Subject: Re: [IBIS-Users] IBIS Models & Device Speed Grade
From: Ingraham, Andrew (a.ingraham@ieee.org)
Date: Mon Jul 21 2003 - 12:52:07 PDT
> Apart from doing lab measurement, are there any other
> ways of generating IBIS models for each device speed
> grade (slow, typical and fast)?
> I don't think Spice extraction can do this since speed
> grades are only determined after fabrication. (Please
> correct me if I'm wrong)
That depends. I have used SPICE models created well before fabrication,
that represented weak, typ, and strong process corners.
One could also argue that even Typical SPICE models are inaccurate (and
therefore unavailable) before fabrication. All are extrapolations based on
expectations, and all can be expected to change over time. A good fab house
should have some idea of what their process variations will be, based on
past history.
I have also seen suggestions to take the typical curves (or typical SPICE
model) and scale them by some percentage to get the weak/strong corners.
No, it isn't very scientific. But scaling a well developed process ought to
be reasonably predictable so that such extrapolations tend to work much of
the time. Still, exceptions happen.
Regards,
Andy
|------------------------------------------------------------------
|For help or to subscribe/unsubscribe, email majordomo@eda.org
|with just the appropriate command message(s) in the body:
|
| help
| subscribe ibis <optional e-mail address, if different>
| subscribe ibis-users <optional e-mail address, if different>
| unsubscribe ibis <optional e-mail address, if different>
| unsubscribe ibis-users <optional e-mail address, if different>
|
|or email a written request to ibis-request@eda.org.
|
|IBIS reflector archives exist under:
|
| http://www.eda.org/pub/ibis/email_archive/ Recent
| http://www.eda.org/pub/ibis/users_archive/ Recent
| http://www.eda.org/pub/ibis/email/ E-mail since 1993
This archive was generated by hypermail 2b28 : Mon Jul 21 2003 - 13:16:12 PDT