TUSB4041I: Problem getting all 4 Downstream ports functioning

Sam Deghuee

Part Number: TUSB4041I

Hello,

We are using this part but have only gotten two of the downstream ports to recognize any USB devices. Right now Downstream port 1 and 4 are functional while 2 and 3 are non responsive. The upstream port has no problem and the device is recognized every time I plug it in. I have checked the continuity of the data signals and power. The design can be found at this github. I'm not sure what to check next to make this design functional any advice would be helpful.

Thanks,
Sam Deghuee

over 7 years ago

0 Michael.Walker over 7 years ago

TI__Mastermind 19720 points

Can you please post a picture of the Schematic?

0 Sam Deghuee over 7 years ago in reply to Michael.Walker

Prodigy 45 points

Here are the images exported from Eagle for the Schematic and the board.

Thanks for quick response,

Sam Deghuee

0 Michael.Walker over 7 years ago in reply to Sam Deghuee

TI__Mastermind 19720 points

Can you measure the voltage on VBUS when multiple devices are plugged in to see if the 5 V drops any? also can you make sure that the thermal pad is properly grounded?

0 Sam Deghuee over 7 years ago in reply to Michael.Walker

Prodigy 45 points

The VBUS is a steady +5V, testing was done with one port at a time. Unfortunately there are no vias underneath the chip to fully verify the grounding, however we are fairly certain it has a good solder connection, especially as the other ports are functional.

0 Michael.Walker over 7 years ago in reply to Sam Deghuee

TI__Mastermind 19720 points

Have you done testing with more than one device plugged in at a time? Can you post a high quality picture of the layout?

0 Sam Deghuee over 7 years ago in reply to Michael.Walker

Prodigy 45 points

Not explicitly, I can do that do you have an idea of what useful information could be gained in doing that? Here is a 1000dpi exported board image, if you need higher quality let me know.

0 Michael.Walker over 7 years ago in reply to Sam Deghuee

TI__Mastermind 19720 points

The issue that I can see with your board right now is that you have a very weak connection to GND. The GND of the device is only connected by one trace and the solder connection to the GND pad might not be that good either. This might be causing your issue with the only two ports working. One of the ways you can test this is to press down on top of the chip when using the chip this might give the chip a better connection to the GND pad. The other way to test is to fix your board design using the file that I will send you as a guide.

"I can do that do you have an idea of what useful information could be gained in doing that?"
It can help me narrow why only two ports are working. The more information that you give me the easier it is to debug your problem.

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TUSB4041I: Problem getting all 4 Downstream ports functioning