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Ground loop breaking

Question asked by @jt on Apr 9, 2015
Latest reply on Apr 13, 2015 by ColemanR

My circuit is USB-powered, has a microcontroller and a ADAU1361 codec.

When connecting the audio input or output of the codec to the same computer as where it is powered from, ground loop noises appear. The solution is inserting a resistor between the audio jack I/O ground and the supply ground, and referring the audio signals to the audio jack ground.

My question is how to deal with this with the ADAU1361 codec. Is it possible to insert a 5 ohm resistance between analog and digital ground? The datasheet only discusses a single ground for both. Or is it possible to capacitively reference CM to the jack I/O grounds rather than analog ground?

 

Thanks!

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