Andy, (I got two of these messages). You are making a good point, but the way I understood this story was that if you didn't define those optional clamp reference nodes, the current was automatically coming out of the pullup and pulldown reference nodes, just as if the clamp reference would have been shorted to them. Now, in the earlier version of HSPICE there was a bug in this, but I thought that was fixed a long time ago, though I didn't check it lately. I got too used to defining all nodes every time I use it... Arpad ======================================================== -----Original Message----- From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On Behalf Of Andrew Ingraham Sent: Saturday, April 02, 2005 5:34 AM To: ibis-users@eda.org Subject: Re: [IBIS-Users] ODT topics Hmmm, my mail doesn't seem to be reaching eda.org. Here is try # 3: > "My question would be: what are simulators (e.g. HSPICE) really doing with > IBIS models ... > The clamp I-V tables are always present in the simulation, and > the pullup and pulldown I-V tables are switched on/off as the > buffer is driving high/low. The end result is that the currents > of the pullup or pulldown I-V tables are added together with > the clamps. Well actually, ... Sorry to nit-pick, but in HSPICE the clamps are not necessarily always there. The end-user who puts an IBIS model in his simulation needs to make sure to include ALL the optional element nodes. If he leaves the optional nodes out, HSPICE has this nasty feature (it is really intended as a feature, not a bug) that the clamp I-V tables are omitted. Once those nodes are included in the netlist, then Arpad's statement above is correct. 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 1993Received on Mon Apr 4 09:51:12 2005
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