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TUSB8041: TUSB8041 problem consultation

Vayne Li
Expert 1600 points

Part Number: TUSB8041
Other Parts Discussed in Thread: TPS2561

Hi Teams,

My customer has a project where they used TUSB8041+TPS2561 for a HUB application. Occasionally, when the device is powered on, the PWREN output of 8041 is not pulled high, resulting in the VBUS of the downstream port running out of power.

image.png

image.png

This is a testing device, and the feedback from end customers was initially positive. However, this issue occasionally occurred while using it. At first, they thought it was ESD causing damage to the VBUS switch, but after replacing the chip with ABA, they found that the function was normal. Then they suspected the current limiting protection again, and checked that the fault pin on the dead side was not pulled down, it was the PWREN of the HUB that was not pulled up.

The following is the waveform of the test. Blue represents VDD 1.1, yellow represents fault, and purple represents PWREN.

image.png

After being powered on for about 4 seconds, PWREN pulled down.

Please help analyze the cause of the problem and provide some suggestions. Thank you~

 

  • 0
    Expert 1600 points

    Hi Teams,

    I will update the status on my end. Currently, the hub RST timing does not meet the manual requirements. I tried manually lowering the RST to solve the problem, and asked their colleagues in the underlying software to make the necessary changes.

    Because the problem occurred only after long-term use, may the timing not meet the requirements and cause internal damage to the 8041 chip?

  • 0 in reply to Vayne Li
    TI__Guru**** 155665 points

    Hi Vayne:

      What status of PU or PD for pin 40/41/42?

     Can you change Cap to 1uf on GRSTz pin?

    Best

    Brian