Can I replace AD620 or AD8221 directly with AD8422 in my circuit?

Document created by analog-archivist Employee on Feb 23, 2016
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Can I replace AD620 or AD8221 directly with AD8422 in my circuit?

 

AD8422 is only available in the High-Performance Pinout which was introduced by
the AD8221, so a board layout change is required to switch from AD620 to
AD8422. AD8422 is pin-to-pin equivalent to AD8221, however it does have a
different gain equation, so the value of the Rg resistor must be adjusted.

The AD8221 and AD620 gain equation is: G = 1 +  (49.4 kΩ)/R_G
The AD8422 gain equation is: G = 1 +  (19.8 kΩ)/R_G

To put it another way, multiply your AD8221 or AD620 gain resistor value by
0.4008 in order to achieve the same gain with AD8422.

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