Volkmar,

Thanks for responding to this I just ran into a situation where another designer
had only grounded their shield in one place.  I thought it was wrong and I
typically ground my shields every inch or so.  I'm glad I insisted the change be
done to the shield and I feel better knowing others are also using this
strategy.

This forum is GREAT!

Cyrus




Volkmar Huss <[log in to unmask]> on 07/27/99 01:35:05 AM

Please respond to [log in to unmask]

To:   [log in to unmask]
cc:    (bcc: Cyrus Ringle/Inter-Tel)
Subject:  Re: [DC] Ground Shield Tracks




Adam,

guarded or shielded traces can be very useful to prevent coupling into a
sensitive trace or from a trace with very short rise time, even on a multilayer
board. But make sure that you ground your ground trace every 1" or so. That way
you keep the shield from becoming an antenna itself.

Volkmar

Hawes, Adam wrote:

>         I feel sure this is probably an issue for a lot of PCB
> designers......
>
>         Recently, I have come across an increasing number of engineers who
> wish to have certain tracks on multilayer PCB's shielded by ground traces
> running adjacently. It seems to be a case of jumping on the bandwagon to me
> because we never used to do this until about 12 months ago.
>
>         I was under the impression that ground tracks only served a useful
> purpose on 1or 2 layer boards and that on a multilayer they were essentially
> a waste of space as most of the capacitive coupling would be straight to the
> ground plane.
>

 (cut)



--
  Volkmar Hu



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