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Original question:

DS125BR820: Recommend the Configuration for using JESD204B Repeater.

DS125BR820: Why Recommended the Output voltage setting Level 3?

Louis Han15
Genius 4680 points
Part Number: DS125BR820

hello

You had recommended the Parameter setting value like below link.

https://e2e.ti.com/support/interface/f/138/p/662912/2439581

but My customer is ask the below.

 

About the VOD/VID ratio, the RX mask Results improved with VOD/VID = 1.0 Setting but I'll ask a more detailed response from TI that why they recommend

VOD/VID = 0.77 setting, So no need for additional component changes.

Regards.

  • 0
    TI__Mastermind 43795 points
    Hi Louis,

    There are a lot of system variables beyond the DS125BR820 which control the final RX mask results. The lower VOD/VID setting can have a positive effect on some applications. As long as the higher VOD/VID setting is giving consistent results there is no problem to use it in your application.

    Regards,
    Lee
  • 0 in reply to Lee Sledjeski
    Genius 4680 points

    Hi Lee

    Thanks for your support.

    Do you have a back data or reference for recommend the Output voltage setting to level 3?

    Regards.

  • 0 in reply to Louis Han15
    TI__Mastermind 43795 points

    Hi Louis,

    I have found that setting the voltage level to ~ 3 gives a very good transfer of the lower frequency waveform data.  This helps to ensure the system receiver is getting an accurate representation of the original transmitted signal.  The graphic below shows a set ofTx signals on the left and the corresponding output signals of the DS125BR820 on the right.

    Regards,

    Lee

  • 0 in reply to Lee Sledjeski
    Genius 4680 points

    Hi Lee

    I requested the Output Voltage Settings for JESD204B running at 9.8 Gbps.

    Is it JESD204B low frequency waveform data?
    Is the VOD setting level specified according to the frequency range used?
    What are the five waveforms of the attached files?
    Regards.
  • 0 in reply to Louis Han15
    TI__Mastermind 43795 points

    Hi Louis,

    JESD204B should be okay with the settings I recommended.

    The VOD setting for JESD204B is not as critical since the interface does not use link training.

    The signals in the attachment are from bench equipment, they are just a repeating clock pattern with a 1.0V peak to peak amplitude.  The signals each have a different de-emphasis level.  The DS125BR820 is showing how it can accurately replicate each of these levels.

    Regards,

    Lee