Arpad, Is that true? I'm not trying to split hairs here, but I'd say that the VI curves are generated from a Spice model that includes C_Comp effects. Because the VI curves are derived from a DC sweep, however, the effect of C_Comp drops out. The point I'm trying to make - people don't need to "remove" C_Comp from a Spice model to derive an IBIS model. Todd. Todd Westerhoff High Speed Design Group Manager Cisco Systems 1414 Massachusetts Ave - Boxboro, MA - 01719 email:twesterh@cisco.com ph: 978-936-2149 ============================================ "Always do right. This will gratify some people and astonish the rest." - Mark Twain -----Original Message----- From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On Behalf Of Muranyi, Arpad Sent: Wednesday, March 02, 2005 1:34 AM To: ibis-users@eda.org Subject: RE: [IBIS-Users] C_Comp Lee, The IBIS model's IV curve which determines its impedance does not include any C_comp effects. The Vt curves which are used to turn on and off the IV curves do include the C_comp effect in their shape, but they do not effect the DC nature of the IV curves. Therefore we do need to add a capacitor to account for the capacitive nature of the drivers (or receivers). As stated in another response, this is necessary for getting the correct reflections in the simulations when a wave hits the model. Arpad Muranyi Intel Corporation ------------------------------------------------------------ -----Original Message----- From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On Behalf Of lee yang Sent: Tuesday, March 01, 2005 8:58 PM To: ibis-users@eda.org Subject: [IBIS-Users] C_Comp Hi, Since the C_Comp effect is already embedded in the Spice model, hence, the generation of IBIS model automatically includes the effect of it. I am wondering, since the C_Comp effect is already included in the IBIS model, why do we still need to put it in the IBIS file? Why it is so important? Thanks a lot. -Lee _________________________________________________________________ Get an advanced look at the new version of MSN Messenger. http://messenger.msn.com.my/Beta/Default.aspx |------------------------------------------------------------------ |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 Wed Mar 2 04:02:28 2005
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