High Common-Mode Voltage
Difference Amplifier
a
AD629
FUNCTIONAL BLOCK DIAGRAM
FEATURES
Improved Replacement for:
INA117P and INA117KU
8-Lead Plastic Mini-DIP (N) and SOIC (R) Packages
؎270 V Common-Mode Voltage Range
Input Protection to:
؎500 V Common Mode
21.1k⍀
380k⍀
380k⍀
380k⍀
20k⍀
8
7
6
5
NC
+V
1
2
3
4
REF(–)
–IN
S
؎500 V Differential
+IN
OUTPUT
REF(+)
Wide Power Supply Range (؎2.5 V to ؎18 V)
؎10 V Output Swing on ؎12 V Supply
1 mA Max Power Supply Current
–V
S
AD629
NC = NO CONNECT
HIGH ACCURACY DC PERFORMANCE
3 ppm Max Gain Nonlinearity
20 V/؇C Max Offset Drift (AD629A)
10 V/؇C Max Offset Drift (AD629B)
10 ppm/؇C Max Gain Drift
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.
EXCELLENT AC SPECIFICATIONS
77 dB Min CMRR @ 500 Hz (AD629A)
86 dB Min CMRR @ 500 Hz (AD629B)
500 kHz Bandwidth
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.
APPLICATIONS
High Voltage Current Sensing
Battery Cell Voltage Monitor
Power Supply Current Monitor
Motor Control
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.
Isolation
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.
100
95
90
85
80
75
70
65
60
55
50
2mV/DIV
60V/DIV
–240
–120
COMMON-MODE VOLTAGE – Volts
0
120
240
20
100
1k
10k 20k
FREQUENCY – Hz
Figure 1. Common-Mode Rejection Ratio vs. Frequency
Figure 2. Common-Mode Operating Range. Error Voltage
vs. Input Common-Mode Voltage
REV. A
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.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781/329-4700
Fax: 781/326-8703
World Wide Web Site: http://www.analog.com
© Analog Devices, Inc., 2000