High Common-Mode Voltage, Difference Amplifier

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 operates 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, low common-mode rejection drift, and excellent CMRR over a wide frequency range.

The AD629 is available in low cost, 8-lead PDIP and 8-lead SOIC packages. For all packages (including die) and grades, performance is guaranteed over the industrial temperature range of −40°C to +85°C.

Applications

* High voltage current sensing

* Battery cell voltage monitors

* Power supply current monitors

* Motor controls

* Isolation

* Improved replacement for: INA117P and INA117KU

* ±270 V common-mode voltage range

* Input protection to

±500 V common mode

±500 V differential mode

Wide power supply range (±2.5 V to ±18 V)

±10 V output swing on ±12 V supply

1 mA maximum power supply current

* HIGH ACCURACY DC PERFORMANCE

3 ppm maximum gain nonlinearity (AD629B)

20 μV/°C maximum offset drift (AD629A)

10 μV/°C maximum offset drift (AD629B)

10 ppm/°C maximum gain drift

* EXCELLENT AC SPECIFICATIONS

77 dB minimum CMRR @ 500 Hz (AD629A)

86 dB minimum CMRR @ 500 Hz (AD629B)

500 kHz bandwidth