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[TPS2549-Q1, TPS254900-Q1] USB test compliance of High-Speed System (Host)

Akihisa Tamazaki
Genius 12440 points
Other Parts Discussed in Thread: TPS2549-Q1, TPS2546-Q1, TPS254900-Q1

Hello team

The customer has a question about  USB test compliance of High-Speed System Test Requirements.

Have you ever seen that some customers had passed the USB test compliance of High-Speed System when they used TPS2549-Q1, TPS254900-Q1, not used redriver?  The customer mentioned that he evaluated TPS2546-Q1 before, then he suffered from the eye pattern of High speed signal (D+/D-)., as the result  he gave up using TPS2546-Q1. He would like to confrim TI already has seen some customers got USB logo when TPS2549-Q1 and TPA254900-Q1 was used, although he understood that eye pattern which TI measured was written in the datasheet of TPS2549-Q1 and TPS254900-Q1.

Would  you please advise?

Best Regards,

Akihisa Tamazaki

  • 0
    TI__Guru 50090 points
    HI Tamazaki-san,

    Let me confirm what we can share with the team. My understanding is both devices can get USB logo with both devices.

    Regards,
  • 0 in reply to JCHK
    TI__Guru 50090 points

    HI Tamazaki-san,

    I am re-posting Tina-san's reply so others can see:

    'Yes, we have customers passed the USB test compliance of High-Speed System when they used TPS2549-Q1, TPS254900-Q1 without redriver.

    However, it will be hard to guarantee that TPS2549-Q1, TPS254900-Q1 will pass the compliance test without redriver in Mitsumi’s system, before knowing their system environment.

    Because USB-IF certification test is a system level and below two key factors are needed to be considered which will have big impact on the eye diagram:

    1. PCB trace length between USB host and TPS2549-Q1/254900-Q1, and PCB trace length between TPS2549-Q1/254900-Q1 and USB connector;

    2. Cable length and impedance; If cable is very long, the source(USB host) eye diagram will pass marginal or even fail without any device along the data lines (no TPS2549-Q1/254900-Q1). Also good quality cables and bad quality cables have difference.'

    Please let me know if this is what you were looking for.

     

  • 0 in reply to JCHK
    TI__Genius 12440 points
    Hello John-san,

    Thank you for your answer. I understood.

    Best Regards,
    Akihisa Tamazaki