Gzeng, Sorry for the late response. There are two articles I know of which discuss this question. You can download them from the links provided by Mentor's web site: http://www.mentor.com/pcb/ibis_modeling.html?nav=3Dpcb_bs_highspeed&siteh= ead=3Dpcb_bs&navtabs=3Dpcb_bs_1:3,pcb_bs_2highspeed Scroll down and look for "Academic Articles" under "Articles, Presentations & Documents" section. Both papers are listed there, but the direct link to the second paper is: http://www.sigrity.com/papers/ectc96/DOectc96ibis.htm They basically say the same, but the problem with this approach is that they rely on a basic assumption. The assumption is that the scaling coefficients for the pulldown or pullup IV curves remain the same regardless of what R_fixture and V_fixture combinations you use to generate your waveforms. Having done some experiments I can tell you that in real life this is not completely true (but it is a good start). That is why the Cadence's user manual may say what it says, however, I am not in the position of verifying or clarifying that. Arpad Muranyi Intel Corporation =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D -----Original Message----- From: qzheng [mailto:qzheng@xxxxxxxxxxxxxxxx] Sent: Monday, February 24, 2003 7:55 PM To: si-list Subject: [SI-LIST] question about IBIS's V-T curve Scaleing ? Hello si-list Gurus , I have read some docs about how simulator using IBIS model to construce a behavior model. this question have discussed before and now i know V-T curve is used to scale V-I curve and regenerate a transient V-I curve. But when i reading Cadence's user manual( simref.pdf page:386 ) sth make me puzzle. there is a discussion about VT curves and switching , It is points out that switching coefficient does not uniquely fall out of VT curves and there are priori assumptions have to be made,and there are some model cases . I am difficult to understand this , what assumptions needed ? except using V-T curve or Ramp data , is there any other ways to scale V-I curve ? thanks in advance --=20 Best regards, qzheng mailto:qzheng@xxxxxxxxxxxxxxxx ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: =20 //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages=20 Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu =20 ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list 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