Hi all, let’s assume a circuit is switching with 210psec and the signal propagation speed = energy propagation speed is 70psec/cm. The access of the switching device to charges needed for the switching is restricted to a circle (sphere) of 3cm. Beyond 3cm a thing like (ideal?) ground is not defined anymore (!), which means none of the electrons outside the 3cm circle can reach the switching device during the switching event of 210psec. And the electrons outside the 2cm circle reach the device only after 140psec, which means pretty delayed. Just looking at this, I have understanding problems with modelling techniques, assuming e.g. Ideal Ground. At high speed conditions on a PCB, I have problems with ECAD systems, which use TEM ( e.g. 2D solver), with quasi static TEM solutions, with PEEC without retardation, which ignore losses and/or and the frequency dependence of R,L,C, with algorithms, which approximate the Maxwell Equations, with the assumption of ideal ground. Even Spice is such a tool, if non ideal ground assumptions are left out in the applied Spice model. I call these tools conventional tools with which it is however possible to handle large complex structure in acceptable computer running times. But these tools ignore also via- via coupling and via –ground plane structures and just miss with their answers the boat at high speed. Especially when it is claimed that those conventional tools are High Speed PCB analysis tools. But most of the traditional tools on the market do this. Did the guys, who claim the high speed modelling capabilities of conventional tools forget all the nice things they learned at the university ? Some ways around this dilemma are shown under www.mentor.com/germany/veranstaltungen/hsconf/ in the paper “High-Speed Design Analyse: Vergleich von Messung und Simulation“. I am very interested to learn more about the opinion, that Hyperlynx is a 3GHz analysis tool or that Hspice can analyze 10GB/sec nets without having the precise information within that Hspice run about all the net discontinuities and the interaction of these nets with their power system through the net vias? The 2 examples Hyperlynx and the straight forward used Hspice are only examples representing the other conventional tools using similar techniques. Ekkehard Naveen Reddy wrote: > Hi Everybody: > I need to perform some high speed simulations (over 3GHz) for my > backplane and I currently have the Mentor HyperLynx tool. I have run > into a little problem. HyperLynx needs IBIS models for simulation > purposes, whereas most of the vendors provide only spice models and not > IBIS. Although HyperLynx can convert Spice models to IBIS, it does need > a Spice simulator to do that. > > I am a little confused here and am hoping I can have these questions > answered. > > 1. Can I use just Hspice to perform all my high speed simulations or is > HyperLynx a better tool for this application? > 2. Has anyone had experience with converting 3D spice models to IBIS? > What are the tradeoffs? > 3. HyperLynx has three levels of licenses - regular, EXT and GHZ. Which > one should I be using? > > Thanks in advance. > > -Naveen. > > > ------------------------------------------------------------------ > 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 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 > > -- EFM Consulting Dr. Ekkehard Miersch Dresdener Str.6 D-71101 Schoenaich Germany Tel. +49 (0)7031-6571-13 Fax/Tel. +49 (0)7031-6571-14 mobile : +49 (0)172 72 444 55 miersch@xxxxxxxxxxxxxxxxx EFM.Miersch@xxxxxxxxxxx ------------------------------------------------------------------ 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 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