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    Why return path in PCB is as significant as signal path with an example

    Hi
    It would be Helpful if anyone can provide an example of why return path is significant in PCB design.

    Thanks and Regards
    Sush

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    Re: Why return path in PCB is as significant as signal path with an example

    Hi,

    do an internet search for:
    "return path discontinuities"
    "stripline return path"
    "high speed layout guidelines"
    and so on

    ...and you will find lots of documents, descriptions, tutorials ...

    like this:
    www.ti.com/lit/an/scaa082a/scaa082a.pdf

    Klaus
    Please don´t contact me via PM, because there is no time to respond to them. No friend requests. Thank you.

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    Re: Why return path in PCB is as significant as signal path with an example

    Its important because its 50% of the signal...

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    Re: Why return path in PCB is as significant as signal path with an example

    Nothing happens until you close the current loop.
    That is "the path". Not just the part you think is
    "signal". The "signal" trace should be signal and nothing
    but (in a perfect world). The return, that's a shared
    resource unless you make it likewise clean and single
    purpose.

    Like, you may take a limo to the prom, but you are
    going home on public transportation. So watch where
    you sit, because that tux has a cleaning deposit.

  5. #5
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    Re: Why return path in PCB is as significant as signal path with an example

    Quote Originally Posted by KlausST View Post
    Hi,

    do an internet search for:
    "return path discontinuities"
    "stripline return path"
    "high speed layout guidelines"
    and so on

    ...and you will find lots of documents, descriptions, tutorials ...

    like this:
    www.ti.com/lit/an/scaa082a/scaa082a.pdf

    Klaus
    Thanks Klaus !!

    I also have few Doubts while going through some PCB boards!!

    What does loop inductance got to do with a transmission line!! Will they be resonant at Certain high Frequencies
    say the charecteristic impedance of tx line is Z0= R+jwL so will equating the imaginary part to inductance give the value of Loop inductance?

    Also what are stitching Via's purpose in pcb ?
    searching on google said that stitching vias are used to eliminate the EMI on the signal traces. Apart from this is there any other reason.

    when observing Pcb they have added vias around the the mounting holes can anyone give me an appropriate reason as to why this is done... ?


    Thanks and Regards
    sush

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