Date: Thu Oct 22 2009 - 09:21:53 PDT
Kobi Is there a series resistor model in the file that could be the termination you are looking for? Many times we use the series resistor feature of IBIS to model input terminations. This works much better than putting those characteristics in the ground or power clamp. In many cases the termination can float but with the termination imbedded in the clamp curve you are stuck with a fixed set of IV characteristics. Tom Dagostino Teraspeed(R) Labs 13610 SW Harness Lane Beaverton, OR 97008 503-430-1065 503-430-1285 FAX tom@teraspeed.com www.teraspeed.com Teraspeed Consulting Group LLC 121 North River Drive Narragansett, RI 02882 401-284-1827 From: owner-ibis-users@server.eda.org [mailto:owner-ibis-users@server.eda.org] On Behalf Of Kobi Pinhas Sent: Thursday, October 22, 2009 8:57 AM To: ibis-users@server.eda.org Subject: [IBIS-Users] Clamp graphs issue. Hi all. I have some conceptual issue. The next graph represents gnd clamp of an input model of a memory with 120 ohm ODT This is model of a famous company which I download: I don't understand how it is possible that the current is zero fot V> -0.5V. The meaning of ODT is resistor that connected from the input to the gnd. So for this range (when V>-0.5V) I was expecting to see linear current with a slope that equal to the resistor. For example when I simulated gnd clamp of an input buffer with 50 ohm ODT I received the next plot: You can see that the plot is liner for V> -0.5V as expected. I looked in a lot of ibis file and I never saw common behavior. So I guess that maybe I am doing something wrong. I will be glad to hear your comments. Thanks a lot. Kobi. -- This message has been scanned for viruses and dangerous content by <http://www.mailscanner.info/> MailScanner, and is believed to be clean. -- 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 1993
