[SI-LIST] Re: Netlist or W Elements for HSpice from Cadence Allegro
- From: "Chi Tu" <Chi.Tu@xxxxxxxxxx>
- To: <si-list@xxxxxxxxxxxxx>
- Date: Mon, 2 Aug 2010 11:16:55 -0500
Hello Mani,
To clarify, HSPICE does have the ability to use s-parameter models in
simulation by using an S-element.
1)Here's an example of how to do this for a differential pair s-par
model in Touchstone format:
Sdiffpair inp inn outp outn GND mname=tracemodel
.MODEL tracemodel S TSTONEFILE='../diffpair.s4p' INTDATTYP=RI
INTERPOLATION=LINEAR FMAX@GIG FBASE=9.765625Meg
The FMAX is the max frequency point in your touchstone model.
The FBASE relates to the sampling frequency that you tell HSPICE to use
for doing an IFFT to get time-domain data.
There is a nifty S-parameter Appnote on Solvnet that covers this in more
detail.
https://solvnet.synopsys.com/retrieve/017600.html
You can also refer to Chapter 2 of the "hspice_si.pdf manual to learn
about the other s-element options.
2)Also, the W-element does have an option to reference an s-par model
instead of an RLGC file.
Wdiffpair inp inn gnd outp outn gnd smodel=tracemodel
+ N=2 L='10*.0254'
+ nodemap=i1i2o1o2
.MODEL tracemodel S TSTONEFILE='../diffpair.s4p' XLINELENGTH='5*.0254'
The advantage of calling an s-par model through a W-element is the
ability to scale the length by changing the "L" value.
To scale properly, be sure to set the "XLINELENGTH" to match the
original s-par model length.
The example above takes a 5-inch line and scales it to 10-inch.
Regards,
Chi Tu
Design Engineer
Plexus Technology Group
361 Centennial Pkwy
Louisville, CO 80027
> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx
[mailto:si-list-bounce@xxxxxxxxxxxxx]
> On Behalf Of Mani Ganesan
> Sent: Tuesday, July 20, 2010 12:26 PM
> To: si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] Netlist or W Elements for HSpice from Cadence
Allegro
>
> Hello
> I have a board file and I would like to do a TDR analysis in HSpice.
To
> do
> that I need to create a netlist for HSpice and I need W element (RLGC)
> of
> the trace. I cannot create that by hand. Can anyone tell me whether I
> can
> create the W element or Netlist of a specific differential trace under
> interest from the board file in Cadence? Is there an option in the
tool.
>
> I have a 3d modeling tool. But the touchstone gives only S matrix I
> believe.
> How can I get the W element of the trace so that I can use it in
HSpice?
>
> Thank You
> Mani Ganesan
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