RE: [SI-LIST] : Guard traces

About this list Date view Thread view Subject view Author view

From: Moran, Brian P (brian.p.moran@intel.com)
Date: Tue Jun 20 2000 - 10:10:34 PDT


Here's my two cents on the subject. In my humble opinion guard traces are
only useful when the trace in question is fairly well removed from the
reference plane such as on the surface layer of a stacked microstrip
configuration. In this case it acts as a more local reference to terminate
fields. However, as someone already said, I do believe you have to stitch
it regularly, or it can become a monopole. I think a better solution is
through careful stack specification and good spacing rules.

Brian P. Moran

Intel Corporation
Platform Design Engineering
brian.p.moran@intel.com
(916) 356-1912

-----Original Message-----
From: Tadashi ARAI [mailto:arap@jdc.paso.fujitsu.co.jp]
Sent: Monday, June 19, 2000 8:04 PM
To: si-list@silab.eng.sun.com
Subject: Re: [SI-LIST] : Guard traces

I'm standing in opposite.

My calculation using XTK showed that there are benefit to reduce
crosstalk with additional guard trace. Wider the guard trace, smaller
noise we can get. Also vias intervals are very effective.

Radiation from clock traces are reduced by guard traces according to
MOM simulations (but not by me), too.

On Thu, 15 Jun 2000 21:22:28 -0700
Mail from dmckean@gte.net described as below:

> Personally?
>
> They're unnecessary.
>
> If done incorrectly, can lead to all sorts of problems.
> If done correctly, have to be stitched every inch or so
> with vias driving up the cost. Adding guard traces leads
> to separating the traces you wish to separate anyway.
> Distance is the best cure for crosstalk. Therefore, IMO,
> it's sort of redundant to use them.
>
> < ducking for cover ... >
>
> Regards, Doug McKean
>
> Sean Murray wrote:
> >
> > I don't know if this has been asked before, but what are the general
> > feelings on the use of guard traces to shield clock lines? Is it worth
> > it, or the required amount of gnd vias prevents this from being a viable
> > solution?

//// /// // / / / / / / / / / /
Tadashi Arai//Platform Developing Dept.,Desktop Prd Div. Fujitsu Limited
arap@paso.fujitsu.co.jp TEL:+81-42-370-7624 Inagi-shi, Tokyo, Japan
/ / / / / / / / / / / // ///

**** To unsubscribe from si-list or si-list-digest: send e-mail to
majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE
si-list or UNSUBSCRIBE si-list-digest, for more help, put HELP.
si-list archives are accessible at http://www.qsl.net/wb6tpu
****

**** To unsubscribe from si-list or si-list-digest: send e-mail to
majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE
si-list or UNSUBSCRIBE si-list-digest, for more help, put HELP.
si-list archives are accessible at http://www.qsl.net/wb6tpu
****


About this list Date view Thread view Subject view Author view

This archive was generated by hypermail 2b29 : Wed Nov 22 2000 - 10:50:41 PST