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PCM5100: Synchronization of multiple audio DACs

Expert 1510 points
Part Number: PCM5100
Other Parts Discussed in Thread: , DAC8871, PCM1794A, DAC80501, PCM5122, PCM1690

Hello,

     Please advise if multiple PCM5100s can be made to work in phase i.e., the outputs are phase synchronous. Also, will there be any delay between the two audio outs of a single device?

Does this need any special way of connecting. 

We plan to feed an external SCK to each IC so that the internal PLL is bypassed. Would this be a better approach to achieve our target?

Look forward to your inputs,

Regards.

  • Hi SM,

    Having the multiple PCM5100A devices share an LRCK and SCK will keep the outputs in phase, assuming that the data source is also providing the data in phase. It is possible for the output to be out of phase due to initialization time, but it would not be expected to be more than ~50% of one sample time.

    Thanks,
    Paul
  • Hello Paul,
    Thank you for your response. May I ask you to please advise on the following:
    1) An alternate approach (multiple DAC outputs)
    2) Ensuring that the outputs are in phase every time (or at least be able to detect it through some register and then resetting or reprogramming the device).
    Regards,
  • Hi SM,

    We are not able to guarantee phase synchronization for multiple PCM5100 in a resolution less than one sample time (1/fS).

    You consider a device that allows for an external digital filter where you control the filter output (PCM1791, PCM1794A) or you can consider a precision DAC, but that might depend on your application (DAC8871, DAC80501).

    thanks,
    Paul
  • Hello Paul,

                Thank you for the input. I forgot to mention I need a sampling rate of at least 250Ksps. Which device could I go for in this case?

    Regards,

  • Hi SM,

    The PCM1794A and PCM1791 can support 250ksps in external filter mode. The DAC8871 and DAC80501 can also support that rate. The PCM5100 does not support that rate, but the PCM5122 could with the clock tree being configured manually.

    Thanks,
    Paul
  • Hello Paul,

                Thanks a lot. To summarize, multiple PCM1794A can be made to work synchronously or in other words the outputs will be in phase. 

                 Is there a audio codec  from TI that we can use that will ensure sample level synchronization?

    Regards,

  • Hello Paul,
    Can we use the PCM1690 to achieve phase synchronous outputs.
    Regards,
  • Yes, the PCM1690 will be synchronized, but it is also limited to 192ksps input.