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LMK04616: propagation delay

Part Number: LMK04616

Greetings,

I want to confirm some info can't be found in datasheet.

What is the propagation delay between OSCin to Clkout(x).
The device uses PLL2 (only) with zero delay mode.

Thank u.

Regards,

  • Hello Mark,

    It's about 7.4 ns using CH6 feedback.

    73,
    Timothy

  • Furthermore,

    The number 7.4ns is a "strange" number for zero-delay.
    If I understand correctly, the propagation delay at non zero-delay will be higher.

    How this number related to 3ns propogation delay when the device is at buffer mode (according to the data sheet)?

    could you explain it in more detail?

    Thank u so much.

  • Hi Timothy,

    Could you please clarify the further inquiry?

    Tks.

  • Hello Mark,

    Reviewing the data again, it was collected using a 122.88 MHz clock.  So if considered from a 'steady-state', the propagation delay could not be more than ~8.14 ns.  Equivalently it may be said that the propagation delay is 7.9 ns - 8.14 ns = -0.24 ns.  In the LMK04616 the reference + forward path vs. feedback path are not balanced out for propagation delay intrinsically and therefore a deterministic, "non-0," delay value is achieved.  However the digital delay can be performed achieve a literal "0" delay from input to output to the resolution of the delay adjustment.  In this case the delay from input to the feedback channel vs. non-feedback channel would be different.

    The difference with the buffer delay this would be forward delay only, vs in a PLL there would not be a forward and reverse path which could impact the final input to output delay.

    73,
    Timothy