Just a word of caution. It is true that currents in the uA and nA range may not put a big dent into your normal signal integrity simulation results (when buffers are driving and receiving). However, there are some folks out there who may be interested in how the bus floats, i.e. what will the voltage on a bus be when all buffers are in the high impedance state. In this case even these small currents become important. It is the model maker's choice whether they want to make their IBIS model accurate enough for such purposes by making sure that the clamp tables do have these currents in them. Arpad Muranyi Intel Corporation ----------------------------------------------------------- -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] = On Behalf Of Tom Dagostino Sent: Thursday, December 16, 2004 11:39 AM To: Rohan.Hubli@xxxxxxxxxxxxxxxx; a.ingraham@xxxxxxxx; = si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: Strange Gnd Clamp V-I curve when generating IBIS=20 Most datasheets will spec input leakage currents at less than 10 uA. = This is supposed to account for the leakage currents. If you have less than = that I wouldn't worry about it. 10 uA and 50 Ohms gives 0.5 mV of IR drop assuming you have a 50 Ohm termination in the system. If you don't like seeing that current you can zero it out and not really change the model. Tom Dagostino Teraspeed Consulting Group LLC 503-430-1065 tom@xxxxxxxxxxxxx www.teraspeed.com ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu