Lee, yes and that is a point that we agree about. I just didn't want your reply to be interpreted as advocating either BS or EC particularly BS across PP, and even worse across thin PP. Steve. At 07:20 PM 12/22/2005 -0800, Lee Ritchey wrote: >Steve, > >Do you mean by PP preperg? If so, that would infer what is often called >broadside coupling or one over the top of the other. If that is what you >mean by this, it's about the worst way there is to route a diff pair and I >would never want to do that. It is really a tough one to get right. > >Lee W. Ritchey >Speeding Edge >P. O. Box 2194 >Glen Ellen, CA 95442 >Phone- 707-568-3983 >FAX- 707-568-3504 > >I just used the energy it took to be angry to write some blues. >Count Basie > > > > [Original Message] > > From: steve weir <weirsi@xxxxxxxxxx> > > To: <leeritchey@xxxxxxxxxxxxx>; Ravindra Johari ><Ravindra.Johari@xxxxxxxxxxxxxxxxxx>; <si-list@xxxxxxxxxxxxx> > > Date: 12/22/2005 6:38:13 PM > > Subject: Re: [SI-LIST] Re: XAUI > > > > Lee, I agree that loosely coupled usually brings fewer issues to deal >with > > than tightly coupled, making it a safer default recommendation. For > > loosely coupled, I would avoid broadside coupling including tandems, > > particularly across PP. If B/S coupled across PP, the registration, and > > therefore coupling can vary quite a bit, especially for narrow traces. >If > > the PP is thin, it just makes it worse. > > > > Steve. > > At 02:17 PM 12/22/2005 -0800, Lee Ritchey wrote: > > >Actually, neither. Coupling doesn't have any benefit. If you can spread > > >the traces out so there is no coupling, you've got the best geometry. >Real > > >world, you can't do this and route a PCB, so route side by side with as > > >much separation as your topology will allow. Then adjust trace widths to > > >give you 100 ohm diff impedance. > > > > > >Lee W. Ritchey > > >Speeding Edge > > >P. O. Box 2194 > > >Glen Ellen, CA 95442 > > >Phone- 707-568-3983 > > >FAX- 707-568-3504 > > > > > >I just used the energy it took to be angry to write some blues. > > >Count Basie > > > > > > > > > > [Original Message] > > > > From: Ravindra Johari <Ravindra.Johari@xxxxxxxxxxxxxxxxxx> > > > > To: <si-list@xxxxxxxxxxxxx> > > > > Date: 12/22/2005 11:19:44 AM > > > > Subject: [SI-LIST] XAUI > > > > > > > > > > > > Hello Gurus!! > > > > > > > > > > > > > > > > Which is a better coupling for running a differential pair at XAUI >Speeds > > > > i.e at 3 Gbps.. > > > > > > > > > > > > > > > > Is it Edge coupled stripline or Broadside coupled stripline.. > > > > > > > > What kind of constraints can I face with these? > > > > > > > > > > > > > > > > Thanks! > > > > > > > > Ravi > > > > > > > > > > > > > > > > > > > > > > > > ------------------------------------------------------------------ > > > > 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 FAQ wiki page is located at: > > > > http://si-list.org/wiki/wiki.pl?Si-List_FAQ > > > > > > > > List technical documents are available at: > > > > http://www.si-list.org > > > > > > > > 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 FAQ wiki page is located at: > > > http://si-list.org/wiki/wiki.pl?Si-List_FAQ > > > > > >List technical documents are available at: > > > http://www.si-list.org > > > > > >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 FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org 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