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TUSB4020BI: USB HUB

Nicolo Baggiani
Prodigy 20 points
Part Number: TUSB4020BI

Hello Support

We have a question regarding the usb HUB TUSB4020B.

We have a fixed upstream port that is always active.

The upstream port of the HUB is connected to an  STM32H753IIT6 ST  microcontroller.

On pin 9  USB_VBUS  of the TUSB4020BI HUB  we have  a connection to a fix 5V voltage. 

We have following question:

What is the function of the input USB_BUS ?

It detect a voltage or a rising edge of the supply VBUS? 

Do you have a example schematic where the upstream port is not removable.

We want to be sure that the new pcb is correct and of this reason we need your support.

Best Regards

Nicolo Baggiani

HW Engineer

  • 0
    TI__Guru*** 146535 points

    USB_Vbus should be around 0.5v so you need voltage divider 90k/10k to Vbus

    USB_VBUS is a detection input and should only be high when an active host is connected. If this is an embedded design, but when the host is “disabled”  it leaves its receiver terminations enabled and USB_VBUS is high, the hub could enter compliance mode.