Dear All, At 1 GHz, the LINPAR field solver (available from Artech House) gives 48.08 ohms. Doug Brooks wrote: >As an added reference, the new Polar Quicksolver gives Zo for these >dimensions as 47.38 Ohms > >The new UltraCAD differential calculator (single ended calculations are >free) does not allow a value for H less than 4 mils, BUT, you can scale >everything up by a factor of two (check this out with the Polar calculator, >you get the same result) and when you do that the UltraCAD calculator gives >a value for Zo of 48.5 Ohms. The new UltraCAD calculator will also do >differential calculations, but a license is required. > >Doug Brooks > > >At 02:28 PM 4/29/2005, Graham Davies wrote: > > >>This is, of course, related to my search for a good 6-layer stackup. >> >>What is the impedance of a PCB trace (microstrip) with the following >>parameters: >>Width ......................... 6.00 mil >>Height above return plane ..... 3.20 mil >>Thickness ..................... 1.35 mil (1 ounce copper) >>Dielectric rel. permittivity .. 4.2 >> >>These are the answers I get from various tools: >> >>41... ohms (http://www.icd.com.au/) >>41.69 ohms (http://www.emclab.umr.edu/pcbtlc/microstrip.html) >>41.69 ohms (TraceSim version 1.0.0) >>41.69 ohms (http://www.technick.net/public/code/cp_dpage.php? >>aiocp_dp=util_pcb_imp_calculator) >>41.7 .ohms (http://www.sunmantechnology.com/resources/cal_cat00.shtml) >>46.14 ohms (ZTOOL Impedance Calculator V1.2) >>47.31 ohms (http://www.rogers-corp.com/mwu/mwi_java/mwij_vp.html) >>50.89 ohms (http://www.csgnetwork.com/boardrunimpcalc.html) >>51.27 ohms (TxLine version 1.1) >> >>Does anyone have an idea as to why these calculators give results >>that vary by 20% and which are more reliable? >> >>Graham. >> >> > > >------------------------------------------------------------------ > > -- Paul A. Levin Senior Principal Engineer Xyratex, Manhattan Beach (310) 372-7352 - home & office (310) 291-8199 - cell ------------------------------------------------------------------ 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