re: [SI-LIST] : Guard banding

fangj@binghamton.edu
Mon, 10 Nov 1997 23:02:14 -0500 (EST)

I have a couple of questions regarding the grounded guarding bands. Hope
I can get some answers from this group.

(1) Does anyone aware of any formal analysis on the effects of grounded
guarding bands?

(2) Are there any design guidelines on when grounded guarding bands
should better be used?

(3) Are there any quantitative studies (either analytical or
experimental) on how the interval between grounding vias affects the
crosstalk between traces ?

Jiayuan Fang
fangj@binghamton.edu

On Mon, 10 Nov 1997, Ray Anderson wrote:

>
> The context in which you usually hear about
> "guard traces" is in very high impedance
> analog circuitry where the designer is
> trying to guard a very hi-Z node from
> very minute leakage currents flowing across
> a board or substrate. In these cases, a grounded
> guard trace can be effective.
>
> I tend to agree with Fabrizio, that in
> high speed circuitry where one is concerned
> with AC crosstalk, that the use of grounded
> guard traces may be of dubious value.
>
> So depending on what Ronda was referring
> to when she asked about grounded guard traces,
> the answer could go either way.
>
> Ray Anderson
> raymonda@radium.eng.sun.com
>
>