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DS90UB925Q-Q1: Eye Opening

Youhei Miyaoka
Expert 4145 points
Part Number: DS90UB925Q-Q1
Other Parts Discussed in Thread: DS90UR241-Q1

Tool/software:

Hi team,

We have question for DS90UB925Q-Q1, could you please check and let us know for eye-opening what is the value of TxOUT_E_O with reference to below image?

Note: this fig from DS90UR241-Q1

Regards,

Youhei MIYAOKA

  • +1
    TI__Mastermind 19645 points

    Hello Youhei,

    In the DS90UB925Q-Q1, there is a similar specification for reading the FPD-Link specification; tBIT

    UI – Unit Interval is equivalent to one serialized data bit width 1UI = 1 / (35*PCLK)

    Additionally, the jitter characteristics of the DOUT+/DOUT- pins are provided as tTJIT output total jitter from typical 0.25 to maximum 0.30 UI. 

    Please let me know if you require additional information.

    Best,

    Miguel

  • 0 in reply to Miguel Bolante
    TI__Expert 4145 points

    Hi Miguel,

    Thanks. I have few more checks;

    1) 1) Is TDJIT=TTJIT/2? 

    2) If they do measurement, is below how we should measure eye opening? This is x-axis ( time), how to judge if eye is open enough on Y-axis i.e. (amplitude)? Is there are requirement for that?

    Regards,

    Youhei

  • +1 in reply to Youhei Miyaoka
    TI__Mastermind 19645 points

    Hi Youhei,

    Youhei Miyaoka said:
    Is TDJIT=TTJIT/2? 

    The TDJIT measurement should be the same specification as TTJIT.

    Youhei Miyaoka said:
    If they do measurement, is below how we should measure eye opening?

    The X axis of the specification is determined by the UI (Unit Interval) of the data rate used. Unit interval specifies minimum time interval between each transition, so for example 3.375 Gbps > 1UI = 0.296 ns

    The maximum total jitter of this example should be 0.3 * UI, so 0.3 * 0.296 ns is this specification.

    For the Y-Axis, the figure specifies differential output voltages, which are characterized in the DC Electrical Characteristics as VODp-p and ΔVOD.

    Please let me know if you have any further questions!

    Best,

    Miguel