[SI-LIST] AW: relation between rise time and trace length
- From: "Havermann, Gert" <Gert.Havermann@xxxxxxxxxxx>
- To: "Mohamed Ali Gazi" <mohamedaligazi@xxxxxxxxx>, si-list@xxxxxxxxxxxxx
- Date: Fri, 11 Dec 2009 09:40:45 +0100
Hi Mohammed,
if your thinking would be correct, then how could anyone possibly send 10GBps
signals over a 19" Backplane?
I think you mixed something up. As long as your tracelength is shorter than the
risetime, you don't have to think too much about impedance controlled traces.
Traces longer than the risetime do need the right impedance to avoid
reflections and other nasty effects. The return path length is not added to the
tracelength of this rule of thumb.
For high speeds make sure the return path length is not exceeding the signal
path length (yet another rule of thumb).
BR
Gert
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-----Ursprüngliche Nachricht-----
Von: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] Im
Auftrag von Mohamed Ali Gazi
Gesendet: Freitag, 11. Dezember 2009 07:02
An: si-list@xxxxxxxxxxxxx
Betreff: [SI-LIST] relation between rise time and trace length
Dear Experts,
I understood from some of the materials that the trace length between the
driver to receiver ( signal path + return path) should be less than the rise
time. Is my understanding correct?
For example if the rise time of a signal is 1ns then the signal trace length
should be less than 3 inches( signal trace length 3 inches and return path 3
inches totally 6 inches = 1 ns of signal travel delay which is equal to rise
time of the signal)
If my understanding is wrong can anybody please provide me with some materials
to understand it. Sorry if this is bit basic question.
Thank you very much.
Mohamed Ali
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- » [SI-LIST] AW: relation between rise time and trace length - Havermann, Gert
