[SI-LIST] Re: EMI and Power plane card edge clearance distance
- From: "John Phillips" <John.Phillips@xxxxxxxxxxxxxx>
- To: <mschmitt@xxxxxxxxxxxxxxx>,"'SI-List Discussion Group'" <si-list@xxxxxxxxxxxxx>
- Date: Tue, 14 Aug 2001 14:47:20 +0100
This is a ring of vias connecting all ground planes and is placed
around the edge of the card. Spacing between the vias depends on
the frequencies that you are trying to contain.
John
> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx
> [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Michael Schmitt
> Sent: 14 August 2001 14:27
> To: dmckean@xxxxxxxxxxxxxxx; 'SI-List Discussion Group'
> Subject: [SI-LIST] Re: EMI and Power plane card edge
> clearance distance
>
>
>
> Can somebody explain me what "stitch around the edge of the board"
> means, i guess my english is not good enough to understand that.
>
> Regards.
>
>
> Doug McKean schrieb:
> >
> > Hi Mary,
> >
> > > Are you saying that the 20-H rule only works when the board
> > > is bolted to a chassis?
> >
> > Well, yes. If the board is to be say an interface board plugged
> > into a motherboard where it's standing in free space, then you
> > must stitch around the edge of the board to attain the same
> > sort of effect.
> >
> > The whole trick, IMO, of the 20H rule is termination of the
> > 2D interplanar transmission line. Simply cutting back the
> > power planes would tend to have a dispersal effect, not
> > sure about that.
> >
>
> --
> Dipl.-Ing. (FH) Michael Schmitt
> Baumer Ident GmbH
> Entwicklung / Development Department
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