From owner-ibis Sat May 3 16:03:05 1997 Received: from amdext.amd.com (amdext.amd.com [139.95.251.1]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id QAA08624 for ; Sat, 3 May 1997 16:03:04 -0700 (PDT) From: jerry.isaac@amd.com Received: from amdint.amd.com (amdint.amd.com [139.95.250.1]) by amdext.amd.com (8.8.5/8.8.5/AMD) with ESMTP id QAA06621 for ; Sat, 3 May 1997 16:00:57 -0700 (PDT) Received: from camta4.amd.com (camta4.amd.com [139.95.252.6]) by amdint.amd.com (8.8.5/8.8.5/AMD) with SMTP id QAA28069 for ; Sat, 3 May 1997 16:00:51 -0700 (PDT) Received: by camta4.amd.com (8.6.12+AMD3/AMDSD-1.20+ISO2) id QAA25461; Sat, 3 May 1997 16:00:50 -0700 X400-Received: by mta CAMTA4 in /PRMD=AMD/ADMD=ATTMAIL/C=US; Relayed; 03 May 1997 16:00:49 -0700 X400-Received: by mta CAMTA4-2 in /PRMD=AMD/ADMD=ATTMAIL/C=US; Relayed; 03 May 1997 16:00:49 -0700 Date: 03 May 1997 16:00:49 -0700 Delivery-Date: 03 May 1997 16:00:50 -0700 Message-Type: Multiple Part X400-Originator: Jerry.Isaac@camta4.amd.com X400-MTS-Identifier: [/PRMD=AMD/ADMD=ATTMAIL/C=US;ISOCOR-3355e43c-CAMTA4-2] X400-Recipients: ibis-users@vhdl.org Original-Encoded-Information-Types: IA5-Text X400-Content-Type: P2-1984 Message-ID: <"ISOPRO::DH-EF::7CBC::336BC2F0"*/G=Jerry/S=Isaac/O=camta4/PRMD=AMD/ADMD=ATTMAIL/C=US@MHS> Importance: normal Subject: Questions re: [Rising Waveform], [Falling Waveform] Autoforwarded: FALSE To: ibis-users@vhdl.org Priority: normal Conversion: Allowed Conversion-With-Loss: Allowed Alternate-Recipient: Prohibited Content-Identifier: Questions re: ? Hello, I'm seeking some advice about the subject keywords. I have included them in a model I've developed for a customer (since the drivers I'm modeling do have slew rate control), but I'm not entirely sure how simulators use the V/T tables versus using the [Ramp] data. In particular, I have the following questions: 1) What xxx_fixture values should I specify for my SPICE simulations (and hence place into the IBIS model)? 2) Should the xxx_fixture values vary for each customer based on their application? 3) What would happen (in other words, what would a simulator do?) if the V/T tables use a different loading assumption than the assumptions used to produce the dV/dt_r and dV/dt_f values? (a response that this is not appropriate for an IBIS model would be acceptable to me). 4) Would the simulations be any less accurate if I simply didn't include the V/T tables? Any light shed on this topic (or a reference to an explanation) would be most appreciated. Thank you, Jerry Isaac From owner-ibis Mon May 5 12:01:16 1997 Received: from icx.com (root@fw.icx.com [205.238.6.33]) by server.vhdl.org (8.8.5/8.8.3) with SMTP id MAA18279 for ; Mon, 5 May 1997 12:01:14 -0700 (PDT) Received: by icx.com (/\oo/\ Smail3.1.29.1 #29.2) id ; Mon, 5 May 97 11:59 PDT Received: by icx.com (/\==/\ Smail3.1.28.1 #28.14) id ; Mon, 5 May 97 11:59 PDT Received: by icx.com (/\==/\ Smail3.1.28.1 #28.14) id ; Mon, 5 May 97 11:59 PDT Message-Id: Date: Mon, 5 May 97 11:59 PDT From: bob@icx.com ( Bob Ross) To: ibis-users@vhdl.org, jerry.isaac@amd.com Subject: Re: Questions re: [Rising Waveform], [Falling Waveform] Jerry: I am providing you some thoughts related to how Interconnectix processes the waveform data to add to the responses already provided. I suggest that you actually provide prototypes of your IBIS models to various IBIS CAE vendors found on the IBIS roster document to help validate the performance of your models. Best Regards, Bob Ross Interconnectix Date: 03 May 1997 16:00:49 -0700 > Subject: Questions re: [Rising Waveform], [Falling Waveform] > To: ibis-users@vhdl.org > Hello, I'm