Re: [SI-LIST] : Incorporating 3-d passive circuit models into SPICE

Fred Balistreri (fred@apsimtech.com)
Fri, 24 Apr 1998 15:56:04 -0700

Mike Degerstrom wrote:
>
> The recent post by Julia and the response from Dmitri (I've included
> the messages below) are very closely related to a modeling capability
> that I've been seeking.
>
> Most specifically, we are able to take both s-parameter TDR
> measurements of structures such as vias, connectors, packages
> and so on to determine the electrical characteristics for these structures.
> We next want to extract from those measurements a suitable model
> with which to perform a transient simulation.
>
> Now one could certainly develop an equivalent circuit representation
> composed of passive elements (R, L, and C) for the structure, then
> simulate to compare to the measured data to validate the model. But
> in practice this becomes more difficult - especially as applications
> begin to require multi-Ghz clock rates.
>
> Therefore, I am wondering if anyone has taken frequency measurements
> such as s-parameters and found a reliable method to approximate the
> poles and zeros? If so, do you use the Laplace approach mentioned by
> Dmitri to incorporate the model into a transient circuit simulation?
>
> Mike
>
> On Apr 23, 4:23pm, Dmitri Kuznetsov wrote:
> > Subject: Re: [SI-LIST] : Ferrite Beads in HSPICE
> > Julia Nekrylova wrote:
> > >
> > > Hi,
> > >
> > > Does anybody know the easy way to incorporate ferrite beads
> > > (frequency-dependent resistors/inductors) into HSPICE
> > > transient analysis?
> > >
> > > Thanks
> > >
> > > Julia Nekrylova
> > > N.E.T.
> >
> >
> > Hi Julia,
> >
> > You can implement frequency-dependent resistors and inductors in Hspice
> > using frequency-dependent controlled current or voltage sources, the
> > LAPLACE function in G or E elements. It lets you specify the frequency
> > dependence in a pole-zero form or as a frequency table. The pole-zero
> > form is simulated faster and more accurately.
> >
> > There is also magnetic core model for L elements (inductors). That one
> > accounts not only for the frequency dependence but also for the
> > nonlinear hysteresis effects in ferromagnetics.
> >
> > Dmitri
> >
> > =======================================================
> > Dmitri Kuznetsov, Ph.D.
> > R&D Engineer, Hspice Group
> > Avant! Corporation
> > e-mail: vdm@avanticorp.com
> > =======================================================
> >-- End of excerpt from Dmitri Kuznetsov
>
> --
> _______________________________________________________________
> Mike Degerstrom Email: degerstrom.michael@mayo.edu
> Mayo Clinic - Gugg. Bldg. RM 1011-B Phone: (507) 284-3292
> Rochester, MN 55905 FAX: (507) 284-9171
> WWW: http://www.mayo.edu/sppdg/sppdg_home_page.html
> _______________________________________________________________
We do the same approach as Hspice using Laplace transfer functions. We
have a tool that reads in the S parameters, does a curve fit and then
automactically makes the Laplace transfer functions for you that run
in Spice.

Best Regards,

-- 
Fred Balistreri
fred@apsimtech.com

http://www.apsimtech.com