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TUSB8020B: Input voltage on VBUS pin etc.

Motoyasu Hattori
Genius 12480 points

Part Number: TUSB8020B

Hi,

I have two questions of TUSB8020B

  • Pull-up resister value on SMBUSz/SS_DN2 pin
    If TUSB8020B uses I2C mode, please let us know the pull-up resister value on SMBUSz/SS_DN2?

  • Input voltage on VBUS pin
    Could you please let us know VIH on VBUS voltage and VIL on VBUS voltage?
    My customer does not need VBUS detection, because he connects TUSB8020B with USB port of CPU on same board.  So he plans to use VBUS pin as USB reset.   Datasheet said VBUS operating voltage is 0 - 1.155V, but has not described "input minimum voltage which VBUS recognizes high" and input max voltage which VBUS recognizes Low".   Please advise us.

Thanks and best regards,
M.HATTORI

  • 0
    TI__Guru 60870 points

    Hello M. Hattori,

    Answers in-line below:

    • Pull-up resister value on SMBUSz/SS_DN2 pin
      If TUSB8020B uses I2C mode, please let us know the pull-up resister value on SMBUSz/SS_DN2?
    • [JMMN]  Internal pullup resistor is 150 uA (22K) nominal and 225 uA (14.6K) maximum.
    • Input voltage on VBUS pin
      Could you please let us know VIH on VBUS voltage and VIL on VBUS voltage?
      My customer does not need VBUS detection, because he connects TUSB8020B with USB port of CPU on same board.  So he plans to use VBUS pin as USB reset.   Datasheet said VBUS operating voltage is 0 - 1.155V, but has not described "input minimum voltage which VBUS recognizes high" and input max voltage which VBUS recognizes Low".   Please advise us.
    • [JMMN]  Vih(min) = 400 mV, Vih(max)=1.155V.  The hub only detects when the USB_VBUS is high, it doesn't check for a low input.

    Regards,

    JMMN