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AD5293 variable gain amplifier

Question asked by Unai on Sep 12, 2013
Latest reply on Sep 13, 2013 by musach

hello,

I am using the AD5293 (100K) digital potentiometer along with the AD8675 Op amp. I want to have a variable gain, to amplify the output of a tranformers.

 

variable gain circuit.JPG

+Van= +11.2V

-Van= -11.2V

The input signal is 50Hz.

 

I set the gain to 128, programming D=1016, and i calibrate my circuit. Everything fine till here. But then, there is a drift in the error. It takes more than 20 minutes to be stable, but not enough stable. If i use a resistors it doesnt happen.

 

Regards,
Unai Goyarrola

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