[SI-LIST] Re: HSPICE Field Solver

Marek,

Your problem is most likely one of units.
For example, for trace width you specify:

WIDTH=0.0001016m

which is 0.0001016e-3 meters wide

I believe you meant to have a 4 mil trace width.
Your actual trace width is .004 mils, which is giving you a
DC trace resistance of 9.61063e+06

m is the suffix for milli (e-3), not meters.
All units are in meters unless otherwise specified.

I always check my DC trace resistance in the matrix to see
if I have a units problem in my field solvers.  Not that I would
ever make this same mistake myself!!!!!


regards,

scott


--
Scott McMorrow
Principal Engineer
SiQual, Signal Quality Engineering
18735 SW Boones Ferry Road
Tualatin, OR  97062-3090
(503) 885-1231
http://www.siqual.com


Marek Skibinski wrote:

> Guys,
>
> I am running HSPICE 2001.2 to do SI work on a Backplane. Unfortunately the
> field solver within HSPICE is giving me suspect results. Here is the code
> that I am using for my W element setup:
>
> ___________________________________________________
> * Track shape definiton widths to suit
>
> .SHAPE rect RECTANGLE WIDTH=0.0001016m, HEIGHT=0.00001778m,
>
> * Preliminary layer stack
>
> .LAYERSTACK stack_1,
> +LAYER=(PEC,0.00001778m), LAYER=(getek,0.000381m),
> +LAYER=(PEC,0.00001778m)
>
> * Setting field solver options to high accuracy
>
> .FSOPTIONS opt1_1 GRIDFACTOR=3 PRINTDATA=YES
> +ComputeRo=yes ComputeRs=yes ComputeGo=yes ComputeGd=yes
>
> *-----------------------------------------------------------------------
> * Tx Card T-line
> *
>
> .MODEL tx_card_line W MODELTYPE=FieldSolver,
> +LAYERSTACK=stack_1, FSOPTIONS=opt1_1
> +RLGCFILE=txcardli.rlgc
> +CONDUCTOR=(MATERIAL=copper, SHAPE=rect, ORIGIN=(0m,0.00038989m)),
> +CONDUCTOR=(MATERIAL=copper, SHAPE=rect, ORIGIN=(0.0002289m,0.00038989m))
>
> ________________________________________________________
>
> And here is the resulting rlgc file:
>
> _________________________________________________________
> *SYSTEM_NAME : tx_card_line
> *
> *  ------------------------------------ Z = 4.1656e-07
> *  //// Top Ground Plane //////////////
> *  ------------------------------------ Z = 3.9878e-07
> *       getek   H = 3.81e-07
> *  ------------------------------------ Z = 1.778e-08
> *  //// Bottom Ground Plane ///////////
> *  ------------------------------------ Z = 0
>
> * L(H/m), C(F/m), Ro(Ohm/m), Go(S/m), Rs(Ohm/(m*sqrt(Hz)), Gd(S/(m*Hz))
>
> .MODEL tx_card_line W MODELTYPE=RLGC, N=2
> + Lo =  2.82310e-08
> +       0.00000e+00  2.82310e-08
> + Co =  1.53499e-09
> +       0.00000e+00  1.53499e-09
> + Ro =  9.61063e+06
> +       0.00000e+00  9.61063e+06
> + Go =  0.00000e+00
> +       0.00000e+00  0.00000e+00
> + Rs =  1.05871e+00
> +      -2.46652e-03  1.05871e+00
> + Gd =  9.64460e-11
> +       0.00000e+00  9.64460e-11
>
> ______________________________________________________
>
> The results from the SigXplorer field solver indicate different values by a
> factor of 10 in both capacitance and inductance of the track.
>
> Could you have a look at the code and tell me if there is a problem with
> the field solver or am i just missing something a bit more fundamental.
>
> Thanks for your help,
>
> Marek
>
> **********************************************************
> Marek Skibinski
> Hardware Design Engineer
> Nortel Networks
> Doagh Road, Newtownabbey, Co. Antrim
> BT36 6XA
> Tel: +44 (0)2890363494 (ESN 751-3494)
> **********************************************************
>
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