Lets try some simple evaluation first. 1, Have you done any analysis of your tables? Have you plotted the VT and IV curves? Do they look reasonable? Do you know what reasonable is for this buffer? Do the transitions complete? Is there sufficient number of points in all curves? Are the IV curves what you expect? If the buffer is a CMOS totem pole does the pullup have zero current at Vdd? Do you have reasonable clamp curves? 2, do you find it funny that you have a buffer that has a 3.6 volt supply (I assume that because your termination voltage V_fixtrue_max is usually Vdd) but your IV curve load line is predicting 4.4V? 3, Is your setup for simulation correct? Do you have the proper supplies to the proper nodes? Tom Dagostino Teraspeed Labs 13610 SW Harness Lane Beaverton, OR 97008 503-430-1065 http://www.teraspeed.com tom@teraspeed.com Teraspeed Consulting Group LLC 121 North River Drive Narragansett, RI 02882 401-284-1827 Teraspeed is the registered service mark of Teraspeed Consulting Group LLC -----Original Message----- From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org]On Behalf Of lgreen Sent: Friday, May 20, 2005 10:51 AM To: 'Vivek Kumar Sundriyal'; ibis-users@eda.org; owner-ibis-users@eda.org Subject: RE: [IBIS-Users] problem with the rising and falling waveforms Hi, Vivek, Two items: 1) The V-t curves should have "zero slope" at both ends. 2) There I-V tables need a small enough step size so the linear interpolation is accurate where the load line crosses. Either (or both) of those could cause the parser report that you are seeing. Drawing a load line on the I-V table can help identify the problem. Another thought: Is 100 Ohms the usual transmission line impedance for designs using this device? Is this same resistance used for the [Ramp] section? Best regards, Lynne "IBIS training when you need it, where you need it." Dr. Lynne Green Green Streak Programs http://www.greenstreakprograms.com 425-788-0412 lgreen22@mindspring.com -----Original Message----- From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On Behalf Of Vivek Kumar Sundriyal Sent: Friday, May 20, 2005 3:22 AM To: ibis-users@eda.org; owner-ibis-users@eda.org Subject: [IBIS-Users] problem with the rising and falling waveforms Hi , On running the IBISCHK4 on a generated IBIS model, I get the following error : ERROR - Model K3B07LG24Q7_QQ60: The [Rising Waveform] with [R_fixture]=100 Ohms and [V_fixture_max]=0V has MAX column DC endpoints of 0.00V and 3.46v, but an equivalent load applied to the model's I-V tables yields different voltages ( 0.00V and 4.23V), a difference of 0.03% and 18.33%, respectively. ERROR - Model K3B07LG24Q7_QQ60: The [Rising Waveform] with [R_fixture]=100 Ohms and [V_fixture_max]=3.6V has MAX column DC endpoints of 0.11V and 3.60v, but an equivalent load applied to the model's I-V tables yields different voltages ( 0.11V and 4.40V), a difference of 0.04% and 18.69%, respectively. Can anyone guide me on the cause of this error ? And how can I get over with it ? Thanks , Vivek |------------------------------------------------------------------ |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 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 May 20 11:12:31 2005
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