seeking some advice about the subject keywords. I have included > them in a model I've developed for a customer (since the drivers I'm modeling > do have slew rate control), but I'm not entirely sure how simulators use > the V/T tables versus using the [Ramp] data. In particular, I have the > following questions: > 1) What xxx_fixture values should I specify for my SPICE simulations (and > hence place into the IBIS model)? For CMOS, we also support typical 50 ohm loads to GND and to Vcc. While permissible, we will get BAD simulations in general if you include a significant (such as 50 pF) C_fixture component. The only cases where the results will be reasonable is if the actual circuit contained that discrete capactance. > 2) Should the xxx_fixture values vary for each customer based on their > application? A major application of IBIS models is for simulation of high-speed signals in transmission line networks that model printed circuit board traces. Such designs typically have transmission line impedances in the 30 to 100 ohm region, and 50 ohms seems like a good nominal value. If you knew beforehand that the characteristic impendance environment was at a different level, then you would get (probably) slighly more accurate by tuning your waveform extractions to the actual characteristic impendance. However, I do not feel this is necessary for a model to be provided for multiple applications. > 3) What would happen (in other words, what would a simulator do?) if the > V/T tables use a different loading assumption than the assumptions used > to produce the dV/dt_r and dV/dt_f values? (a response that this is not > appropriate for an IBIS model would be acceptable to me). In our simulator, the V/T tables always override the [Ramp] data. We use the first two [Rising Waveform] and first two [Falling Waveform] tables encountered. If two tables cause a mathematical inconsistency, (or if the driver is an "Open_***"), then we use just the first table. If there is a mathematical problem (e.g., some really bad data values) then we default to the [Ramp] data, and use its loading assumptions. In all cases, simultors should give a reasonable response for the actual loading conditions that are seen, regardless of whether the time response is V/T or Ramp based. The beginning and ending amplitudes should be based on actual loading conditions in conjunction with the internal model I/V tables. > 4) Would the simulations be any less accurate if I simply didn't include > the V/T tables? Our simulators are more accurate by including the V/T tables to capture some some actual driver pulse shape details that would be seen in practice. To the extent that much of the simulation detail is based on the network topology and its set of distributed loads, a Ramp based driver with correct dt_r and dt_f values also provide accurate simulations. > Any light shed on this topic (or a reference to an explanation) would > be most appreciated. > Thank you, > Jerry Isaac From owner-ibis Wed May 7 14:27:59 1997 Received: from ferrari.sfu.ca (root@ferrari.sfu.ca [142.58.110.11]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id OAA06566; Wed, 7 May 1997 14:27:56 -0700 (PDT) Received: from fraser (fraser [192.168.0.101]) by ferrari.sfu.ca with SMTP (8.8.5/SFU-2.7H) id OAA26257 (from roland@sfu.ca); Wed, 7 May 1997 14:27:11 -0700 (PDT) From: Roland James Chang Received: by fraser (950413.SGI.8.6.12/SFU-2.6C) id OAA27354 (from roland@sfu.ca); Wed, 7 May 1997 14:27:11 -0700 Message-Id: <199705072127.OAA27354@fraser> Subject: help with S2IBIS utility (fwd) To: ibis-users@vhdl.org Date: Wed, 7 May 1997 14:27:10 -0700 (PDT) Cc: