Subject: [IBIS-Users] Re: [IBIS] ECL Termination Voltage Question
From: Bob Ross (bob@teraspeed.com)
Date: Thu Jan 15 2004 - 17:01:22 PST
Hi Mike:
[Ramp] is required for the IBIS compliance even when
V-T tables are provided. Most EDA tools rely on
this requirement to make use of the ramp information.
When V-T tables were added to IBIS we decided to continue
requiring [Ramp] so that users had a backup method to
use the model for EDA tools that had not yet implemented
the V-T support. But we also chose to not add anymore
features to [Ramp] because a "full featured" [Ramp] would
still be less accurate than the corresponding V-T
table information.
My other responses are in your text.
Bob
Michael Sachtjen wrote:
> Bob,
>
> You have a lot more experience with IBIS than I, but
> your statement "[Ramp] is not used when you have V-T
> tables" seem misleading. It's my understanding that
> the simulators (Cadence at least) need to know the
> switching time and dV from the [Ramp] even though
> waveforms are provided? Please correct me if I'm
> wrong.
You are correct. Most EDA tools still used the
[Ramp] information because it is a required keyword.
>
> I don't mean to confuse the issue; I know this thread
> is not about the Ramp. I only want to clearify that
> you can't just put 1/1 in for the ramp if you have V-T
> tables.
You are correct. Even if V-T tables are provided, the
[Ramp] information still needs to be realistic.
>
> - Mike
>
[.... deleted messages ....]
-- Bob Ross Teraspeed Consulting Group LLC Teraspeed Consulting Group LLC 2926 SE Yamhill St. Device Modeling Division Portland, OR 97214 13610 SW Harness Lane 503-239-5536 Beaverton, OR 97008 http://www.teraspeed.com 503-430-1065 bob@teraspeed.com 503-246-8048 Direct|------------------------------------------------------------------ |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
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