Datasheet AD629 (Analog Devices)

High Common-Mode Voltage, Difference Amplifier AD629 FEATURES FUNCTIONAL BLOCK DIAGRAM Improved replacement for: INA117P and INA117KU 21.1kΩ 380kΩ ±270 V common-mode voltage range REF(–) 1 8 NC 380kΩ Input protection to –IN 2 7 +VS ±500 V common mode 380kΩ +IN 3 6 OUTPUT ±500 V differential mode 20kΩ –V 4 5 S REF(+) Wide power supply range (±2.5 V to ±18 V) AD629
01 0 3-
±10 V output swing on ±12 V supply NC = NO CONNECT
078 0
1 mA maximum power supply current
Figure 1.
GENERAL DESCRIPTION HIGH ACCURACY DC PERFORMANCE 3 ppm maximum gain nonlinearity (AD629B)
The AD629 is a difference amplifier with a very high input,
20 μV/°C maximum offset drift (AD629A)
common-mode voltage range. It is a precision device that allows
10 μV/°C maximum offset drift (AD629B)
the user to accurately measure differential signals in the
10 ppm/°C maximum gain drift
presence of high common-mode voltages up to ±270 V.

The AD629 can replace costly isolation amplifiers in
EXCELLENT AC SPECIFICATIONS
applications that do not require galvanic isolation. The device
77 dB minimum CMRR @ 500 Hz (AD629A)
operates over a ±270 V common-mode voltage range and has
86 dB minimum CMRR @ 500 Hz (AD629B)
inputs that are protected from common-mode or differential
500 kHz bandwidth
mode transients up to ±500 V.
APPLICATIONS
The AD629 has low offset, low offset drift, low gain error drift, low common-mode rejection drift, and excellent CMRR over a
High voltage current sensing
wide frequency range.
Battery cell voltage monitors
The AD629 is available in die and packaged form featuring
Power supply current monitors Motor controls
8-lead PDIP and 8-lead SOIC packages. For all packages
Isolation
(including die) and grades, performance is guaranteed over the industrial temperature range of −40°C to +85°C.
100 ) 2mV/DIV B 95 d ( O 90 ) TI A IV R 85 /D N IO 80 2mV CT R ( JE 75 RRO RE E E D 70 UT O P -M T 65 N U O O M 60 M CO
03
55
02 0 0
60V/DIV
3- 3- 78 78
50
00 00
20 100 1k 10k 20k –240 –120 0 120 240 FREQUENCY (Hz) COMMON-MODE VOLTAGE (V)
Figure 2. Common-Mode Rejection Ratio vs. Frequency Figure 3. Error Voltage vs. Input Common-Mode Voltage
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Document Outline FEATURES APPLICATIONS FUNCTIONAL BLOCK DIAGRAM GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION APPLICATIONS BASIC CONNECTIONS SINGLE-SUPPLY OPERATION SYSTEM-LEVEL DECOUPLING AND GROUNDING USING A LARGE SENSE RESISTOR OUTPUT FILTERING OUTPUT CURRENT AND BUFFERING A GAIN OF 19 DIFFERENTIAL AMPLIFIER ERROR BUDGET ANALYSIS EXAMPLE 1 ERROR BUDGET ANALYSIS EXAMPLE 2 OUTLINE DIMENSIONS ORDERING GUIDE