ibis-info@vhdl.org X-Mailer: ELM [version 2.4 PL24] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Forwarded message: From owner-ibis@server.vhdl.org Wed May 7 13:48 PDT 1997 From: Roland James Chang Message-Id: <199705071855.LAA20622@fraser> Subject: help with S2IBIS utility To: ibis@vhdl.org Date: Wed, 7 May 1997 11:55:48 -0700 (PDT) X-Mailer: ELM [version 2.4 PL24] MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII Content-Length: 844 Hello, I'm looking for any information on how to use the S2IBIS utility. I have looked through some application notes from CADENCE, as well as some of the syntatctical descriptions of IBIS files versions 1.0 to 2.1. In particular, I'm having trouble with the syntax of the input files that are fed into the S2IBIS utility. Input files are to consist of 3 parts: 1. Header 2. Modified IBIS pin list 3. Spice Input Deck I am having trouble formulating sections 2 and 3. I would be especially interested in any examples that could be provided showing complete input file/output file pairs that were applied to the S2IBIS conversion. Once again, any help would be greatly appreciated, as I have been assigned the task of SPICE to IBIS model conversion for many IC's at work. thanx in advance, roland please send replies to roland@sfu.ca From owner-ibis Thu May 8 06:17:04 1997 Received: from zoom.bga.com (root@zoom.realtime.net [205.238.128.40]) by server.vhdl.org (8.8.5/8.8.3) with SMTP id GAA19729 for ; Thu, 8 May 1997 06:17:04 -0700 (PDT) Received: from russellr.bga.com (apm1-83.realtime.net [205.238.146.83]) by zoom.bga.com (8.6.12/8.6.12) with SMTP id IAA08339 for ; Thu, 8 May 1997 08:16:18 -0500 Message-ID: <3371EE1F.7064@staktek.com> Date: Thu, 08 May 1997 08:15:43 -0700 From: Russell Rapport Reply-To: russellr@staktek.com Organization: Staktek X-Mailer: Mozilla 3.01Gold (Win95; I) MIME-Version: 1.0 To: ibis-users@vhdl.org Subject: subscribe Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Please add me to the mailing list. From owner-ibis Thu May 8 06:30:14 1997 Received: from zoom.bga.com (root@zoom.realtime.net [205.238.128.40]) by server.vhdl.org (8.8.5/8.8.3) with SMTP id GAA19950 for ; Thu, 8 May 1997 06:30:13 -0700 (PDT) Received: from russellr.bga.com (apm1-83.realtime.net [205.238.146.83]) by zoom.bga.com (8.6.12/8.6.12) with SMTP id IAA10199 for ; Thu, 8 May 1997 08:29:29 -0500 Message-ID: <3371F135.AC0@staktek.com> Date: Thu, 08 May 1997 08:28:53 -0700 From: Russell Rapport Reply-To: russellr@staktek.com Organization: Staktek X-Mailer: Mozilla 3.01Gold (Win95; I) MIME-Version: 1.0 To: ibis-users@vhdl.org Subject: s2ibis2 on PC w/Hspice Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit I am having trouble using veribest's s2ibis2.exe on windows NT 4.0 (on Pentium w/32Meg) using Hspice for windows. My problems are 1) I cannot automate the process-I need to give Hspice the file name and rename it to a .out extension each time. 2) There were no working examples supplied, and NCSU ex1-4 cause convergence problems. I would greatly appreciate any working example files, no matter how trivial. I apologize if someone else has posted this concern before: I just joined this mailing list today. From owner-ibis Thu May 8 16:55:04 1997 Received: from amdext.amd.com (amdext.amd.com [139.95.251.1]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id QAA01357 for ; Thu, 8 May 1997 16:55:03 -0700 (PDT) From: jerry.isaac@amd.com Received: from amdint.amd.com (amdint.amd.com [139.95.250.1]) by amdext.amd.com (8.8.5/8.8.5/AMD) with ESMTP id QAA04003 for ; Thu, 8 May 1997 16:53:50 -0700 (PDT) Received: from camta4.amd.com (camta4.amd.com [139.95.252.6]) by amdint.amd.com (8.8.5/8.8.5/AMD) with SMTP id QAA19716 for ; Thu, 8 May 1997 16:53:49 -0700 (PDT) Received: by camta4.amd.com (8.6.12+AMD3/AMDSD-1.20+ISO2) id QAA23607; Thu, 8 May 1997 16:53:47 -0700 X400-Received: by mta CAMTA4 in /PRMD=AMD/ADMD=ATTMAIL/C=US; Relayed; 08 May 1997 16:53:47 -0700 X400-Received: by mta CAMTA4-2 in /PRMD=AMD/ADMD=ATTMAIL/C=US; Relayed; 08 May 1997 16:53:47 -0700 Date: 08 May 1997 16:53:47 -0700 Delivery-Date: 08 May 1997 16:53:47 -0700 Message-Type: Multiple Part X400-Originator: Jerry.Isaac@camta4.amd.com X400-MTS-Identifier: [/PRMD=AMD/ADMD=ATTMAIL/C=US;ISOCOR-33585446-CAMTA4-2] X400-Recipients: ibis-users@vhdl.org Original-Encoded-Information-Types: IA5-Text X400-Content-Type: P2-1984 Message-ID: <"ISOPRO::DH-EF::4FF1::337266D4"*/G=Jerry/S=Isaac/O=camta4/PRMD=AMD/ADMD=ATTMAIL/C=US@MHS> Importance: normal Subject: Thanks Autoforwarded: FALSE To: ibis-users@vhdl.org Priority: normal Conversion: Allowed Conversion-With-Loss: Allowed Alternate-Recipient: Prohibited Content-Identifier: Thanks Thanks to all who responded to my email...Jerry. From owner-ibis Tue May 13 13:17:22 1997 Received: from icx.com (root@fw.icx.com [205.238.6.33]) by server.vhdl.org (8.8.5/8.8.3) with SMTP id NAA02082 for ; Tue, 13 May 1997 13:17:21 -0700 (PDT) Received: by icx.com (/\oo/\ Smail3.1.29.1 #29.2) id ; Tue, 13 May 97 13:16 PDT Received: by icx.com (/\==/\ Smail3.1.28.1 #28.14) id ; Tue, 13 May 97 13:16 PDT Received: by icx.com (/\==/\ Smail3.1.28.1 #28.14) id ; Tue, 13 May 97 13:16 PDT Message-Id: Date: Tue, 13 May 97 13:16 PDT From: bob@icx.com ( Bob Ross) To: ibis-users@vhdl.org Subject: s2ibis2 Version 1.1 Fix Hello: I have posted an interim fix to s2ibis2 version 1.1 to allow the data to be printed with 4 decimal digits instead of 2. This will temporarily get around some of the existing 2-digit resolution problems which can cause some abrupt jumps in the tables. The fix is found on vhdl.org at /pub//ibis/s2ibis/s2ibis2_v1.1/s2ibis2_fix.tar.Z Included is a Sun 4 executable. Bob Ross Inteconnectix From owner-ibis Tue May 13 16:51:39 1997 Received: from ferrari.sfu.ca (root@ferrari.sfu.ca [142.58.110.11]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id QAA05244 for ; Tue, 13 May 1997 16:51:39 -0700 (PDT) Received: from fraser (fraser [192.168.0.101]) by ferrari.sfu.ca with SMTP (8.8.5/SFU-2.7H) id QAA24690 for (from roland@sfu.ca); Tue, 13 May 1997 16:50:51 -0700 (PDT) Received: from localhost by fraser with SMTP (950413.SGI.8.6.12/SFU-2.6C) id QAA21633 for (from roland@sfu.ca); Tue, 13 May 1997 16:50:50 -0700 Date: Tue, 13 May 1997 16:50:49 -0700 (PDT) From: Roland James Chang X-Sender: roland@fraser To: ibis-users@vhdl.org Subject: s2ibis2 error messages Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from QUOTED-PRINTABLE to 8bit by server.vhdl.org id QAA05245 first of all, I would like to extend my thanx to all that replied to my last email seeking help with the s2ibis2 utility. I've now obtained the s2ibis2 utility and have been playing with it for the past few days. I am a university student on a work term at a leading supplier of ATM components, and am finding it quite challenging to learn the entire IBIS modelling standard in the span of a couple of days, so please bear with me, if any of my questions sound too simple (or even stupid) :-) I've been working through the examples (1-4) provided with the s2ibis2 utility but I cannot get example 2 to work (which deals with a simple tristate buffer) It seems to be running into DC convergence problems. This is the output that I get when I run the s2ibis2 utility on example 2 (with tristate.s2i