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LMK00308: Latency variation Regarding

Deva Guru
Prodigy 205 points
Part Number: LMK00308
Other Parts Discussed in Thread: LMK00804

Hi,

        We are planning to use this clock buffer LMK00308 to a PLL in our design. Whether the propagation delay and skew will be same for every power ON or changes after next power ON? Kindly provide changes in propagation delay and skew for every power ON of the IC. for tuning the PLL.

  • 0
    TI__Genius 9250 points

    Hi Dave,

    It should be same for every power on cycle if the condition like supply voltage, temperature etc are same. But a good way is to account for maximum value listed in the datasheet in the design. Because, you can expect variations up to that value over temperature, supply voltage and process.

    Best,

    Asim

  • 0 in reply to Asim Khan
    Prodigy 205 points

    Hi Asim Khan,

    Thanks for your reply,

    It is mentioned on the Data Sheet that the Part to Part Skew is 80 to 120ps and output skew is 30 to 50ps. Our requirement needs phase matching around ~10ps.

    so please reconfirm that the latency will be fixed for 2 or more parts under same voltage and temperature. so that we can eliminate the fixed latency by calibration.

    Can you also suggest any better parts for our requirement of low skew?

    Thanks,

    Deva

  • 0 in reply to Deva Guru
    TI__Genius 9250 points

    Hi Deva,

    If both parts are operating at same input signal, loading, voltage and temperature. You would expect 120 ps maximum part to part skew. This should be accounted because its true for any selected outputs on both parts. 

    LMK00804 is a universal type buffer, can you provide a more specific detail on output and input driver type, number of inputs and outputs required that you are using currently so we can look up a better part in our portfolio. 

    Best,

    Asim