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TUSB1002A: Schematic Check - Implementation Check

Cameron Bolton
Prodigy 41 points
Part Number: TUSB1002A

Hi TI,

We're using the TUSB1002A (TUSB1002AIRGET) in a design and would like to verify our implementation of the redriver chip is correct.

The goal of the design is to allow Superspeed or superspeedplus signals (5Gb/s or 10Gb/s) to pass from the Host (via USB3 Type-B Receptacle) through the TUSB1002A redriver and then onto a USB3 Type-C Receptacle. 

We are using two TUSB1002A because we would like to pass superspeed or superspeedplus signals to both channels/sides of the USB Type-C receptacle. 

Mainly, I'd like to verify that the TUSB1002A will work with Type-B and Type-C receptacles (most application notes/examples have Type-A on both sides of the redriver). 

Also, do the Superspeed signals look like they are oriented correctly?

In the TUSB1002A schematic checklist, it states the following:

In our implementation, we are connecting the redriver to USB receptacles so we may have the superspeed signals reversed (i.e. SSTX of the host connected to SSRX input of the redriver). 

Do you see any issues with our implementation of the TUSB1002A? 

Sincerely,

Cameron Bolton

TUSB1002A Schematic Checklist.pdf 9513_RevA - Schematic.pdf

  • 0
    TI__Guru 64326 points

    Hi Cameron,

    Before I review schematic I would like to ask some questions. You are using external USB cables from the USB Host correct? Are you try to achieve a USB 3.2 x2 application? This kind of application is not allowed, you cannot connect two separate ports on the same USB-C connector.  Does your host support USB 3.2 x2 operation?

  • 0 in reply to Malik Barton57
    Prodigy 41 points

    Hi Malik,

    That's correct, we are using external USB cables from the USB host.

    The host supports USB 3.2 x2 operation but that is actually not the issue we're having trouble with. We should theoretically be able to pass a single lane of superspeed (5.0 Gb/s) traffic through to one side of the Type-C receptacle (with the second lane's TUSB1002A redriver disabled). However, we don't see any superspeed signals on any pin of the Type-C receptacle when a host is connected to J1 (first lane's type-B receptacle). 

    I think this is because the host side of the redriver has its superspeed signals reversed (TX of the type-b connector to RX of the redriver / RX of the type-b connector to TX of the redriver), but I'm not sure and that's what I'd like TI to verify. The Schematic checklist seems to indicate TX of the connector should be connected to TX of the redriver and RX of the connector connected to RX of the redriver. Is that correct?

    Regards,

    Cameron Bolton

  • +1 in reply to Cameron Bolton
    TI__Guru 64326 points

    Hi Cameron,

    Interesting, hosts that support USB 3.2 x2 should route signals to the same USB-C connector (On a prebuilt platforms). FYI, We will have a single chip solution for this application releasing early next year. Checklist is correct and it does look like you have TX and RX swapped on your current board. Type-B connector pins are defined from device perspective so there is no need to swap lanes again. I do recommend AC coupling TX with 220nF and RX with 330 nF on both sides of TUSB1002A.