setup for HSPICE): **************************************************************************** * session on an xterm follows **************************************************************************** 17 s2ibis2.sun4 tristate.s2i s2ibis2.sun4 v1.1 -- North Carolina State University s2ibis2.sun4: Reading input file tristate...done. s2ibis2.sun4: Analyzing component MCM Trisate Driver . s2ibis2.sun4: Starting HSpice job with input putout.spi. s2ibis2.sun4: Starting HSpice job with input punout.spi. s2ibis2.sun4: Starting HSpice job with input puxout.spi. s2ibis2.sun4: Starting HSpice job with input dutout.spi. s2ibis2.sun4: Starting HSpice job with input dunout.spi. s2ibis2.sun4: Spice run (MIN) aborted. See file dunout.msg for information. continuing with MAX run. s2ibis2.sun4: Starting HSpice job with input duxout.spi. s2ibis2.sun4: Starting HSpice job with input pdtout.spi. s2ibis2.sun4: Starting HSpice job with input pdnout.spi. s2ibis2.sun4: Starting HSpice job with input pdxout.spi. s2ibis2.sun4: Starting HSpice job with input ddtout.spi. s2ibis2.sun4: Starting HSpice job with input ddnout.spi. s2ibis2.sun4: Starting HSpice job with input ddxout.spi. s2ibis2.sun4: Starting HSpice job with input pctout.spi. s2ibis2.sun4: Spice run (TYP) aborted. See file pctout.msg for information. Curve power clamp not generated. s2ibis2.sun4: Starting HSpice job with input gctout.spi. s2ibis2.sun4: Starting HSpice job with input gcnout.spi. s2ibis2.sun4: Starting HSpice job with input gcxout.spi. s2ibis2.sun4: Starting HSpice job with input rutout.spi. s2ibis2.sun4: Starting HSpice job with input runout.spi. s2ibis2.sun4: Starting HSpice job with input ruxout.spi. s2ibis2.sun4: Starting HSpice job with input rdtout.spi. s2ibis2.sun4: Starting HSpice job with input rdnout.spi. s2ibis2.sun4: Starting HSpice job with input rdxout.spi. s2ibis2.sun4: Starting HSpice job with input a00out.spi. s2ibis2.sun4: Starting HSpice job with input b00out.spi. s2ibis2.sun4: Starting HSpice job with input c00out.spi. s2ibis2.sun4: Starting HSpice job with input x00out.spi. s2ibis2.sun4: Starting HSpice job with input y00out.spi. s2ibis2.sun4: Starting HSpice job with input z00out.spi. s2ibis2.sun4: Error in analysis for pin out. s2ibis2.sun4: Opening file tristate.ibs for writing...done. 18 cat dunout.msg >error ***** hspice job aborted 5.7 real 2.4 user 0.4 sys 19 cat pctout.msg >error ***** hspice job aborted 4.1 real 1.3 user 0.2 sys 20 *********************************************************************** * End Xterm session *********************************************************************** I also found the following inside of dunout.out: *********************************************************************** * excerpt from dunout.out *********************************************************************** . . . **warning** both nodes of source 0:vgnds2i are connected together **warning** negative-mos conductance = 0:mx22 iter= 52 vds,vgs,vbs = -2.74 0.109 0.861 gm,gds,gmbs,ids= 2.147E-03 7.629E-05 -1.532E-04 3.768E-03 convergence problems in dc sweep curves at 3.5000 resimulating with dc convergence controls **diagnostic** dc convergence failure, resetting dcon option to 1 and retrying **diagnostic** dc convergence failure, resetting dcon option to 2 and retrying. **diagnostic** although this circuit has failed to converge to gmindc= 1.000E-12, it did converge to a gmindc= 1.000E-10 for most circuits a value of gmindc 1e-7 or less, is acceptable *** error ***: no convergence in dc sweep curves at 3.5000 ### note2 represents cm**2*um/v**2-sec ### ### @ represents v** ### 2*** diffusion layer process parameters *** rshm= 2.10 ohms/sq cjm= 931.91u f/m**2 cjw= 156.37p f/m ijs= 10.00n amp/m pj= 850.00m volts pjw= 850.00m volts mj0= 487.07m mjw= 478.48m wdf= 0. meters ds= 0. meters 3*** temperature coefficient parameters *** tcv= 0. meters ltcv= 0. meters wtcv= 0. meters bex= -1.50 meters lbex= 0. meters wbex= 0. meters fex= 0. meters lfex= 0. meters wfex= 0. meters trs= 0. meters ltrs= 0. meters wtrs= 0. meters trd= 0. meters ltrd= 0. meters wtrd= 0. meters **warning** both nodes of source 0:vgnds2i wnb= 0. um/v nd0= 0. 