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TUSB1210: Questions about PCBLAYOUT of TUSB1210

SHENG YANG
Expert 1350 points
Part Number: TUSB1210


HI,Team.

As shown on the left side of the figure below, it is the signal arrangement of the USB ULPI interface on a connector. The pin spacing of the connector is 0.5mm. I want to eliminate a few GND pins because the connector has insufficient pins. Pin 18 is a USB power supply overcurrent detection signal, which is an open-drain signal connected to the GPIO. Pin 17 is the reset signal of USB_PHY. Can the signal arrangement be operated according to the arrangement on the right?Thank you so much.

As shown below is the LAYOUT diagram of TUSB1210. The first pin of the IC is the pin in the red box in the picture? The definition of 8, 15, 16, 24, and 25 of this chip is NC. Why are they all wired in the picture? Thank you so much.

  • 0
    TI__Guru*** 148115 points

    Hi Sheng:

         I prefer to move reset and OC below CLOCK and GND

        Regarding NC pins, I didn't see any reason why to wire those pins, You can just leave it unconnected on PCB.

    Regards

    Brian

  • 0 in reply to Brian Zhou
    Expert 1350 points

    Hi Brian

    thank you for your reply.

    My statement may be ambiguous, the NC pin is not a useless pin, I need to connect other signals. So the current PIN pin is not enough. I will arrange the signals as suggested in your reply. According to your reply, the GND of pin 10 can be canceled. Is your reply supported by design references or use cases?
    Does TI have any technical documentation on this? ULPI signal routing requirements. thank you.

  • +1 in reply to SHENG YANG
    TI__Guru*** 148115 points

    Hi Sheng:

       If I understand correctly, you want to adding more NC pin on connector and sacrifice Other pins like GND pin? 

    If Yes, then I will disagree. I prefer adding more GND pin than useless NC pin.

      This is real layout connection, the connection on all 4 sides are same. the original layout designer just find a easy way for layout for this small board.

    They connected all the pins to big vias first even before they know the names of the pins , either NC or not.

       There is design guide for ULPI in datasheet on page 61. 

    Regards

    brian

       

  • 0 in reply to Brian Zhou
    Expert 1350 points

    Hi Brian

    thank you for your reply.

    The USB signal will be connected to a connector, the connector pin is not enough, the connector pin spacing is 0.5mm. I want to meet the premise of 3W cable spacing USB signal as little as possible to occupy the connector pin.There are other signals that need to be connected to the connector. There is no NC pin.

    I will reserve enough line width when wiring on PCB. What matters now is the pin assignment on the connector. Because the pin spacing of the connector is 0.5mm, this cannot be changed.

  • 0 in reply to SHENG YANG
    TI__Guru*** 148115 points

    I got it,

    Regards

    Brian