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TUSB8041: Connected to TUSB804 after signal loss occurs through HD3SS3415

Part Number: TUSB8041
Other Parts Discussed in Thread: HD3SS3415, HD3SS212

Hi,

I'm considering TUSB8041. Wehn I look at the datasheet, the output waveforms are listed in 9.2.1.3 Application Curves. On the contrary, is there any waveform information that can be accepted in the input section?

TUSB8041 is connected after signal loss occurs through HD3SS3415. I would like to check whether I can receive signals without problems with TUSB8041.

Thanks,

Conor

  • Hi Connor:

         As long as the input signal  still can pass the eye mask, TUSB8041 should able to receive the signal without any issue.

    Regards

    Brian

  • Hi Brian,

    There is no information on the horizontal axis of the waveform, etc. Where is the source of this waveform?
    If you have any reference material, please let me know.

    Thanks,

    Conor

  • Hi Conor:

       This is the eye mask  for transmitter defined in USB3.1 specification. There is no eye mask defined for receiver. But if your signal can pass TX eye mask, There  should be no issue for RX side to work.

        Another way to see if hub will work or not is to get trace length information on PCB between USB host to mux 3415 and trace length between 3415 to hub, so based on trace loss information, we will know if hbu will work or not.

     

    Regards

    Brian

  • Hi Brian,

    Another way to see if hub will work or not is to get trace length information on PCB between USB host to mux 3415 and trace length between 3415 to hub, so based on trace loss information, we will know if hbu will work or not.

    Also, after calculating the trace length from the USB host to the HD3SS3415 on the PCB and from the HD3SS3415 to the hub, how should I verify it? I didn't quite understand how to read the table you attached. It would be very helpful if you could explain it in detail.

    Thanks,

    Conor

  • Hi Conor:

      The trace length theory has nothing to do with table above. The eye mask just means if your transmitter has to pass eye mask  to make sure system works.

    This picture illustrate the system loss budgets for the USB 3.1 specification. The Gen 1 loss budgets allow for a maximum of 20dB loss, but have different budgets for each type of USB connector.

       Since there is no USB connector or cable in your system, so there is total 20db loss allowed between host to hub.

    If you have trace length loss between host to mux L1 and mux to hub L2, plus mux insertion loss at 2.5Ghz, if the total loss < 20db, your system should work.

    Regards

    Brian

  • Hi Brian,

    Thank you for the document. It will be helpful.
    Is there any documentation that talks about DisplayPort instead of USB? I am considering whether it is possible to switch similarly using HD3SS212. If you have similar reference materials, please share them.

    Thanks,

    Conor

  • Hi Conor:

         For display port, there is no such loss information. you have to pass eye diagram test at TP3 to guarantee receiver can work. This is eye diagram mask at TP3.

    Regards

    Brian