• State Resolved
  • Locked Locked
  • Replies 2 replies
  • Subscribers 33 subscribers
  • Views 941 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TPS65982 / alternate mode of DisplayPort

K.Yaita
Guru 29720 points
Other Parts Discussed in Thread: TPS65982, TPS65982-EVM, HD3SS460

Hi Team,

My customer considers to multiplex AUX_N/P signals to the SBU_1/2 pins for alternate mode of DisplayPort.
I would like to know if I should set AC coupling caps and pull-down/up resistors between USB TypeC connector and TPS65982.

It seems there aren't caps and pull-down/up resistors between USB TypeC connector and TPS65982 in TPS65982-EVM,
So I believe they aren't necessary but would like to confirm just in case.
http://www.tij.co.jp/jp/lit/ug/slvuaf8c/slvuaf8c.pdf

Best Regards,
Yaita

  • 0
    TI__Mastermind 30310 points

    Yaita-san,

    The TPS65982 is a companion chip to Intel's Alpine Ridge IC in the most common application using the High-Speed Mux for SBU1/2 pins for DisplayPort and ThunderBolt.

    Since the Alpine Ridge chip takes care of a lot of passive requirements internally, and the High-Speed mux is not routed to another IC on the TPS65982-EVM, it is not necessarily 100% accurate as a reference design for High-Speed & SuperSpeed routing, passive components, and terminations.

    In many non-ThunderBolt applications that still need DisplayPort support, the HD3SS460 is used as a companion chip to the TPS65982.

    It is optional to use the SBU1/2 Mux in the TPS65982 or the HD3SS460, but I recommend you follow the suggested application in the HD3SS460 as a guide for High-Speed and SuperSpeed passive components and terminations.

    For example, they do show pull-downs on SBU1 & SBU2:

    It is always easier to not populate resistors if they aren't necessary than to add resistors if they're needed but the pads don't exist on the PCB.

  • 0 in reply to Brian Berner
    Guru 29720 points

    Hi Brian-san,

    Thank you for your reply.
    Yes, my customer also considers to use HD3SS460 for SS Mux.

    Does the background of pull-down on SBUx recommendation come from Table 5-1 (page.187) in USB Type-C Specification 1.2?
    It seems SSTX and SSRX should be added pull-down resistor..

    Best Regards,
    Yaita