TUSB8041: TUSB8041IRGCR drop msg during 1000 times plug/unplug

Hi Sean:

    Can you rake waveform for 1.1v/3.3v/GRSTz signal?

   Can you provide schematic and layout for review?

   It could be power on sequence issue or USB3 signal integrity issue.

Regards

Brian

Hi Brian, 

Pls kindly see the schematic. 

Customer tested other 5G module , all pass. 

Only Telit FN990A28 see this problem. 

Pls kindly suggest if you experience the same at other customers side. Thanks a lot!

SIEE-CAI134_V0.2-頁面.pdf

Do you have AC caps on TX and RX signal?

Regards

brian

Brian Zhou said:

Do you have AC caps on TX and RX signal?

Hi Brian, 

Only on TX. Does it matter?

What's the function of the AC caps?

Thanks a lot!

Hi,

Having the AC caps on the TX is correct. The value of this cap should be between 100nF - 200nF.

The function of these AC caps is to set the common mode of the signaling to 0V. The capacitance of the bus is required to be between 75nF to 265nF per the USB3.x spec. 

The team is currently on leave due to US holidays. We will get back to you shortly. 
Thanks,

Vishesh

Hi Vishesh, 

Must RX put AC cap as well?

Thanks a lot!