I agree with James and would like to add that another possibility lies in splitting the termination for a T'd signal. e.g. from source to `T' with Zo impedance From `T' to both receivers with 2 x Zo impedance. terminating at the receivers with 2 x Zo resistance. -- Regards, __________ James G Roberts /___ ____ | jrobert@xxxxxxxxxxxxxxxxxxxxx Jim __ / /___/ / jgroberts@xxxxxxxxxx / /_/ /---| | Room: BE436, Hilversum \____/ /_/ Tel: +31 35 687 4308 Fax: 5976 James_R_Jones@xxxxxxxx wrote: > The basic relation is that a shelf will occur at half signal swing at the > receiver that is approx 2 times the time of flight of the stub. This shelf > may introduce unacceptable timing uncertainty. You could fix this problem > by routing two traces from the driver to each of the loads. Use a series > terminator for each line at the source and you should probably simulate to > determine the R values. Beware that this approach is doubly loading the > clock driver, which may or may not have adequate drive strength to keep > adequate edge rate. > > You could also terminate at the teed topology at the receivers to get rid of > the shelf, and once again I would probably simulate in order catch all of > the problems with this. > > Hope this helps, > James R. Jones > > -----Original Message----- > From: Hora Abu [mailto:arageeb@xxxxxxxxx] > Sent: Thursday, January 23, 2003 5:58 PM > To: si-list@xxxxxxxxxxxxx > Subject: [SI-LIST] Stub length of a clock > > Dear SI expert, > > I have two loads that I need to support with one clock. I route the clock > from the generator to half way between the loads and T off to stubs each > going to its target load. I know that the stub needs to be minimize but I > can only make so short. Transmission line theory suggest there is a > relationship between the stub length and signal rise time? does any know > this relation or can point me to an article. > > Thanks > > Hura > > arag abu deeb > > --------------------------------- > Do you Yahoo!? > Yahoo! Mail Plus - Powerful. Affordable. Sign up now > > ------------------------------------------------------------------ > To unsubscribe from si-list: > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field > > or to administer your membership from a web page, go to: > //www.freelists.org/webpage/si-list > > For help: > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field > > List archives are viewable at: > //www.freelists.org/archives/si-list > or at our remote archives: > http://groups.yahoo.com/group/si-list/messages > Old (prior to June 6, 2001) list archives are viewable at: > http://www.qsl.net/wb6tpu > > > ------------------------------------------------------------------ > To unsubscribe from si-list: > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field > > or to administer your membership from a web page, go to: > //www.freelists.org/webpage/si-list > > For help: > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field > > List archives are viewable at: > //www.freelists.org/archives/si-list > or at our remote archives: > http://groups.yahoo.com/group/si-list/messages > Old (prior to June 6, 2001) list archives are viewable at: > http://www.qsl.net/wb6tpu > ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu