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PCI Signal loading
- To: Mailing List Recipients <pci-sig-request@znyx.com>
- Subject: PCI Signal loading
- From: scaramouche@vnet.IBM.COM
- Date: Fri, 6 Feb 98 18:15:56 EST
- Resent-Date: Fri, 6 Feb 1998 15:30:03 -0800
- Resent-From: pci-sig-request@znyx.com
- Resent-Message-ID: <"jG7lD2.0.ID2.kcvsq"@electra.znyx.com>
- Resent-Sender: pci-sig-request@znyx.com
Impedance of the signal traces through the PCI connector tabs can be
increased by cross stiching under the tabs instead of a solid ground
or power plane. This will still provide sufficient isolation between
opposing tabs, while providing better control of the trace impedance.
I believe the spec says that an expansion board must have an unloaded
trace impedance characteristic of 60-100 ohms on the shared lines.
(50 ohms was mentioned in Kim's note.)
-
Bill Zevin