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TUSB4020BI: Console related problem and Hub recognition

Lacey Lin
Intellectual 2900 points
Part Number: TUSB4020BI

Hi team,

My customer use the TUSB4020BI as a USB Hub.

Below are the schematic.

6136.USB Hub.pdf

But there occurs two problem:

1. After initialization, the console port will continue printing below information.

2. Sometimes the USB Hub cannot be recognized.

Could you help to solve above two questions?

Thanks a lot!

Lacey

  • 0
    TI__Expert 7395 points
    Hello Lacey,

    Schematic looks good, although I would recommend to use stronger PU resistors (4.7K would be better) on the OVERCURx terminals (pin 5 and 8)

    I would also recommend to X-ray your board and verify soldering on the thermal pad is evenly distributed. We have seen similar issues when soldering is poorly done, since the thermal pad is the only ground terminal on the device.

    Finally, make sure the your implementation is following the power-up sequence defined on the datasheet at section 7.7. Since you are enabling VDD33 before VDD, then it is recommended to assert GRSTz low for at least 3ms after both power supplies are stable.

    Regards,
    Jorge