GENERAL DESCRIPTION
The AD8420 is a low cost, micropower, wide supply range, instrumentation amplifier with a rail-to-rail output and a novel architecture that allows for extremely flexible design. It is optimized to amplify small differential voltages in the presence of large common-mode signals.
The AD8420 is based on an indirect current feedback architecture that gives it an excellent input common-mode range. Unlike conventional instrumentation amplifiers, the AD8420 can easily amplify signals at or even slightly below ground without requiring dual supplies. The AD8420 has rail-to-rail output, and the output voltage swing is completely independent of the input common mode voltage.

FEATURES
   Maximum supply current: 90 μA
   Minimum CMRR: 100 dB
   Drives heavy capacitive loads: ~700 pF
   Rail-to-rail output
   Input voltage range goes below ground
   Gain set with 2 external resistors
      Can achieve low gain drift at any gain
   Very wide power supply range
      Single supply: 2.7 V to 36 V
      Dual supply: ±2.7 V to ±18 V
   Bandwidth (G = 100): 2.5 kHz
   Input voltage noise: 55 nV/√Hz
   High dc precision
      Maximum offset voltage: 125 μV
      Maximum offset drift: 1 μV/°C
   Maximum differential input voltage: ±1 V
   8-lead MSOP package

APPLICATIONS
   Bridge amplifiers
   Pressure measurement
   Medical instrumentation
   Portable data acquisition
   Multichannel systems