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    OCXO Freq Stability Vs. Layout design guidelines

    Question: What are the layout guidelines that will allow me to minimize the Y1 mil & Y2 mil sizes (see attached picture) such that the below 10MHz OCXO frequency stability will not have a performance degradation?
    Do I have to place the GND between the OCXO out to Vc etc. or maybe I can remove it?
    What is the required distance between OCXO out and GND? can it be minimal as PCB manufacture allows?

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    Re: OCXO Freq Stability Vs. Layout design guidelines

    What has worked for me, is to not place ANY copper traces or planes below the OXCO's footprint. They form an unintended heat sink.

    If you are using a ground or Vcc plane, place a keep-out area around the OXCO.
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    Re: OCXO Freq Stability Vs. Layout design guidelines

    -I'd prefer to use a separate GND layer because GND will also act a heat-sink if OCXO is properly placed..
    Y1 width depends on the Desired Impedance for that OCXO.If this impedance is somehow maintained,no problem.Because OCXO will see this Impedance as a Load ( of course with actual load together ) therefore it may impact the performance of OCXO.



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    Re: OCXO Freq Stability Vs. Layout design guidelines

    Do you think i can remove the gnd line or at least make y1 smallest for instance 4mil or my 50 ohm will not be able to be maintained?
    If gnd will be removed i lose my sheild between ocxo out and the dc lines wouldn't i ?
    Do i need to worry about this gnd line shield between the ocxo out and dc lines?

    - - - Updated - - -

    How much keep out between ocxo out line and dc lines?do i need the GND line to shelid between them?
    Im talking only about the top layer...
    bottom is full GND



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    Re: OCXO Freq Stability Vs. Layout design guidelines

    Use double side PCB and assign the Bottom layer as a pure GND then place copper pour between OCXO Ouput and Vcc,Vdd with Via stitching.
    -Since whole Bottom layer will be GND, Transmission Line can be easily calculated.
    -You will be placing a isolation copper pour between the Output and others so output will not be victim..



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    Re: OCXO Freq Stability Vs. Layout design guidelines

    Thanks, what is the smallest keep out (Y1) between the copper pour (pour you mean Y2 is minimal?) you have mentioned and the ocxo out?
    I forgot to mention that pcb is flexible, is it possible to do via in flexible pcb?



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    Re: OCXO Freq Stability Vs. Layout design guidelines

    Quote Originally Posted by levnu View Post
    Thanks, what is the smallest keep out (Y1) between the copper pour (pour you mean Y2 is minimal?) you have mentioned and the ocxo out?
    I forgot to mention that pcb is flexible, is it possible to do via in flexible pcb?
    If the substrate is flexible, vias are possible-to my knowledge-in flexible pcbs..So, you can calculate convenient dimensions for ocxo output transmission line as "guided coplanar waveguide".
    But this is not extremely important because the frequency is very low, flexible structure cannot maintain the characteristic impedance in every position.But it doesn't matter much..



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