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TUSB2046B Hardware Question

tbriseb
Intellectual 355 points
Other Parts Discussed in Thread: TUSB2046B

Hi there,

I have a few questions regarding the TUSB2046B device.

1) Is the 33 Ohm series termination resistors and 1.5K pull up resister required if the hub is embedded on the PCB.  Meaning, that is never detached from the processor host port.  Copper on the PCB has been routed as 90 Ohm diff pair, no cabling.

2)  Is the TUSB2046 capable of enabling/disabling the /POWERON signal from an upstream port?  Or is the /OVRCURRENT input the only option?

3)  Looking at the 2.0 compliance checklist, there is a section 4.2 Bus Power and subsection BP2 requests:  Does the hub allow host controlled power switching of its downstream ports?

Look forward to any feedback you are able to provide us.

Thanks

tB

  • 0
    TI__Guru* 76130 points

    Hello,

    For your question 1) : If you are assuring 90ohm differential impedance then you don't need the 33ohm series resistor. The 1.5K pull-up is required to "set" the speed whether you place it on D+ or D- (full/low).

    For your question 2) and 3) I'am afraid I don't quite understand you.

    The hub will assert the /PWRON signal when its /OVRCUR is asserted. The USB host communicates with the hub to determine when to clear de /PWRON signal.

    Regards.