1/v lnd= 0. um/v wnd= 0. um/v k2lim= 0. version= 95.20 ### note1 represents cm**2/v**2-sec ### ### note2 represents cm**2*um/v**2-sec ### ### @ represents v** ### 2*** diffusion layer process parameters *** rshm= 2.10 ohms/sq cjm= 931.91u f/m**2 cjw= 156.37p f/m ijs= 10.00n amp/m pj= 850.00m volts pjw= 850.00m volts mj0= 487.07m mjw= 478.48m wdf= 0. meters ds= 0. meters 3*** temperature coefficient parameters *** tcv= 0. meters ltcv= 0. meters wtcv= 0. meters bex= -1.50 meters lbex= 0. meters wbex= 0. meters fex= 0. meters lfex= 0. meters wfex= 0. meters trs= 0. meters ltrs= 0. meters wtrs= 0. meters trd= 0. meters ltrd= 0. meters wtrd= 0. meters **warning** both nodes of source 0:vgnds2i are connected together **warning** negative-mos conductance = 0:mx22 iter= 52 vds,vgs,vbs = -2.74 0.109 0.861 gm,gds,gmbs,ids= 2.147E-03 7.629E-05 -1.532E-04 3.768E-03 convergence problems in dc sweep curves at 3.5000 resimulating with dc convergence controls **diagnostic** dc convergence failure, resetting dcon option to 1 and retrying **diagnostic** dc convergence failure, resetting dcon option to 2 and retrying. **diagnostic** although this circuit has failed to converge to gmindc= 1.000E-12, it did converge to a gmindc= 1.000E-10 for most circuits a value of gmindc 1e-7 or less, is acceptable *** error ***: no convergence in dc sweep curves at 3.5000 ****** * min pullup (output disabled) curve for model tristate_driver ****** dc transfer curves tnom= 25.000 temp= 100.000 ****** . . . ******************************************************************* * end excerpt from dunout.out ******************************************************************* (I'm sorry for the length of this email) I'm wondering if anyone else has had trouble running example 2? If so, was the error the same? and if not does anyone have an explanation for why example 2 doesn't run properly? And finally, has anyone ever received this error message before? "... s2ibis2.sun4: Analyzing component S/UNI PLUS PM5347 . s2ibis2.sun4: Starting HSpice job with input putoutpi.spi. s2ibis2.sun4: Data begin marker transfer not found in output file putoutpi.out. s2ibis2.sun4: Curve pullup not generated. s2ibis2.sun4: Starting HSpice job with input dutoutpi.spi. s2ibis2.sun4: Data begin marker transfer not found in output file dutoutpi.out. s2ibis2.sun4: Curve pullup (output disabled) not generated. ..." Thanx for all your time. sincerely, roland ************************************************************************* *Roland Chang | email: roland@sfu.ca * *Simon Fraser University | OR * *School of Engineering Science | chang@pmc-sierra.bc.ca * *3rd year Computer Engineering Option | * ************************************************************************* From owner-ibis Tue May 13 17:13:11 1997 Received: from lsi.lsil.com (lsi.lsil.com [147.145.40.2]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id RAA05554 for ; Tue, 13 May 1997 17:13:10 -0700 (PDT) Received: from mhost.lsil.com (mhost.lsil.com [147.145.69.84]) by lsi.lsil.com with SMTP id RAA04112 (8.6.12/IDA-1.6 for ); Tue, 13 May 1997 17:03:48 -0700 Received: