RE: [SI-LIST] : Via Capacitances ...

Dave Hoover (dhoover@mccurdy.com)
Tue, 13 Jul 1999 10:00:08 -0700

The trace did not connect to the reference planes. And the
diameter of the Probe Card was less than 12" (Dia) so the trace
lengths were rather short. So the effect was large proportionately
speaking with regards to the trace size (length). It definitely
dropped the impedance. Doug Brooks has an interesting paper
on Impedance and vias at his webpage.
try http://www.ultracad.com/articles.htm
This one seems to hit the nail on the head and then some.

Dave

-----Original Message-----
From: rbmccammon@mmm.com [mailto:rbmccammon@mmm.com]
Sent: Tuesday, July 13, 1999 06:31 AM
To: si-list@silab.eng.sun.com
Subject: RE: [SI-LIST] : Via Capacitances ...

I think we should consider two cases.

1. A trace encounters a via and then continues on the same plane.

2. A trace encounters a via, goes and goes through its reference plane
and continues on the other side.

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