GENERAL DESCRIPTION

The AD8422 is a high precision, low power, low noise, rail-to-rail instrumentation amplifier that delivers the best performance per unit microampere in the industry. The AD8422 processes signals with ultralow distortion performance that is load independent over its full output range.

The AD8422 is the third generation development of the industry standard AD620. The AD8422 employs new process technologies and design techniques to achieve higher dynamic range and lower errors than its predecessors, while consuming less than one-third of the power. The AD8422 uses the high performance pinout introduced by the AD8221.

Very low bias current makes the AD8422 error-free with high source impedance, allowing multiple sensors to be multiplexed to the inputs. Low voltage noise and low current noise make the AD8422 an ideal choice for measuring a Wheatstone bridge.

FEATURES

  Low power: 330 µA maximum quiescent current

  Rail-to-rail output

  Low noise and distortion

     8 nV/√Hz maximum input voltage noise at 1 kHz

     0.15 µV p-p RTI noise (G = 100)

     0.5 ppm nonlinearity with 2 kΩ load (G = 1)

  Excellent ac specifications

     80 dB minimum CMRR at 7 kHz (G = 1)

     2.2 MHz bandwidth (G = 1)

  High precision dc performance (AD8422BRZ)

     150 dB minimum CMRR (G = 1000)

     0.04% maximum gain error (G = 1000)

     0.3 µV/°C maximum input offset drift

     0.5 nA maximum input bias current

  Wide supply range

     3.6 V to 36 V single supply

     ±1.8 V to ±18 V dual supply

  Input overvoltage protection: 40 V from opposite supply

  Gain range: 1 to 1000

APPLICATIONS

  Medical instrumentation

  Industrial process controls

  Strain gages

  Transducer interfaces

  Precision data acquisition systems

  Channel-isolated systems

  Portable instrumentation