ADAU1961 ADC Offset

I have an AC coupled audio signal going into the pseudo differential input on the ADAU1961 but on the output of the ADC there is a 'DC' offset in the ADC Data. Is this normal? I'm sampling at 16 Bits 16KHz

I've attached a file with captured samples

data.csv.zip
  • 0
    •  Analog Employees 
    on Sep 30, 2014 6:54 PM

    Hello Oliver,

    Yes, it is normal for an ADC to have a small DC offset. I recommend you turn on the HPF,(High Pass Filter), on the output of the ADC. This will not affect the audio since the cutoff is 2 HZ and you are cap coupling the input signal already. The register that holds this bit is R19:ADC_CONTROL, and it is at address 0x4019 and bit 5 is the high pass filter.

    Thanks,

    Dave T