RE: [SI-LIST] : Q: HSPICE w-elements' RLCGs - conversion coeffici

Heck, Howard ([email protected])
Fri, 9 Apr 1999 15:36:29 -0700

Pat, your old buddy (as far as he knows anyway) Steve Hall has done some
work with Lambda. He can also tell you that XFX does not give accurate
values for Rs.... hh

-----Original Message-----
From: Pat Zabinski [mailto:[email protected]]
Sent: Friday, April 09, 1999 1:34 PM
To: [email protected]
Subject: Re: [SI-LIST] : Q: HSPICE w-elements' RLCGs - conversion
coefficients from XFX

SI-List'ers:

Sorry for any inconvenience I might have caused, but upon further
review, I mis-referenced the wrong paper. Although the Wheeler
paper is a "definite-read" to SI engineers, the paper I meant to
reference was:

TI Effect of Surface Roughness on Eddy Current Losses at
Microwave Frequencies
AU Samuel P. Morgan, Jr.
SOURCE Journal of Applied Physics
VOLUME 20
DATE April, 1949
PP 352-362

Pat

P.S. If you haven't noticed, my personal library of journal papers
dates back a bit. It's amazing how much of this was done in the
40's & 50's, yet we continue to re-invent the stuff.

On Apr 7, 2:04pm, Pat Zabinski wrote:
> Subject: Re: [SI-LIST] : Q: HSPICE w-elements' RLCGs - conversion coeffici
> Vadim,
>
> Back in 1942, Harold Wheeler went through the analytics to derive
> the equivalent to "lambda" for various forms of surface roughness
> (e.g., rectangular, triangular, etc). In his paper referenced
> below, lambda varies depending up several factors, primarily
> the RMS surface roughness and skin depth (i.e., frequency and
> material properties). He was able to show how lambda could
> reach 2.
>
> TI Formulas for the Skin Effect
> AU Harold A. Wheeler
> SOURCE Proceedings of the IRE
> DATE September, 1942
> PP 412-424
>
> Obtaining a copy of this paper would be an excellent start in
understanding
> the skin effect on effective resistance.
>
> Pat Zabinski
>
>
> >
> > Another issue... XFX provides an optional fudge factor "lambda" that
> > effectively accounts for copper plane/trace surface roughness. This
fudge
> > factor effectively scales the default copper resistivity in the skin
layer.
> > The default value of "lambda" is 1.
> >
> > Has anyone of you done any study as to what this Lambda should be? How
does
> > this value vary (if at all) from one board vendor to another ? Is there
any
> > particular value for Lambda if one is going to use XFX' data with Hspice
> > W-elements?
>
> --
> Pat Zabinski ph: 507-284-5936
> Mayo Foundation fx: 507-284-9171
> 200 First Street SW [email protected]
> Rochester, MN 55905 www.mayo.edu/sppdg/sppdg_home_page.html
>
>
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>-- End of excerpt from Pat Zabinski

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