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ADA4700 - DAC-controlled dual polarity voltage source

Question asked by K1MGY on Mar 7, 2016
Latest reply on Apr 11, 2016 by JinoL

I've selected the ADA4700-1 in an application to drive a static charge upon a stainless steel plate (conductivity measuring instrument).  For this purpose I have two supply rails, one at +38V and the other at -38V.   The ADA4700-1 will be configured as an inverting gain stage.  There is virtually no current load on the output.

 

I'd like to drive the ADA4700-1 from a microprocessor's DAC output (0 to 3.3v) such that the ADA4700-1 presents +38V when the DAC drive is 0 (or +3.3) and -38V when the DAC drive goes the other way.

 

To make this work, I think we need to swing the DAC drive above and below 0V.  Is there any way to avoid this conversion through biasing the ADA4700-1?

 

Suggestions on the best way to achieve our desired result most gratefully appreciated.

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