Tariq, Thank you very much for your detailed response. I learned a great amount from it. I have already generated the IBIS2XTK models and they are working well but before you replied I wondered if it would be worth the effort of generating the SPI2MOD models. I will probably go ahead and generate them for the education, but it is very good to hear and learn from your experiences. I certainly appreciate your reply. Thank You Again, Adam Tambone ABOUJEYAB@xxxxxxx@freelists.org on 06/20/2001 03:01:03 PM Please respond to si-list@xxxxxxxxxxxxx Sent by: si-list-bounce@xxxxxxxxxxxxx To: si-list@xxxxxxxxxxxxx cc: ABOUJEYAB@xxxxxxx Subject: [SI-LIST] Re: IBIS2XTK v. SPI2MOD Hi Adam... First of all, if an ibis model is available it's easier to generate xtk files from IBIS2XTK, since you don't have to worry about producing spice output files to use with SPI2MOD. As far as accuracy, from my experience I found them to be very close. Both IBIS2XTK and SPI2MOD do not like non-monotonicity in the VT curves and will try to straighten this out. SPI2MOD doesn't like non-monotinicity in the VI curve, whereas IBIS2XTK doesn't like it in the following sums: HIGH+SHUNT and LOW+SHUNT. That's okay, because in one of my previous simulations I compared the original spice simulation (which has non- monotonicity) with xtk simulation (monotonicity is straightened) and the results were very close. That means in real life monotonicity doesn't affect you very much because it will be reduced by introducing package capacitance and all the inductances on the board. Another thing that the XTK manual mentiones is that SPI2MOD is designed to be used with enhanced models excluding the multi-VI devices. So if your driver has two stages of pull-ups and pull-downs, or a more complex design then SPI2MOD as it is doesn't produce accurate models. You have to run separate SPICE simulation for individual stages and becomes complicated, and I don't know how to do that. In short, if you have ibis models and you trust them, then use them. Also, I don't think there is any special treatment for differential models. If somone or someones disagree with me that's okay, I'm still learning and would appreciate any correction or addition to my assesment. Thanks,. Tariq Abou-Jeyab ------------------------------------------------------------------ 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 Old 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 Old list archives are viewable at: http://www.qsl.net/wb6tpu