[SI-LIST] Re: Hyperlynx vs. Hspice
- From: Chris Cheng <chris.cheng@xxxxxxxxxxxx>
- To: "'signalintegrity@xxxxxxxxxxx'" <signalintegrity@xxxxxxxxxxx>,jonpowell@xxxxxxxxxxxx
- Date: Fri, 26 Sep 2003 16:25:45 -0700
Naveen,
The real question you have to ask yourself is what is the correct strategy
to design these >GHz systems.
The last time I remember I did a full extraction of the PCB and back
annotate with simulations to analyze SI and timing was over ten years ago.
The truth is for the past few years, especially when buses go above GHz, I
found myself using the ruler or measurement tool on a post route PCB design
more than SPICE or any analog simulators. The performance requirement is
high enough that all the analysis has to be done up front before you connect
a single dot in your PCB routing tool. Min/max bus length, stub length
allowance, parallelism spacing and match length requirement etc have to be
well analyzed and spec out before you route your PCB. When the board is
done, you use your DRC checker or measurement tool to make sure the routing
is done the way the rules require and you send the board out. If you think
you can just throw the board to a PCB designer and use ANY tool (SPICE or
Hyperlynx or whatever) to analyze the results to give yourself a go or no go
on the post route nets, you will be in for a big surprise when bad things
happen.
You also mentioned designing backplanes. I will be really impressed if any
of the extraction tools can properly exact mulitple nets from mulitiple
board and couple them with the proper connector models and automatically do
the analysis for you.
I gave up on the SPICE vs. IBIS argument long time ago so for those who put
their money where their mouth is and really use IBIS to analyze multi GHz
system, good for you. Like Eminem says, will the real Gb/s IBIS users please
stand up, please stand up....
-----Original Message-----
From: Stephen Zinck [mailto:signalintegrity@xxxxxxxxxxx]
Sent: Friday, September 26, 2003 3:33 PM
To: jonpowell@xxxxxxxxxxxx
Cc: naveenr@xxxxxxxxxxxxxxx; si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: Hyperlynx vs. Hspice
FYI...
Another tool that extracts board level topologies (uncoupled and coupled
tlines - T and W elements, terminations, vias, etc.) from Allegro, Pads
and others? is SIAuditor from Sisoft (sisoft.com). It also provides a
host of other features (crosstalk, SSO, static timing analysis among
many more) that runs ontop of Hspice. And because the tool can utilize
IBIS models that can be "test-benched" against the real encrypted Hspice
model, you can do board level pre and post route SI and timing analysis
with these "verified" IBIS models in an short amount of time. They say
it analyzes a net just as fast as SpectraQuest because of this! And it
can be "server-farmed" if needed on Solaris/WINX. Sounds like I am
selling the tool (I'm not) but this sort of tool could prove very useful
when many highly accurate simulations are required - which is why I am
evaluating it :-).
Good luck.
Steve
Stephen P. Zinck
Interconnect Engineering
25 Bennett Lot Road
South Berwick, ME 03908
Phone - (207) 384-8280
Fax - (207) 384-5388
Email - szinck@xxxxxxxxxxxxxxxxxxxxxxxxxxx
Web - www.interconnectengineering.com
Jon Powell wrote:
>Converting HSPICE models to IBIS is not normally a job for a novice (in
>either SPICE, IBIS, or the expected circuit performance). For modern
devices
>you have elements that cannot be supported by IBIS or IBIS-only simulators.
>There are some mixed SPICE/IBIS simulators out there but if your HSPICE
>models are encrypted, then you will still need a copy of HSPICE.
>On the other hand, trying to do anything approaching full board simulation
>with HSPICE alone can be a problem (problem 1: Where do you get the SPICE
>models for the tlines auto-extracted from your layout) and Hyperlynx is
>pretty good at this.
>
>As far as the model conversion to IBIS, you might check with Mentor
>Consulting or Scott McMorrow at teraspeed.
>
>-----Original Message-----
>From: si-list-bounce@xxxxxxxxxxxxx
>[mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Naveen Reddy
>Sent: Friday, September 26, 2003 10:38 AM
>To: si-list@xxxxxxxxxxxxx
>Subject: [SI-LIST] HyperLynx vs Hspice
>
>
>Hi Everybody:
>I need to perform some high speed simulations (over 3GHz) for my
>backplane and I currently have the Mentor HyperLynx tool. I have run
>into a little problem. HyperLynx needs IBIS models for simulation
>purposes, whereas most of the vendors provide only spice models and not
>IBIS. Although HyperLynx can convert Spice models to IBIS, it does need
>a Spice simulator to do that.
>
>I am a little confused here and am hoping I can have these questions
>answered.
>
>1. Can I use just Hspice to perform all my high speed simulations or is
>HyperLynx a better tool for this application?
>2. Has anyone had experience with converting 3D spice models to IBIS?
>What are the tradeoffs?
>3. HyperLynx has three levels of licenses - regular, EXT and GHZ. Which
>one should I be using?
>
>Thanks in advance.
>
>-Naveen.
>
>
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