Subject: RE: [IBIS-Users] Waveform mismatch question
From: Muranyi, Arpad (arpad.muranyi@intel.com)
Date: Thu Jan 23 2003 - 11:51:06 PST
John,
Theoretically there should be no mismatch messages. If there
are, something is wrong. However, this is an area where the
parser was also corrected numerous times, so first I would
suggest that you get the latest version if you don't have it
yet.
If you still get this message, than you need to check your
model data. What this means is that the IV curves of your
model would give you different waveform voltages than what
your waveform tables have. It all boils down to Ohm's law.
If the model has such relatively large mismatches, Ohm's
law is violated somewhere. Depending on the simulator's
algorithms, this may or may not be a problem, but then you
don't know what they did to make it work either.
Arpad Muranyi
Intel Corporation
=============================================================
-----Original Message-----
From: Angulo, John [mailto:john_angulo@mentorg.com]
Sent: Thursday, January 23, 2003 11:10 AM
To: 'ibis-users@eda.org'
Subject: [IBIS-Users] Waveform mismatch question
The following is posted on behalf of John Phillippe at Motorola. Please send any private replies to john.phillippe@motorola.com only.
--------------------------------------------------
Ibis Guru's,
I get quite a few waveform mismatches between the rising/falling
edges and the I/V curves like the one shown below.
WARNING - Model pad_26v_fast: The [Falling Waveform]
with [R_fixture]=50 Ohms and [V_fixture_max]=0V
has MAX column DC endpoints of 0.05V and 1.75v, but
an equivalent load applied to the model's I-V tables yields
different voltages ( 0.16V and 1.91V),
a difference of 6.66% and 8.94%, respectively.
I'm curious if this is a common problem, or if there are some simple
solutions to get everything to match up. I check the waveforms and set
the sim time long enough to make sure the waveforms are stable. Any
help/suggestions would be greatly appreciated.
-- John Phillippe SPS, 32 Bit Embedded Controller Division, IC Creation Motorola - 512-895-1835 Austin, TX - john.phillippe@motorola.com |------------------------------------------------------------------ |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 |------------------------------------------------------------------ |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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