629 has low offset, low offset drift, low gain error drift,
as well as low common-mode rejection drift, and excellent CMRR
over a wide frequency range.
The AD629 is available in low-cost, plastic 8-lead DIP and
SOIC packages. For all packages and grades, performance is
guaranteed over the entire industrial temperature range from
–40°C to +85°C.
FREQUENCY – Hz
100
50
20 100
COMMON-MODE REJECTION RATIO
–
dB
1k 10k 20k
95
90
85
80
75
70
65
60
55
Figure 1. Common-Mode Rejection Ratio vs. Frequency
60V/DIV
2mV/DIV
–240 –120 0 120 240
COMMON-MODE VOLTAGE – Volts
OUTPUT ERROR
–
2mV/DIV
Figure 2. Common-Mode Operating Range. Error Voltage
vs. Input Common-Mode Voltage