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AD5206 wiper position problems

Question asked by MEGuy on Feb 8, 2017
Latest reply on Feb 22, 2017 by MEGuy

Hello,

I am currently designing a PCB so that I can take a single 40kHz input signal and by using two AD5206 100kOhm digital potentiometers, have four output signals which I can phase shift and magnify. The issue I'm running into is this: not all of the wiper positions give a clean output signal when varying my magnification. The phase shifting works fine. To change the magnification, I change the wiper position and therefor the magnification resistance. About 30% of the wiper positions work fine, they magnify the signal exactly how I want, but then other wiper positions just plain do not work, they induce a ridiculous amount of distortion into my signal.

 

One thing that makes this problem especially odd is that I had initially been using AD5206 100kOhm digital pots with a DIP footprint on my PCB design and it worked fantastically. It seems as though many distributors of that footprint have stopped selling it so I switched my design to use the AD5206 100kOhm digital pots with a SOIC footprint, this is when my problems started.

 

Because the other AD5206 DIP footprint worked, I think that my serial communication is fine, and my power input meets all the specs on the data sheet.

 

Has anyone else ever experienced a problem like this?

 

Thanks

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