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CDCE62002 Clock Distribution

shadders
Expert 1065 points
Other Parts Discussed in Thread: CDCE62002

Hi,

I am planning to use the CDCE62002 Clock Generator, but due to the distances between the chips (10 cm), i am was going to use a clock distribution circuit - based on discrete logic.

My concern is that in implementing the relevant gates, that i may be introducing phae noise. I can see that i will introduce clock skew, but i am not sure about whether there will be phase noise introduced.

If phase noise is not introduced by a discrete logic, i then begin to consider whether the CDCE62002 with sub 1ps phase noise is really needs to be used.

I have searched the net, but unable to find any texts on the clock generators using a single crystal at the frequency needed, and an inverting logic gate with feedback.

Will such a circuit introduce phase noise - i can only surmise that the variation in the input thresholds will introduce such phase noise, but the duration of this variation etc., is not known - if this is the cause of phase noise ?.

Are there any texts on the optimal approach for a single frequency clock oscillator that has the same phase noise specification as the CDCE62002 ?.

Thanks.

Regards,

Richard.

  • 0
    TI__Prodigy 515 points

    Richard,

    Apologies for the delay on this.  Do you still require assistance on  the CDCE62002?  Typically, any external components to fan-out a clock signal from the CDCE62002 is going to add additional jitter, directly impacting the phase noise.  Are you looking to compare RMS jitter numbers from a single frequency XO vs. what can be achieved with a XTAL + CDCE62002?

    Best regards,

    Brad

  • 0 in reply to Brad Ruzicka
    Expert 1065 points

    Hi Brad,

    Apologies for the late reply.

    I have used a thevinin transmit (CDCE62002) and receive (DAC) resistor topology to reduce the EMI.

    I assume that if the resisotrs remain at a reasonably stable temperature that jitter will be at a minimum ?. Thanks ?.

    Are there any publications on this area of work - it does not seem to be a topic that you can find a good book on detailing the effects of external components on jitter etc. Thanks.

    Regards,

    Richard.