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ADAU1701 Aux_ADC input circuit.

Question asked by leonxp on Feb 5, 2013
Latest reply on Feb 19, 2013 by leonxp

Hi everybody. I've got an ADAU1701, I'd like to use one of auxiliary ADC through MP pins. I read from Datasheet about input circuit to ADC Sigma-Delta but nothing about Aux ADC. Known specifications about Aux ADC full-scale input. Aux-ADC input circuit I realized, has been built with a capcitor and a resistance. Input wave is a 1KHz, 0.5 Vrms sinusoid, but the output wave I get is very damaged.

 

See the picture attached.

 

20130205-152125.bmp

 

The red wave is DAC out, the blue wave is the Aux_ADC input.

 

 

Maybe the input circuit is bad or maybe the low Aux_ADC resolution originates this behavior. I'd like to know why.

Does anybody know how to make an efficient Aux ADC input circuit?

Thanks to all,

regards.

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