Ed, Unless I'm mistaken, 0-1V is the designated swing for the input signals to an IBIS buffer. Your results are interesting; I've never tried using anything other than 0-1V. Todd. Todd Westerhoff High Speed Design Specialist Cisco Systems 1414 Massachusetts Ave - Boxboro, MA - 01719 email:twesterh@xxxxxxxxx ph: 978-936-2149 ============================================ "When did the choices get so hard, with so much more at stake? Life gets mighty precious when there's less of it to waste" - Bonnie Raitt, "Nick of Time" -----Original Message----- From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]On Behalf Of Ed Sayre III Sent: Wednesday, February 12, 2003 6:16 PM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] IBIS I/O model in HSPICE question Hi All, I am running an IBIS I/O model in HSPICE and have see some very strange results dependant on the input voltage swing. I am using the Ibis I/O in the driver mode, driving a simple resistor load and another sim driving a match terminated 25 Ohm tline and resistor load. According to Page 18-43 of the 2000.2 manual either a 0-1V swing can be used for the input or a typical 0-3.3V input swing can be used. When I compare the outputs of the I/O the two input level I find they are significantly different in wave shape and peak overshoot. The 3.3V swing gives significant overshoot spikes on the output node of the I/O model. When I look at the output current (very clean and controlled, it would seem that ohms law is not observed, this doesn't make sense. Does anyone have an idea of why this is occurring, and is it typical of Ibis model outputs run in HSPICE to behave differently dependant on what voltage swing is applied to the input node of the driver??? BTW, I am in direct contact with the vendor so I am interested in seeing if people have seen this and if it is a model or an IBIS/HSPICE issue. Thanks in advance, -Ed ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ NORTH EAST SYSTEMS ASSOCIATES, INC ------------------------------------- "High Performance Engineering & Design" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Dr. Edward Sayre 3rd e-mail: esayre3@xxxxxxxx NESA, Inc. http://www.nesa.com/ 5 Lan Drive, Suite 200 Tel +1.978.392-8787 x 218 Westford, MA 01886 USA Fax +1.978.392-8686 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ------------------------------------------------------------------ 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 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 ------------------------------------------------------------------ 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 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