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ADAU1961 Internal Input Biasing

Question asked by awjennin on Jan 16, 2018
Latest reply on Feb 9, 2018 by DaveThib

Hello,

 

We are utilizing the ADAU1961 in a design and when taking some design-verification measurements I'm not seeing any bias-voltage applied to the inverting inputs (LINN, RINN),  while the non-inverting inputs (LINP, RINP) both are biased at AVDD/2 per what I expected from the datasheet.

 

I have isolated the test setup. Currently it includes the ADAU1961 installed on a circuit card, but the series DC-blocking caps (10uF) have been removed. I am probing right at the ADAU1961 pins 10-13. The microprocessor that interfaces to the CODECs I2C/I2S interface is on a daughtercard, and this card has been removed from the system.

 

Thanks

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