Heyfitch
Unless the simulated losses are verified by comparison with the
measured s-parameters of real cables and found to be within .5 db across the
band and within about 5 degrees of phase to 13 Ghz I for one will not accept
any model. The bottom line is the congruence with real world and not
mathematical treatise.
HP Mds/ADS meets these criterion and I will stay with the winner.
Ron
"Heyfitch, Vadim" wrote:
>
>
> XFX field solver (from Quad) among other parameters outputs Rs and G
> - frequency dependent resistance and shunt conductance (accounting for the
> skin resistance and the dielectric dipole relaxation losses, respectively).
> These parameters are extracted based on assumption that
> Rskin(freq)~sqrt(freq) and G(freq)~freq. Same assumption is made in HSPICE
> W-elements. However, I believe, that XFX-extracted parameters Rs and G
> should be scaled by the factors sqrt(4*pi) and 2*pi respectively to be used
> in W-elements. These scaling coefficients DO NOT account for necessary unit
> conversion (from mils to meters, etc.). I arrived to these scaling factors
> by comparing the original Telegrapher equations on page 21-80 of
> "Star-Hspice Manual, Release 1998.2" with those in Quad manual. My concern
> there is that these equations in Hspice manual might be given there only as
> an example, and thus are accurate only to some factor.
>
> Would anyone care to comment?
>
> 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?
>
> Thank you all.
>
> Vadim Heyfitch
> Intel, High-end Sever Division
>
> **** To unsubscribe from si-list: send e-mail to [email protected]. In the BODY of message put: UNSUBSCRIBE si-list, for more help, put HELP. si-list archives are accessible at http://www.qsl.net/wb6tpu/si-list ****
--
Ronald B. Miller _\\|//_ Signal Integrity Engineer
(408)487-8017 (' 0-0 ') fax(408)487-8017
==========0000-(_)0000===========
Brocade Communications Systems, 1901 Guadalupe Parkway, San Jose, CA 95131
[email protected], [email protected]
--------------B82C143636770253B2D5EBAC
Content-Type: text/html; charset=us-ascii
Content-Transfer-Encoding: 7bit
<!doctype html public "-//w3c//dtd html 4.0 transitional//en">
Heyfitch
Unless the simulated losses are verified by comparison with the
measured s-parameters of real cables and found to be within .5
db across the
band and within about 5 degrees of phase to 13 Ghz I for one
will not accept
any model. The bottom line is the congruence with real world
and not
mathematical treatise.
HP Mds/ADS meets these criterion and I will stay with the winner.
Ron
"Heyfitch, Vadim" wrote:
XFX field solver (from Quad)
among other parameters outputs Rs and G
- frequency dependent resistance and shunt conductance (accounting
for the
skin resistance and the dielectric dipole relaxation losses, respectively).
These parameters are extracted based on assumption that
Rskin(freq)~sqrt(freq) and G(freq)~freq. Same assumption is made in
HSPICE
W-elements. However, I believe, that XFX-extracted parameters Rs and
G
should be scaled by the factors sqrt(4*pi) and 2*pi respectively to
be used
in W-elements. These scaling coefficients DO NOT account for
necessary unit
conversion (from mils to meters, etc.). I arrived to these scaling
factors
by comparing the original Telegrapher equations on page 21-80 of
"Star-Hspice Manual, Release 1998.2" with those in Quad manual. My
concern
there is that these equations in Hspice manual might be given there
only as
an example, and thus are accurate only to some factor.
Would anyone care to comment?
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?
Thank you all.
Vadim Heyfitch
Intel, High-end Sever Division
**** To unsubscribe from si-list: send e-mail to [email protected].
In the BODY of message put: UNSUBSCRIBE si-list, for more help, put HELP.
si-list archives are accessible at http://www.qsl.net/wb6tpu/si-list
****
--
Ronald B. Miller _\\|//_ Signal Integrity Engineer
(408)487-8017 (' 0-0 ') fax(408)487-8017
==========0000-(_)0000===========
Brocade Communications Systems, 1901 Guadalupe Parkway, San Jose, CA 95131
[email protected], [email protected]
--------------B82C143636770253B2D5EBAC--
**** To unsubscribe from si-list: send e-mail to [email protected]. In the BODY of message put: UNSUBSCRIBE si-list, for more help, put HELP. si-list archives are accessible at http://www.qsl.net/wb6tpu/si-list ****