Arpad and Panch, In the document referenced, there are a number of restrictions on the use of the LVDS IBIS model. For example, it states that for accuracy, the same VDDQ and the same loading conditions must be present as when the model was created. This is a rather severe restriction, as it practically defeats the intent of a simulation model (i.e. to predict performance under uncertain operating conditions). I believe the fundamental problem is that IBIS assumes a specific Output topology (i.e. pull-up and pull-down elements, with drive strengths specified as i vs. v data). If the actual circuit being modeling has a fundamentally different topology, such as a controlled current source being steered from one output pin to the other, then it will be very difficult to match results under widely varying operating conditions. Beyond matching the basic Output electrical characteristics, there is additional complexity in today's multi-gigabit I/O designs that must be included for accurate system performance evaluation. This includes pre-emphasis control logic, settable or adaptive equalization characteristics, digitally controlled termination impedance, etc. Even the PLL tracking capability of the Clock and Data Recovery (CDR) System has a significant impact on overall system performance (i.e. jitter and BER), and should be included in the system level analysis. The need to handle these types of complex I/O buffer behaviors is what drove the recent extension to the IBIS Standard (Bird 75). The IBIS Committee wisely discerned that the rapid advancement of I/O technology could not be dealt with via piecemeal behavioral extensions to the IBIS Specification. So they opened the doors to existing hardware modeling standards: Currently SPICE and VHDL-AMS. SPICE, of course, is a well known and established format for describing any general circuit structure. VHDL-AMS is a newer analog and mixed-signal modeling standard (IEEE 1076.1), specifically designed to meet complex behavioral modeling requirements, such as those of multi-gigabit I/O technology. Because it provides "behavioral modeling", like IBIS, it protects the vendor's circuit structure "IP", and also simulates very fast. Its capability to model all of the advanced features described above (i.e. current mode signaling, pre-emphasis and equalization, CDR, etc.) has been demonstrated. http://www.mentor.com/systemvision/high_speed/index.html <http://www.mentor.com/systemvision/high_speed/index.html> Although there is somewhat limited support for this technology today, that is changing quickly. Many IC vendors have expressed strong interesting in using VHDL-AMS for capturing and distributing their current and next generation multi-gigabit I/O technology, and several EDA tool vendors have or are developing capability to support this format. Because it is a technology that perfectly addresses an important and growing need, I expect its widespread adoption to come rapidly. Perhaps this is similar to the early days of IBIS? Mike -----Original Message----- From: Muranyi, Arpad [mailto:arpad.muranyi@xxxxxxxxx] Sent: Monday, July 21, 2003 3:35 PM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: Behavioral modeling It can be done (if you know what you are doing)... Have you seen this presentation? =20 http://www.eda.org/pub/ibis/summits/jun03b/haller.pdf =20 Arpad =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: Panch Chandrasekaran [mailto:panch_si@xxxxxxxxx] Sent: Monday, July 21, 2003 3:12 PM To: Muranyi, Arpad; si-list@xxxxxxxxxxxxx Subject: [SI-LIST] Re: Behavioral modeling Arpad, Thanks for your reply. There is a general feeling that IBIS is not very = accurate for multi-gigabit/s data streams and it is a pain to = incorporate features like pre-emphasis etc. Any thoughts on this.=20 =20 Panch "Muranyi, Arpad" <arpad.muranyi@xxxxxxxxx> wrote: Have you checked into IBIS modeling? http://www.eigroup.org/ibis/ibis.htm Arpad =3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D= 3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D =3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D=3D3D -----Original Message----- From: Panch Chandrasekaran [mailto:panch_si@xxxxxxxxx] Sent: Monday, July 21, 2003 11:22 AM To: si-list@xxxxxxxxxxxxx Cc: panch_si@xxxxxxxxx Subject: [SI-LIST] Behavioral modeling All, What is a good way to do behavioral modeling? Running SPICE for high =3D speed simulations ( 3 - 4 Gbps) can be very time consuming especially = =3D with backplane,via, connector models etc. I have heard that VHDL AMS and = =3D Cadence's DML are options that can used with their tools. Is there a =3D simpler way to do it with reasonable accuracy? Stuff that can be imported into SPICE tools and that will save on =3D simulation times. =3D20 Thanks for your thoughts. =3D20 Panch Chandrasekaran --------------------------------- Do you Yahoo!? SBC Yahoo! DSL - Now only $29.95 per month! ------------------------------------------------------------------ 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: =3D20 //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages=3D20 Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu =3D20 ------------------------------------------------------------------ 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 --------------------------------- Do you Yahoo!? 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DSL - Now only $29.95 per month! ------------------------------------------------------------------ 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 ------------------------------------------------------------------ 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