[SI-LIST] Re: IBIS Model Quality (or lack thereof)
- From: "Jeremy Plunkett" <jeremy@xxxxxxxxxxxxxxx>
- To: twester@xxxxxxxxxxx, si-list@xxxxxxxxxxxxx
- Date: Tue, 26 Mar 2002 12:59:24 -0800
Todd,
At a minimum, ServerWorks' IBIS models are validated prior to release by:
1) Syntax check using Hyperlynx Visual IBIS editor.
2) Correlation to the original spice deck waveforms using the hspice B
element. In the past, the degree of correlation has not been quantified
because typically it is all-or-nothing; either the waveforms are a 99%
match point-for-point (inspected visually in Awaves), or there was some
serious problem in the conversion that needs to be corrected. Occasional=
ly,
there are correlation issues caused by limitations of the IBIS format or =
the
extraction process; in these cases we determine a work-around such as
changing which model data is included in which curves, adding a submodel,
etc. When a standardized method of correlating the IBIS results to spice=
is
determined by the IBIS qualification committee I would be happy to includ=
e
it in our correlation process, provided it can be accomplished either usi=
ng
hspice MEASURE functions such as DERIVATIVE, ERR, etc, or using a softwar=
e
utility that can import the waveforms from a text file.
After the initial release, our models are converted to various other form=
ats
in-house and by our customers, which can sometimes bring out correlation
issues between different simulators or problems with the model conversion
processes. Also, at some point after the initial release the models are
correlated with silicon and corrected if necessary.
Serverworks has the same situation that Adam Tambone mentioned in his
posting, a large library of existing IBIS models(though not as large as
Fairchild's), not all of which were generated or correlated to the same
level of scrupulousness that we currently follow. In our case most of th=
ese
parts are no longer being used in new designs, so fixing problems in the
IBIS models is a low priority, however we will address any issues with an=
y
of our models as customers request it.
To any customers who may be reading this: feel free to address any feedba=
ck
regarding ServerWorks' IBIS models directly to me (preferably privately, =
not
to the whole SI list). However, please address requests to receive the
models in the 1st place to our marketing dept.
Jeremy
|>--/\/\/--((((((((()--|>
Jeremy Plunkett
Signal Integrity Engineer
ServerWorks Corp
www.serverworks.com
|>--/\/\/--((((((((()--|>
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx
[mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Todd Westerhoff
Sent: Monday, March 25, 2002 12:59 PM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] IBIS Model Quality (or lack thereof)
Hi all,
We have been doing a lot of comparisons between IBIS and HSpice models
lately, with a lot of less-than-satisfactory results.
I have an open question for the semiconductor suppliers among us:
What testing is performed after an IBIS model is created, to ensure that =
the
completed model behaves as expected? I'm interested in responses from
vendors that actually SIMULATE the IBIS model before distributing it for
customer use. It looks to me as though many of the models I've received
were never used in a simulation before being released ... and, as a
potential customer, I find that quite disheartening.
So the question is - what processes are being used to test IBIS models an=
d
ensure they function properly before their release to customers?
As always, replies both on and off the list are greatly appreciated.
Todd.
Todd Westerhoff
Signal Integrity Engineer
Hammerhead Networks
5 Federal Street - Billerica, MA - 01821
email:twester@xxxxxxxxxxx - ph: 978-671-5084
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
"I=92m starting With the man in the mirror
I=92m asking him to change his ways
And no message could have been any clearer
If you wanna make the world a better place
Take a look at yourself, and then make a change"
- "Man in the Mirror", Michael Jackson
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List archives are viewable at:
//www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List archives are viewable at:
//www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
