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TS3DV642: How to improve layout to resolve DisplayPort SI issue of HBR2/HBR3 Level and Equalization Verification Testing

Cho Lena
Prodigy 50 points
Part Number: TS3DV642

Tool/software:

Hi, Sir,

Our motherboard uses TI TS3DV642A0RUAR to switch DP signals from Raptor lake-U(SOC) and MXM module.

 

There are DP SI issues about HBR2/HBR3 Level and Equalization Verification Testing when we switch DP of Raptor lake-U. 

 

Because lengths of DP is not over Maximum length of Intel PDG. Those SI issues are likely not caused by signal attenuation.

Do you have any experience related to SI failure of HBR2/HBR3 Level and Equalization Verification Testing?

Could you provide any suggestions on how we can resolve this SI fail issue?

Do you have any recommendations for the length and number of vias from the TS3DV642A0RUAR to the DP connector?

  • 0
    TI__Guru**** 176811 points

    Hi,

    Can you please share the full compliance report including the measured waveform? 

    The TS3DV642 is a passive MUX and will not provide any tuning capability to these failed test items. You will have to tune the actual SWING and Pre-emphasis value associated with each level of Raptor lake-U(SOC) and MXM module in order to pass the test.

    Thanks

    David

  • 0
    Prodigy 50 points

    Hi, David,
    The full compliance report is below.
    Please provide suggestions that can let us to improve DP layout.
    Thanks.

    DP1 CTS1.4 SSC test report.rar

  • 0 in reply to Cho Lena
    TI__Guru**** 176811 points

    Hi,

    Looking at the report, the failure happens at HBR2 which will have higher insertion loss. So you have to tune the DP source SWING and Pre-emphasis setting associated with each level to pass the compliance test.

    For example, on this failure, the minimum spec is 5.104dB while the measured value is 5.0236dB. So you can bump up the 6dB setting a bit in order to pass the test.

    Thanks

    David

  • 0
    Prodigy 50 points

    Hi, David,
    Thank you for your kind assistance, we will try to set SWING and Pre-emphasis with intel GOP to retest SI.

    Could we add a redriver (between TS3DV642 and DP connector) to fix the failure due to insertion loss?

  • +1 in reply to Cho Lena
    TI__Guru**** 176811 points

    Hi,

    Yes, you could add a re-driver such as SN65DP141 or TDP142 to compensate the insertion loss between Intel Source and re-driver input as much as possible. With the re-driver providing the compensation, this will help preserve the Source Pre-emphasis as much as possible. 

    Please note with linear re-driver, you have to make sure the combined amplitude of source SWING and Pre-emphasis has to stay within the re-driver linearity range, otherwise the signal will be in the re-driver compression region and fail the SWING and Pre-emphasis test again, but for a different reason.

    Thanks

    David