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DS90UB927Q-Q1: eye diagram test format

Betty Guo
Expert 7300 points
Part Number: DS90UB927Q-Q1

Hi team,

customer will test 927 eye diagram preformance, need to know the rising edge UI and falling edge UI parameter to do the test format.

Can you provide this parameter for 927 eye diagram test format?

meanwhile, for the 948 eye diagram test, wet the CMLOUTP/CMLOUTN to 360*2, the peak amplitude of CMLOUT will reach to the maximum threshold, which result the eye diagram fail.

we would like to know what recommendation of 948 VOD voltage?

thank you

  • 0
    TI__Guru 56295 points

    Hi Betty, 

    I'm not sure I quite follow the question. If asking for the UI value, it can be calculated with this formula: 1 UI = 1 / (PCLK_Freq. x 35)

    We don't have an eye mask/bilevel values for FPD III, if that is what is being requested. 

    Betty Guo said:
    we would like to know what recommendation of 948 VOD voltage?

    The CML VOD voltage of 948 will be 360mV. Is your comment/question that the eye signal amplitude has a negative offset making it go less than 360mV amplitude?

    We usually only recommend taking an eye diagram measurement to diagnose a gross issue with the FPD III channel such as zero crossings or completely closed eye. In general for performing analysis of the FPD link margin we suggest making use of the Margin Analysis Program (MAP). 

    Regards, Logan