[SI-LIST] : RE: PCI crosstalk on Dual stripline

About this list Date view Thread view Subject view Author view

From: Doug Hopperstad (doug.hopperstad@qlogic.com)
Date: Tue Nov 21 2000 - 11:29:26 PST


Here is a question that should generate a lot of opinions: When routing PCI
devices, what rules or guidelines are used for parallel and tandem crosstalk
for the given stackup: (The board material is set for FR408 with a
dielectric constant of 3.8)

Dual stripline:
----------------------- Ground Plane (0.5 ounce)
 ------ ------- 5 mil trace layer (0.5 ounce)
 ------ ------- 5 mil trace layer (0.5 ounce)
---------------------- Ground Plane (0.5 ounce)

* The Plane-to-Layer spacing is 8 mils
* The Layer-to-Layer spacing is 10 mils
* The trace width is set for 5 mils (which will provide a 70 ohm trace
impedance)
* The trace-to-trace spacing is set for 5 mils (10 mil pitch)

The traces are routed orthogonal for the most part. The major problem is
that the routing out of the ASIC is hindering the orthogonal routing and
making the tandem crosstalk a big concern.

Doug Hopperstad
QLogic Corporation
doug.hopperstad@qlogic.com

**** 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 : Tue May 08 2001 - 14:30:12 PDT