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PCM5100: PCM5100 EMC In Pin 2/4/6/7

Fery Feng
Intellectual 2270 points
Part Number: PCM5100
Other Parts Discussed in Thread: PCM5102EVM-U

Hi team,

My customer is using PCM5100 in car audio. Recently they have test EMC noise in Pin 2/4, as show below, could I have you comments why they can see such EMC on Pin 2/4?


I upload the their PCB layout, could you share your advises to improve the layout, so as to improve the EMC performance?

  • 0
    TI__Guru 57800 points

    Hi, Fery,

    I can't see the schematic close to the pins with the issue, could you please re-upload the schematic?. Pins 2 and 4 are used as the terminals for the flying capacitor required for the charge pump. From the layout perspective, we recommend to use a single ground plane for both analog and digital grounds, we have seen previous issues where having separate grounds can cause problems for automotive applications. Having ground poured around the charge pump capacitor is also a good technique. 

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • 0 in reply to Diego Melendez
    TI__Intellectual 2270 points

    Hi Diego,

    Thanks for your reply! below is the complete SCH, please help to check it and share the ways to improve.

  • 0 in reply to Fery Feng
    TI__Guru 57800 points

    Hi, Fery,

    Thanks for the complete schematics. The circuit seems fine, so the issue is probably related to the layout of the part. As mentioned before, having a single ground plane for the device and pouring ground around the charge pump capacitor may help with this issue. 

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer

  • 0 in reply to Diego Melendez
    TI__Intellectual 2270 points
    Hi Diego Meléndez López,

    Could you share some layout guide line about this part or related application?

    Thank you.
  • 0 in reply to Fery Feng
    TI__Guru 57800 points

    Hi, Fery,

    In general we recommend to follow the layout guidelines from our EVM. Please refer to the PCM5102EVM-U User's guide where you can find the layout of the evaluation module. 

    Best Regards,

      -Diego Meléndez López
       Audio Applications Engineer