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