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 1993Received on Mon Jan 15 08:38:56 2007
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