Mike
On Jul 9, 9:50am, Ron Miller wrote:
> Subject: Re: [SI-LIST] : Via Capacitances ...
> Doug
>
> I modeled a via some time back with ground planes and
> clearance holes through it. I had intended to use the capacitance
> to make up for an inductance and needed 300 ff.
>
> I used an OEA field solver Metal and to my amazement there was
> hardly any capacitance. I surmised that this was due to the small
> area of the ground planes in tha horizontal direction. Since I needed
> capacitance I added some big fat ground vias all around the signal
> via, and got the 300 ff.
>
> Also, HP ADS which is the cadillac of RF simulators models vias
> as inductor, as does Touchstone before EEsof got swallowed up by
> HP.
>
> Ron
>
> Douglas McKean wrote:
>
> > Could someone give rough estimate
> > of via capacitance?
> >
> > I'm thinking the orientation of the traces
> > connected to the via have a major impact.
> >
> > For instance, an .062 board with a via
> > from one side to the other, different
> > capacitances would be had with the two
> > following constructions ...
> >
> > I. Top Trace
> > -------------
> > |via
> > -------------
> > Bottom Trace
> >
> > II. Top Trace
> > -------------
> > |via
> > -------------
> > Bottom Trace
> >
> > Ideas? Comments?
> >
> > Regards, Doug McKean
> >
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> --
> Ronald B. Miller _\\|//_ Signal Integrity Engineer
> (408)487-8017 (' 0-0 ') fax(408)487-8017
> ==========0000-(_)0000===========
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>-- End of excerpt from Ron Miller
-- _______________________________________________________________ Mike Degerstrom Email: [email protected] Mayo Clinic 200 1st Street SW Gugg. Bldg. RM 1042A Phone: (507) 284-3292 Rochester, MN 55905 FAX: (507) 284-9171 WWW: http://www.mayo.edu/sppdg/sppdg_home_page.html _______________________________________________________________**** To unsubscribe from si-list: send e-mail to [email protected]. In the BODY of message put: UNSUBSCRIBE si-list, for more help, put HELP. si-list archives are accessible at http://www.qsl.net/wb6tpu/si-list ****