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  • TI Thinks Resolved

AM5728: DSS EMC issue

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Replies: 4

Views: 287

Part Number: AM5728

I'm using an AM5728 coupled with a DS90C387 to interface to a display and am having some radiated EMC issues. There are likely a couple of causes from layout to cabling, however I'm hoping that we might be able to reduce the emissions from the PCBA by turning down the drive strength on the VOUT pins as the traces are really short and there seems to be some over/undershoot on the clock and signal pins. In addition, I'm wondering if the display clock can be made into a spread-spectrum clock to reduce our narrowband emissions.

I can probably accomplish similar things by doing some schematic / layout changes but those are expensive and I'd love to try them out by tweaking register settings first. Any help is appreciated!

  • It's not possible to control the I/O drive strength on this device. A possible solution is to place serial resistors on the signal lines.

     

    Best Regards
    Biser
  • In reply to Biser Gatchev-XID:

    Hi Biser,

    Regarding the second half of this question, is it possible to use a spread spectrum clock for this display interface?

    Thanks,
    Brian Angiel
  • In reply to Brian Angiel:

    Brian,

    Based on my review of the AM5728 TRM, we do not support SSC clocking on any of the PLLs related to the DSS.  I am double checking this information.

    Tom

     

  • In reply to Tom Johnson 16214:

    Brian,

    I received additional confirmation that SSC clocking is not supported on any of the PLLs related to the DSS in AM572x devices.

    Tom

     

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