Thanks a lots for the impressive answers. I have a further quetions here... If the Ccomp value obtaining from Spice model (or from lab measurements) is put in the IBIS model and it is found that the IBIS simulation waveforms are not correlated to Spice model sim results, should we fine tune the Ccomp value to make them correlate? Thanks again for the help. -Lee >From: "Muranyi, Arpad" <arpad.muranyi@intel.com> >To: <ibis-users@eda.org> >Subject: RE: [IBIS-Users] C_Comp >Date: Wed, 2 Mar 2005 08:46:10 -0800 > >Tom, > >I think we are both correct. It just depends on what we >mean by our words. Does "include C_comp effect" mean >included in the chip from which the measurement is >made, or included in the data that you get in the >measurement? You are probably talking about the first, >while I was talking about the second. > >Arpad >======================================================== > >-----Original Message----- >From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On Behalf >Of Todd Westerhoff (twesterh) >Sent: Wednesday, March 02, 2005 4:02 AM >To: ibis-users@eda.org >Subject: RE: [IBIS-Users] C_Comp > > >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 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 _________________________________________________________________ Block pop-up ads with MSN Toolbar. http://toolbar.msn.com.my/ |------------------------------------------------------------------ |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 16:28:05 2005
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