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