Adam Tambone Wrote: > > 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 > Hi Adam: Thanks for your comments, and as you stated non-monotonicities are allowed and exist in I-V waveforms. Many simulator programs sum the POWER Clamp and Pullup ( also GND Clamp and Pulldown) currents to produce monotonic curves (for tristate buffers). I have also read that some simulators crash due to non-monotonicity of the I-V curves. In any case, when using an IBIS model (particularly for the first time) it is advantageous to examine the I-V curves via methods described earlier. Knowing the model (and the simulator) greatly helps to ascertain whether the non-monotonicites are negligible, or can cause significant simulation inaccuracies. An article by Bob Ross, "Practical Issues With IBIS Models", available on the ANSI/EIA web site, contains a good discussion of the monotonicity topic. Best Regards, Abe Riazi ServerWorks ------------------------------------------------------------------ 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