FW: [SI-LIST] : RE: PCI routing rules

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From: Ron Miller (rmiller@Brocade.COM)
Date: Thu Oct 12 2000 - 18:50:37 PDT


> -----Original Message-----
> From: Ron Miller
> Sent: Thursday, October 12, 2000 6:47 PM
> To: 'Rick Brooks'; Ron Miller
> Subject: RE: [SI-LIST] : RE: PCI routing rules
>
> Right
>
> I got confused between 1/2 velocity for FR4(Er~40
> AND 2 x for round trip and was
> stupid enought to depend on memory.
>
> Sorry Guys
>
> Ron
>
> -----Original Message-----
> From: Rick Brooks
> Sent: Thursday, October 12, 2000 2:24 PM
> To: Ron Miller
> Subject: RE: [SI-LIST] : RE: PCI routing rules
>
> Ron,
> I thought that 85 ps per inch was the inverse speed (prop delay) of light in a vacuum.
> Isn't it more like 160 to 180 ps per inch on FR-4, depending on microstrip or stripline?
>
> - Rick
>
>
>
> -----Original Message-----
> From: Ron Miller [SMTP:rmiller@Brocade.COM]
> Sent: Thursday, October 12, 2000 8:49 AM
> To: 'JNH'; Doug Hopperstad
> Cc: si-list@silab.eng.sun.com
> Subject: RE: [SI-LIST] : RE: PCI routing rules
>
> Try 85 ps per inch one way for FR4.
>
> which is closer to 6 inches per ns.
>
> Ron Miller
>
> > -----Original Message-----
> > From: JNH
> > Sent: Wednesday, October 11, 2000 4:59 PM
> > To: Doug Hopperstad
> > Cc: si-list@silab.eng.sun.com
> > Subject: RE: [SI-LIST] : RE: PCI routing rules
> >
> > Doug,
> > Based on rule of thumb, the propagation delay of PCB is about 4 inch/ns including loading, the round trip propagation delay for PCI speedway has to be 10ns. Therefore, the maximum trace length for PCI is 4 inch/ns x 10ns / 2 = 20 inch.
>
> >
> > I hope it helps to you.
> >
> > Best Regards,
> >
> > John Lin
> > Quanta Computer Inc.,Taiwan, R.O.C.
> > Email: John@quantatw.com
> > Tel: 886+3+3979000 ext. 5183
> >
> >
> > -----Original Message-----
> > From: Doug Hopperstad [ < <mailto:doug.hopperstad@qlogic.com>>]
> > Sent: Thursday, October 12, 2000 3:18 AM
> > To: 'si-list@silab.eng.sun.com'
> > Subject: [SI-LIST] : RE: PCI routing rules
> >
> >
> > Does anyone have any information on PCI routing rules. I am trying to
> > determine the maximum trace length between PCI devices and have been
> > struggling with the 10nS time margin. Is there a formula to determine the
> > maximum trace length between PCI devices?
> >
> > Doug Hopperstad
> > QLogic Corporation
> > doug.hopperstad@qlogic.com
> >
> >
> >
> >
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