Connect microphones to ADAU1979

In the SC584-EZLite there are ADAU1977 & ADAU1979.

I would like to connect 8 microphones to the EZLite, 4 to each codec.

However, the ADAU1979 doesn'y have mic bias as ADAU1977.

How can I still use standard microphoens with the ADAU1979?

In other words, how do I bias micro[phones with the ADAU1979?

Thanks

Alon

  • Hello Alon,

    The ADAU1979 does not have any PGA to amplify microphone level signals. That is why it does not have a MicBias output. So you will need to use an external pre-amp or a different ADC/Codec and bring in those signals onto the board.

    Dave T

  • what do you mean by 'standard' microphone ?

    if it means dynamic mic, you don't need power to mic

    if anything else, power supply circuit should be designed outside ADC

    with anything, the preamp is needed that amplify audio signal from mic by 100 ~ 1000 times

    you can use SSM2019 and refer to the datasheet.

    if you want to use ceramic microphone, refer to the phantom power circuit in the datasheet.

    you may revise the protect circuit against EMC or 48V level power switching...

    jeremy.