Hello Cary, Thanks alot for guiding me. I have read those mails. Regards Shiv Mandel, Cary wrote: >Hello Shiv, > >A related question - regarding trimming V/T curve dead-times AND >correlating simulations with Spice - was raised by a colleague of yours >on the IBIS reflector on May 14, 2007. His name was > Akhilesh Chandra - akhilesh.chandra@st.com > >I think the dialog - on the IBIS reflector - with Akhilesh should >contain enough information to answer your question. I suggest you check >the IBIS reflector archives - starting 14 May, which will contain a >record of the dialog with Akilesh. You might want to contact Akilesh >directly. > >Regards, >Cary Mandel > >-----Original Message----- >From: Shiv Harit MATHUR [mailto:shiv.mathur@st.com] >Sent: 30 May 2007 05:39 >To: rrwolff@micron.com; twesterh@sisoft.com; Mandel, Cary >Cc: ibis-users@eda.org >Subject: Re: [IBIS-Users] V/T Window adjustment > >Hello, > >Thanks allot for your prompt and very useful suggestions. > >As you said we can trim off V/T curves dead-times, maintaining corner >correlation intact while losing out synchronisation across corners. >Now if i do so, then how can we validate our model ?? > >Also, does there exist some way to add these trimmed delay values in the >model or the tool for different corners. >I think the dead-time value should be added to the internal delay value >to avoid overclocking. > >Regards >Shiv Harit Mathur > > > >rrwolff@micron.com wrote: > > > >>Shiv, >> >>I have modeled similarly fast switching buffers by removing leading >>"dead" time from the V-t waveforms. I treat min, typ, and max corners >>as independent sets of V-t curves. Make sure to remove the same amount >> >> > > > >>of time from all 4 min curves, typ curves, or max curves to maintain >>the correct timing between the curves to different termination >>voltages. I also document in the Notes section of the model the amount >> >> > > > >>of time I shift the typ relative to the max and the min relative to the >> >> > > > >>max (in case someone wants to match up the spice model to the IBIS >> >> >model). > > >>You only show one set of V-t waveforms in the attached JPEG, but >>assuming that these curves represent the earliest switch times, I would >> >> > > > >>trim off approximately the following delay times from the three >> >> >corners: > > >>Max: 90ps >>Nom: 175ps >>Min: 350ps >> >>I suggest you submit your model to the IBIS Model Review Committee when >> >> > > > >>you are done and ready for a final check. >> >>Regards, >>Randy >> >>Randy Wolff >>SI Modeling Manager >>Signal Integrity R&D Group >>Micron Technology, Inc. >> >> >>-----Original Message----- >>From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On >>Behalf Of Shiv Harit MATHUR >>Sent: Tuesday, May 29, 2007 4:14 AM >>To: ibis-users@eda.org; ibis-users@eda.org >>Cc: Shiv Harit MATHUR >>Subject: [IBIS-Users] V/T Window adjustment >> >>Hello Experts, >> >>I am trying to model a buffer whose freq of operation is 1.5Ghz (time >>period = 666ps). >>While extracting the V/T curve for the buffer we need to take up a >>window of not less than 800ps to cover all the three waveforms. The >>buffer delay in MAX,NOM and MIN CORNERS is 130.31ps, 228.44ps and >>424.08ps respectively. >> >>Please find the snapshot view of the rising output waveform "TXP" of >>the buffer in three corners, "SB" is the Input data given to the buffer >> >> > > > >>(the >> delay values are almost same for the falling stimuli also) >> >>Now the problem is that if I extract and dump these values in the IBIS >>model, the model will certainly fail in the worst and typical cases as >>the bit time is 333ps (< V/T window size). Although it will give a good >> >> > > > >>match only if MAX corner is considered. >> >>Can anybody please suggest, what could be done for this case in order >>to model the behaviour of the buffer correctly in all three corners ? >> >>Regards >>Shiv Harit Mathur >>STMICROELECTRONICS PVT LTD >>INDIA >> >>-- >>This message has been scanned for viruses and dangerous content by >>MailScanner, and is believed to be clean. >> >> >> >> >> >> > > > -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. -------------------------------------------------------------------- |For help or to subscribe/unsubscribe, e-mail majordomo@eda-stds.org |with 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 e-mail a request to ibis-request@eda-stds.org. | |IBIS reflector archives exist under: | | http://www.eda-stds.org/pub/ibis/email_archive/ Recent | http://www.eda-stds.org/pub/ibis/users_archive/ Recent | http://www.eda-stds.org/pub/ibis/email/ E-mail since 1993Received on Wed May 30 04:39:43 2007
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