Lynne, if by long you mean a trace that is multiple UI's long, then yes a damping resistor in the middle of the line isn't of much benefit. However for lines that are sub one UI, there are any number of situations where a damping resistor mid-trace improves signal integrity. The original question does not have a global answer. As others have pointed out a "best" scheme is only best when it meets all the design requirements with fewer drawbacks than alternatives. Regards, Steve. At 09:39 AM 3/2/2007, Lynne D. Green wrote: >Hello, Saril, > >Simulation is important for determining an acceptable termination scheme, >especially with multiple drivers on a bus. For example, simulation will >show that placing a series resistor in the middle of a long trace produces >no improvement in signal integrity. Since only one driver is driving at a >time, one would do one simulation suite for each driver. > >Remember that each time a trace branches, there is an impedance >discontinuity. Once you have a layout, you will probably want to run >post-layout simulations. > >Regards, >Lynne > > >"IBIS training when you need it, where you need it." > >Dr. Lynne Green >Green Streak Programs >http://www.greenstreakprograms.com >425-788-0412 >lgreen22@xxxxxxxxxxxxxx > > >-----Original Message----- >From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On >Behalf Of Saril >Sent: Friday, March 02, 2007 12:30 AM >To: si-list@xxxxxxxxxxxxx >Subject: [SI-LIST] Termination Topology for Bidirectional Bus > >Hi, >What would be the best termination topology for a Bidirectional Data bus? > >Is it a good thought to place the series termination resistor in the middle >of the trace? > >Also when there are mulitple devices on the bus how can we boil down the SI >issues. > >Its clear that HyperLinx can help on this but, it would be great to know a >generic rule. > > >Thanks in advance.. > >Best regads >Saril Kaiprath >Design Engineer >Fkextronics Design, Bangalore > > > >____________________________________________________________________________ >________ >Do you Yahoo!? >Everyone is raving about the all-new Yahoo! Mail beta. >http://new.mail.yahoo.com >------------------------------------------------------------------ >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 technical documents are available at: > http://www.si-list.net > >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 technical documents are available at: > http://www.si-list.net > >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 technical documents are available at: http://www.si-list.net 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