RE: [IBIS-Users] RE: [IBIS] Ibis open drain strange behaviour

I would like to chime in about "frequency dependence" and
"over clocking".  Even though over clocking is usually 
achieved by cranking up the frequency of the stimulus, 
it not the only way to achieve that.  You can also
get that effect by changing the duty cycle so that the
short half of the cycle becomes shorter in duration than
the length of the V-t table in the IBIS file.

On the other hand, when I think of frequency, I usually
think of it more in terms of frequency domain analysis.
What does the model do with the higher harmonic components
of the signals?  From this perspective legacy IBIS does
not have the capability to describe frequency dependent
buffer behavior, because the I-V curves yield a constant
impedance at all frequencies, and C_comp is also a constant
for all frequencies.  In real life there are all kinds of
variations with respect to frequency.

Having said all this, I prefer to use the term "frequency
dependence" for the latter, and "over clocking" for the
former topic.

Arpad
===========================================================
-----Original Message-----
From: Radovan.Vuletic@qimonda.com [mailto:Radovan.Vuletic@qimonda.com] 
Sent: Monday, January 15, 2007 4:11 AM
To: twesterh@sisoft.com; ibis@eda-stds.org; ibis-users@eda.org
Subject: RE: [IBIS] Ibis open drain strange behaviour

Hi Tod,

I believe that you have started/mentioned now 2 different topics, that
according to my opinion should be separated:
1.) correlation between HSpice and IBIS models and
2.) "overclocking of IBIS models" as some prefer to call it or
"frequency dependant IBIS models" (sounds very funny) as others prefer
to call it.

...
...
...

Regards,
Radovan

-- 
This message has been scanned for viruses and
dangerous content by MailScanner, and is
believed to be clean.


--------------------------------------------------------------------
|For help or to subscribe/unsubscribe, e-mail majordomo@eda-stds.org
|with 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 e-mail a request to ibis-request@eda-stds.org.
|
|IBIS reflector archives exist under:
|
|  http://www.eda-stds.org/pub/ibis/email_archive/ Recent
|  http://www.eda-stds.org/pub/ibis/users_archive/ Recent
|  http://www.eda-stds.org/pub/ibis/email/         E-mail since 1993