Abe and SignalDude, Those are good points but I would like to add to the discussion regarding non-monotonicity and discontinuities in the I-V curves. Non- monotonicities can and do exist in I-V curves. These non-monotonicities can be valid and accurate representations of the device being modeled especially since they range over a broad voltage domain that goes beyond the recommended operating limits of the device i.e. -Vcc to 2Vcc. Simulators have difficulty processing the non-monotonicities, but this does not make the curves invalid. Best Regards, Adam Tambone "abe riazi" <ariazi@xxxxxxxxxxxxxxx>@freelists.org on 08/21/2001 09:16:13 PM Please respond to ariazi@xxxxxxxxxxxxxxx Sent by: si-list-bounce@xxxxxxxxxxxxx To: "'si-list@xxxxxxxxxxxxx'" <si-list@xxxxxxxxxxxxx> cc: Subject: [SI-LIST] Re: IBIS model. Signalguy Wrote: Also how can I make sure the values under the pullup and pull down = curves are correct.=20 regards, Signalguy. Hi: Some of the steps related to verification of the Pullup and Pulldown = curves consist of: 1. Evaluation of the I-V curves for monotonic behavior and lack of = discontinuities. 2. Examination of the Pullup and Pulldown tables for origin (e.g. both V = and I approximately 0 ) crossing. 3. Inspection of the voltage range, and polarity sign of the current. Let us briefly explore the meaning of these tasks. Existence of monotonicity (or lack thereof) for the I-V curves (as well = as for V-T waveforms) can be checked using a program such as the = HyperLynx Visual IBIS Editor. Executing the IBIS golden parser can also = produce valuable information about accuracy of the model. Each I-V table contains four columns namely Voltage, I(typ), I(min), and = I(max). Nonetheless, a model may lack I(min) and I(max) data, since the = IBIS specs require data only for the typical column. Regarding the voltage values; the I-V tables for many buffer models are = generated based on sweep voltage range of -Vdd to 2 * Vdd; however, the = Pullup and POWER Clamp data are Vdd or Vcc relative (e.g. voltage = entries in the table represent Vcc - V output.). The current polarity = also deserves attention as positive sign implies current flowing into = the part (sink), and vice versa. Furthermore, the Pullup and Pulldown data can be readily exported to an = Excel Spreadsheet for additional analyses. Certain model problems prove simple to fix, whereas complicated = deficiencies usually necessitate contacting the model creator. I hope you find this information helpful. Best Regards, Abe Riazi ServerWorks =20 =00 ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field 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 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