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DS90UB936-Q1: no output of external crystal

Betty Guo
Expert 7300 points
Part Number: DS90UB936-Q1

Hi team,

customer use 936&935 in two project, one is 4 lane mipi and one is 2lane mipi. the problem is for 4lane case, 936 work is normal while in the 2lane, the external crystal is no output, awalys is 1V.

below is 4-lane and 2-lane schematic, could you help to check it ? the 4-lane external crystal is the same with 2-lane. thanks.

936.zip

  • 0
    TI__Expert 5480 points

    Hi Betty, 

    I don't quite understand what you're asking. When you are using the 4lane configuration are you saying that the refclk is working good, but in the 2lane configuration the refclk is stuck at 1V?

    Thanks 
    Sally

  • 0 in reply to Sally Cheung95
    TI__Expert 7300 points

    Hi Sally

    yes, there have two UB936 on customer boards, one is 4-lane and one is 2-lane. for 4-lane, it can work properly, but for the 2-lane, they found no clcok. I attached customer's 4-lane and 2-lane scheamtic.

    we need your help is that if the hardware have mistakes or how to configure?

    thanks

  • 0 in reply to Betty Guo
    TI__Expert 5480 points

    HI Betty, 

    if you mean the input reference clock going in to pin 5, the clock requirements do not change whether or not the part is put in to 2 lane or 4 lane configuration. I looked at how the refclk is configured, and it appears to be the same in both schematics. I would suggest if their 25 Mhz clock is getting stuck at 1V, they consult the clock datasheet. 

    Thanks, 

    Sally