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TUSB211: pre-channel and post-channel design cehck

Kai Lai
Genius 9861 points

Part Number: TUSB211
Other Parts Discussed in Thread: TUSB216, TUSB216-Q1

Hi Team,

Here is a design scenario,

PCH to MB 5 inch > Cable 7 inch > daughter board 2 inch

Do you think TUSB211 have capability can support here?

Will suggest customer put TUSB211 at MB side or daughter board side ? 

Is there any Maximum VIA quantity suggestion with pre-channel and post-channel?

Is there any Maximum distance (inch) with pre-channel and post-channel?

My understanding is we will not provide a "distance" and will let customer estimate the total signal lost right? How is our TUSB211 &TUSB216 redrive capability (in dB)?

Thank you!!

Kai

  • +1
    TI__Guru 60870 points

    Hi Kai,

    Is the device located on the daughterboard?  If so, this is a very short trace and a redriver may not be needed.  If they want to add an option for it, it should placed on the MB near the cable connection.

    If there is just an exposed connector on the daughterboard, then the redriver should be placed on the daughterboard.

    We do not have a maximum via quantity, but in general they should be minimized as much as possible and matched between the DP and DM lines.

    Due to the nature of our USB 2 redriver solution there is no specific insertion loss (in dB) that accurately corresponds to a particular boost setting of the device. Please find the rough estimates below for AC boost provided by TUSB216-Q1. These numbers are based on eye diagrams in the datasheet and are all typical values.


    AC Boost at 240MHz (typ)
    Boost 0: 3.0 dB
    Boost 1: 3.5 dB
    Boost 2: 4.7 dB
    Boost 3: 5.2 dB

    Regards,

    JMMN

  • 0 in reply to JMMN
    TI__Genius 9861 points

    Got it!

     Thanks for your reply!!

  • 0 in reply to Kai Lai
    TI__Genius 9861 points

    Hi ,

    If customer use TUSB216 do you think it is OK to put redriver at mother board side ?

    Since I'm concern that TUSB211 redrive capacity, so I promote TUSB216 here.

    Mother board { PCH -->5 inch trace --> TUSB216 --> connector } --> high speed cable(3dB loss) --> connector --> daughter board with Type-A connector can plug in device.

    Since space limit with daughter board, customer prefer our redriver put at mother board, do you see any risk ?

    Thanks!

    Kai

  • +1 in reply to Kai Lai
    TI__Guru 60870 points

    Hi Kai,

    They should try to place the redriver away from the PCH as much as possible in the motherboard layout.   Also, the TUSB216/I should be set to BOOST 0 in initial evaluation to prevent overdriving signals and then move up from there if additional boosting is needed.

    Regards,

    JMMN