Fabino The check that is giving you a problem is a consistency check. It is determining if the VT waveforms and the IV curves are consistent in both the load resistance present and termination voltage used to simulate the VT waveforms. You can look at the problem this way. The output impedance of the buffer at a given voltage is a resistance Ro. This resistance is non linear and is described by the IV curve. When a load Rl is placed on the output there is a voltage divider generated. This output voltage is checked against the VT curves endpoints. There are several different things that can cause there to be endpoint mismatch. First, the load used to extract the VT curves is not the same as the one in the check. Remember the load has two part, Resistance and termination voltage. Second there may be issues with the IV extractions. Third, there may be double counting of the clamp IV curves. If there is some kind of resistive termination or pullup or pulldown in the buffer this may not have been correctly accounted for. Etc. Shot gunning the solution by changing the termination resistance may or may not fix the problem. You need to understand the cause of the problem is fix that. Tom Dagostino Teraspeed(R) Labs 13610 SW Harness Lane Beaverton, OR 97008 503-430-1065 tom@teraspeed.com www.teraspeed.com Teraspeed Consulting Group LLC 121 North River Drive Narragansett, RI 02882 401-284-1827 -----Original Message----- From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org]On Behalf Of Fabio BRINA Sent: Friday, January 20, 2006 6:56 AM To: ibis-users; ibis Subject: [IBIS-Users] WARNING Endpoint Hi IBIS experts, when I check my IBIS model I optain these warning: WARNING - Model 'mod_out': TYP AC Rising Endpoints ( 0.00V, 4.97V) not within 0.099V (2%) of ( 3.11V, 3.94V) on VI curves for 1000 Ohms to 0V WARNING - Model 'mod_out': TYP AC Falling Endpoints ( 0.02V, 5.00V) not within 0.100V (2%) of ( 3.14V, 3.96V) on VI curves for 1000 Ohms to 5V I know what it means, but I don't know if I have to modify the R_fixture to eliminate it ( I fix R_fix=1k from the datasheet ). morever in some IBIS editor this Warning became an Error ! so I don't know if is an acceptable Warning. ( I use s2ibis2 v.2.1 ) What do you think about? many thanks Another type of question: About IBIS Summit ( DATE 06 ), there is an expiry date to register on them? thanks again. Fabio. |------------------------------------------------------------------ |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 Fri Jan 20 09:44:33 2006
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