Zhiping, Point taken. And like I said before, I've got IBIS like IO model working with SSO model since 1997, I got a lot of help from some very smart people and they are proud of their work. That said, every year or so I hear this thread in SI-list about SSO, package noise and how everyone is working on a committee to address this issue. In the mean time, a lot of people have designed and analyzed successfully with other methods and tools outside of IBIS. At certain point of time, one has to look himself in the mirror and ask the question, "am I chasing the right solution while someone is passing me by with a different approach ?" And vice versa to myself, I have to ask, "am I critizing the wrong tool while they can actually address the problem I am pointing finger at ?" I can't answer the first question for anyone but I have to address the second question myself. That's lead me to my work in 97 and I still believe I drew the correct conclusion then and now. It has been seven years since. Did the wheel move in the industry yet ? Like I said before, SSO is something people have done since the 70's or 80's with SPICE. Why do you need to reinvent the wheel when you don't even know what your wheel looks like and have to keep using terms like "could be correctly modeled and solved in the future". What about now ? How come other people can solve it but you can't ? I can't answer the above questions for you. All I can do is take care of my own designs and whoever employ me and that's not an easy task for an average engineer like me. And may be, just may be, we should quit arguing about this and get the industry to hand out encrypted SPICE and package models instead. Let's try it. It may just work like I advertise. But until the day the customer side is united, it ain't going to happen. And as long as you have this hope of some committee is going to hand you your solution, it will happen next year, followed by the next and the next..... So while you are at it, may I suggest some other BIRD committees to address issues like behavioral receivers to handle sample and hold receivers, multi-stage equalization receivers, active feedback receivers or hybrid differential/single ended receivers etc. I have seen them all and I have yet to see any committee form to address that. And you would like to reply me with "could be correctly modeled and solved in the future", again ? I don't know, they are in current shipping products. -----Original Message----- From: Zhiping Yang To: Chris.Cheng@xxxxxxxxxxxx Cc: si-list@xxxxxxxxxxxxx Sent: 12/28/2004 10:24 PM Subject: Re: [SI-LIST] Re: Article discussion on bad packages Hi Chris, I have watched this topic for a while. There are a lot of valuable comments from the SI experts. I agree with you that existing IBIS model is not accurate and correct for SSO type analysis, but that does not mean there is no solution to solve the SSO problem by using behavior I/O models. At least, a proposed RBF behavior model from Prof. Canavero showed good results for SSO simulations. For the IBIS model, I think we already know the problems or shortcomings why it is not good for SSO simulation. Recently we (Cisco SI engineers) submitted a IBIS BIRD (BIRD95) to address this issue. I have to admit that our current proposal may not completely solve this problem in one step, but it could significantly increase the IBIS capabilities in SSO simulations (we believe). In long term, I believe the SSO simulation could be correctly done by IBIS model with the expanding of the IBIS itself. This is the IBIS activity Istvan mentioned in his previous e-mail. As Istvan mentioned, there are other parallel activities with IEEE standard committee and DesignCon on the power integrity. With all the inputs and efforts from the industry experts, we believe that power integrity problem could be correctly modeled and solved in the future. Best regards, Zhiping ----- Original Message ----- From: "Chris Cheng" <Chris.Cheng@xxxxxxxxxxxx> Cc: <si-list@xxxxxxxxxxxxx> Sent: Tuesday, December 28, 2004 9:12 PM Subject: [SI-LIST] Re: Article discussion on bad packages > Istvan, > I thought I understand enough of your company's design methodologies (I > worked on quite a few of them). So I am surprised to hear your response. Can > you honest tell me your company is not running SPICE on "sophisticated IO > circuits" to analyze its performance nor using it to analyze core power > distribution ? Are you relying only on IBIS nowadays ? Or you are preaching > something you don't practice yourself ? > > > -----Original Message----- > From: Istvan NOVAK > To: Chris.Cheng@xxxxxxxxxxxx > Cc: si-list@xxxxxxxxxxxxx > Sent: 12/28/2004 8:36 PM > Subject: Re: [SI-LIST] Re: Article discussion on bad packages > > Chris, > > If you want to simulate PDN SSN, you can do either a > transistor-level SPICE simulation together with the PDN > model, or an approximate behavioral model simulation can > be done. For smaller circuits, transistor level models may > work in SPICE (if you have access to it). For large chunks > of silicon, like CPU cores and sophisticated IO circuits, the > SPICE model may be prohibitively large. Also, for many > users of third-party silicons, transistor-level SPICE model > may not be available. For the above reasons, behavioral > simulations may still be better than doing no simulations at all > > Regards, > > Istvan Novak > SUN Microsystems > > ------------------------------------------------------------------ > 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: > http://www.freelists.org/webpage/si-list > > For help: > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field > > List FAQ wiki page is located at: > http://si-list.org/wiki/wiki.pl?Si-List_FAQ > > List technical documents are available at: > http://www.si-list.org > > List archives are viewable at: > http://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: http://www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org List archives are viewable at: http://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