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TUSB542: USB SuperSpeed data lines lane inversion

Part Number: TUSB542
Other Parts Discussed in Thread: , TUSB321

Tool/software:

Hi TI team,

I'm seeing conflicting data on threads in the forum posts regarding the swapped polarities in regards to the SuperSpeed data lines and just want confirmation that my implementation is correct. In the TUSB542 datasheet as well as the TUSB542EVM schematic, some of the polarities are reversed as shown below:

I know there's a name discrepancy on the datasheet pin names and the evaluation board schematic but I believe I got passed that.

Here's a snippet of my schematic. Is there any issue on the way my connections are tied?

It is my understanding that the lane inversion of USB 3.1 devices should handle this issue but want to make sure the TUSB542 does as well. 

Regards,

  • Hi Roland,

    Since USB3 supports polarity swapping it is ok to swap the p/n lines on either side of the TUSB542. There is no issue doing so.

    1. Are these the same net? Its important to make sure the VBUS_DET pin on the TUSB321 is pulled up to the Type-C VBUS.

    2. I don't see any ESD protection in your schematic. Its a good idea to keep an ESD diode between the TUSB542 and the Type-C receptacle to protect our device from ESD strikes. A device we typically recommend is the PUSB3FR4.

    Best,

    Shane 

  • Thanks for the timely response Shane and your answer is exactly the confirmation I needed. Note that this was just a snippet of the full circuitry. The VBUS voltage is indeed the same +5V from the Type-C connector but just filtered and I do utilize ESD protection (ESD8006MUTAG).