Tom With all due respect, a capacitor mounted on a PCB is a very complex mixed TEM/Quasi-TEM/non-TEM 3D structure, which is not amenable to first order spice approximation without a large amount of work. You can start with papers we've placed on our website, where we have shown the first principles necessary to calculate mounted capacitor inductance, correlated our models to measurement, and have further correlated measurements to full 3D full-wave structural simulation of a capacitor. http://www.teraspeed.com/publications.html A few that you might look at are: *//Using Full Wave Solvers for Practical Analysis of Capacitor Mounting Structures * *Considerations for Capacitor Selection in FPGA Designs * *Bypass Capacitor Inductance, Data Sheet Simplicity to Practical Reality * *Bypass Filter Design Considerations for Modern Digital Systems * *System Considerations for Bypass Filter Designs * * Impact of PCB Stack-up and Capacitor Via Design In Power Distribution Design * *High Performance FPGA Bypass Networks* ** best regards, Scott Scott McMorrow Teraspeed Consulting Group LLC 121 North River Drive Narragansett, RI 02882 (401) 284-1827 Business (401) 284-1840 Fax http://www.teraspeed.com Teraspeed® is the registered service mark of Teraspeed Consulting Group LLC tom_cip_11551 wrote: > Hi, > > I am trying to determine an optimum decoupling strategy. I have found > lots of manufacturers data conerning capacitor models, from Murata and > others. But I keep thinking that these models can't possibly take into > consideration the layout footprint, because of process, material and > other variations, like the layer height above copper. > > So, when attempting to model a capacitor in spice or other, what is a > good strategy in trying to take into consideration the footprint itself? > > Yes, I do realize that in some cases, a 3D model can be created, but > that can be very time consuming and I am really only talking about a > first order spice approximation. > > > Thank you to all who respond. > > Tom > > > ------------------------------------------------------------------ > 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