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  • TI Thinks Resolved

PCM2904: Device not recognized by PC/MAC

Part Number: PCM2904

We have a design lifted directly from the Datasheet using PCM2904 for stereo audio in/out. With the PCM2904 installed, neither WIN nor MAC OS recognize the presence of the CODEC. They don't acknowledge that anything is plugged into the USB at all. Simply swapping out the PCM2904 for the PCM2906 solves the problem with no other board or component changes.

The issue is that we have a reel of 2000 PCM2904's in stock, representing a considerable investment that the distributor does not want to take back, so we would like to use them up if possible. Is there perhaps something we may be doing wrong that is not obvious from the datasheet which would make the 2906 work but the 2904 not? Any ideas?

  • Hi, Bob,

    The PCM2904 is a device with known issues so we don't recommend using it  (please refer to this app note), the PCM2906C is a similar part with updates done to fix those issues. Even considering this, the PCM2904 should be recognized by the OS if the circuit is correct (which is assumed as PCM2906C is operating normally). Do you have a PCM2904 EVM that you can use to test your units?.

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

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