But it could be a problem with the way the IBIS model was made. Vinayak, have you tested your IBIS model in any other simulators? I once had a model that worked in Cadence tools, but oscillated with HSPICE. I had to add some extra data points in the VI data to stop the oscillations. Aubrey Sparkman Enterprise Engineering Signal Integrity Team Dell, Inc. Aubrey_Sparkman@Dell.com (512) 723-3592 -----Original Message----- From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On Behalf Of Andrew Ingraham Sent: Wednesday, January 04, 2006 11:31 AM To: ibis-users@eda.org; ibis@eda.org Subject: [IBIS-Users] Re: hspice vs IBIS model correlation at different capacitive loads > I think he is saying that the oscillations happen because of the > feedback in the buffer is trying to settle to a steady state > condition. > > If so, legacy IBIS can not model your buffer, since there are no > provisions for describing feedback. Yes. Although it depends on the feedback. Linear negative feedback, such as used on op-amps to reduce output impedance, should work OK, I think. It's probably also possible that some forms of feedback to reduce variations in drive strength (for example), ought to be somewhat compatible with conventional IBIS. But things like positive feedback to give hysteresis, don't play well in IBIS. 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 |------------------------------------------------------------------ |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 1993Received on Wed Jan 4 09:38:18 2006
This archive was generated by hypermail 2.1.8 : Wed Jan 04 2006 - 09:39:23 PST