Hi, Does the coupling type (tight and loose) affect the way that the return current will behave? Someone told me that a tight coupled diff pair return current will be more on the coupled trace than the reference plane. Since the coupling is stronger with the other trace, the electron will tend to flow on the trace rather than on the plane. I'm really not sure about this one, but the doubt is high enough to check how urban this legend is. Regards, Marc-André Filion, ing Concepteur Matériel / Hardware Designer Brioconcept Consulting Inc. 450.681.2779 x2368 -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On Behalf Of steve weir Sent: 1 février 2013 20:27 To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: Loose coupling vs tight at the same time Marc, just to add a little bit to Lee's good comment: The impedance in both even and odd modes is going to change. How much this is going to cause S11 impairment depends on just how tightly you couple in the pin field. If the data rate is reasonably high I encourage you to put what you are considering through a field solver so that you can see what is going to happen to both your reflections and your cross talk. The latter may be the bigger problem with what you are trying to do. Steve. On 2/1/2013 3:33 PM, Lee wrote: > The big thing to worry about is the change in impedance when you go > from tight to loose or the reverse. Any good 2D field solver will > allow you to quantify that. > > -----Original Message----- > From: Marc-André Filion > Sent: Friday, February 01, 2013 2:35 PM > To: SI-LIST mailing list > Subject: [SI-LIST] Loose coupling vs tight at the same time > > Hi, > We’re having a discussion here and I would like to know your thought > about it. > > How bad is it to transition from tight coupling diff signal to loose > coupling signal and vice-versa. We have a case here where we pass-thru > a pin field and we reduce the coupling from loose to tight for 2”and > get back to loose after. > > > > I’m not sure that it’s a good approach. What’s your idea on this? > > > > > > > > Marc-André Filion > > > ------------------------------------------------------------------ > 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 forum is accessible at: > http://tech.groups.yahoo.com/group/si-list > > List archives are viewable at: > //www.freelists.org/archives/si-list > > Old (prior to June 6, 2001) list archives are viewable at: > http://www.qsl.net/wb6tpu > > > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2013.0.2897 / Virus Database: 2639/6074 - Release Date: > 02/01/13 > > ------------------------------------------------------------------ > 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 forum is accessible at: > http://tech.groups.yahoo.com/group/si-list > > List archives are viewable at: > //www.freelists.org/archives/si-list > > Old (prior to June 6, 2001) list archives are viewable at: > http://www.qsl.net/wb6tpu > > > -- Steve Weir IPBLOX, LLC 1580 Grand Point Way MS 34689 Reno, NV 89523-9998 www.ipblox.com (775) 299-4236 Business (866) 675-4630 Toll-free (707) 780-1951 Fax All contents Copyright (c)2012 IPBLOX, LLC. All Rights Reserved. This e-mail may contain confidential material. If you are not the intended recipient, please destroy all records and notify the sender. ------------------------------------------------------------------ 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 forum is accessible at: http://tech.groups.yahoo.com/group/si-list List archives are viewable at: //www.freelists.org/archives/si-list 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 forum is accessible at: http://tech.groups.yahoo.com/group/si-list List archives are viewable at: //www.freelists.org/archives/si-list Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu