Thanks in advance,
Chris Rode
RCI
Jon Keeble wrote:
> >At 02:09 PM 3/23/99 -0800, you wrote:
> >>>>>
> >> Hi all,
> >> I am trying to find the effects of the gaps on the ground plane for
> >> the high-speed circuits.
> >> Even though I have a couple of references about the via, which has the
> >> ground gap problem, I need more specific data about the ground gap
> >> problem regarding the gap size, gap location.....
> >> Either measured data or simulated data will be fine ( papaers or
> >> refernce book...)
> >> Looking forward to your answers.
> >>
> >> Thanks
> >> Sangil Lee
>
> The high frequency component of return current in a plane is concentrated
> under the track.
>
> I recall a number of 90% within 1.5 times the track-plane distance.
>
> So intuitively one might expect less effect if the track is close to the
> plane.
>
> Say the vias are 50 drilled 16 with 10 clearance. This makes a bridge of
> copper between voids of
>
> 50 - (16 + 2x10) = 14.
>
> Best result would be obtained if the track follows the centre line of the
> bridge (good argument for gridded routing).
>
> If the above is correct, then the above geometry would support a track to
> plane distance of upto 10.
>
> Jon Keeble
>
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