from useng04 by mhost.lsil.com id AA18939 (4.1/SMI-4.1 for ibis-users@vhdl.org); Tue, 13 May 97 17:02:55 PDT Received: from useng29.useng by useng04 (4.1/SMI-4.1) id AA08739; Tue, 13 May 97 17:02:53 PDT Date: Tue, 13 May 97 17:02:53 PDT From: rkarthik@lsil.com (Karthigeyan Ranganathan) Message-Id: <9705140002.AA08739@useng04> To: ibis-users@vhdl.org Subject: Ibis model for a Differential input receiver Cc: rkarthik@lsil.com Hi I have problems when running ibis on a differential input receiver. I am not quite sure of how to set my .s2i input file correct, especially the usage of [Diff Pin] option in correlation with [Pin] mapping. could someone address my concerns? / mail me a example ibis model with differential inputs. Thanks in advance. Regards, Karthik. From owner-ibis Wed May 14 06:45:28 1997 Received: from crl.dec.com (crl.dec.com [192.58.206.2]) by server.vhdl.org (8.8.5/8.8.3) with SMTP id GAA16885 for ; Wed, 14 May 1997 06:45:27 -0700 (PDT) From: chu@rock.enet.dec.com Received: by crl.dec.com; id AA16488; Wed, 14 May 97 09:10:16 -0400 Received: by easynet.crl.dec.com; id AA11930; Wed, 14 May 97 09:10:15 -0400 Message-Id: <9705141310.AA11930@easynet.crl.dec.com> Received: from rock.enet; by crl.enet; Wed, 14 May 97 09:10:16 EDT Date: Wed, 14 May 97 09:10:16 EDT To: ibis-users@vhdl.org Cc: chu@rock.enet.dec.com Apparently-To: ibis-users@vhdl.org Subject: Re: Ibis model for differential input from rkarthik@lsil.com Karthik: I had a similar problem a few months ago and I asked Alan Glaser for help. For your info, attached below is copy of my original question and his reply. The way I got around it is exactly what he suggested. I had to make a virtual inverter in front of the differential input to provide the out-of-phase signal. Since timing (prop delay) is not utilized in the IBIS model, it makes no difference in the final output. I am not sure if things have changed since. If it has, I certainly would like to know about it. Jeff Chu Digital Equipment Corp. 77 Reed Road Hudson, MA 01749 (508)568-4197 (508)568-5195 fax ===================================================================================== ===================================================================================== Hi I have problems when running ibis on a differential input receiver. I am not quite sure of how to set my .s2i input file correct, especially the usage of [Diff Pin] option in correlation with [Pin] mapping. could someone address my concerns? / mail me a example ibis model with differential inputs. Thanks in advance. Regards, Karthik. % ====== Internet headers and postmarks ====== % Received: from mail13.digital.com by us7rmc.bb.dec.com (5.65/rmc-17Jan97) id AA20499; Tue, 13 May 97 20:45:18 -0400 % Received: from server.vhdl.org by mail13.digital.com (8.7.5/UNX 1.5/1.0/WV) id UAA11511; Tue, 13 May 1997 20:38:38 -0400 (EDT) % Received: from lsi.lsil.com (lsi.lsil.com [147.145.40.2]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id RAA05554 for ; Tue, 13 May 1997 17:13:10 -0700 (PDT) % Received: from mhost.lsil.com (mhost.lsil.com [147.145.69.84]) by lsi.lsil.com with SMTP id RAA04112 (8.6.12/IDA-1.6 for ); Tue, 13 May 1997 17:03:48 -0700 % Received: from useng04 by mhost.lsil.com id AA18939 (4.1/SMI-4.1 for ibis-users@vhdl.org); Tue, 13 May 97 17:02:55 PDT % Received: from useng29.useng by useng04 (4.1/SMI-4.1) id AA08739; Tue, 13 May 97 17:02:53 PDT % Date: Tue, 13 May 97 17:02:53 PDT % From: rkarthik@lsil.com (Karthigeyan Ranganathan) % Message-Id: <9705140002.AA08739@useng04> % To: ibis-users@vhdl.org % Subject: Ibis model for a Differential input receiver % Cc: rkarthik@lsil.com ==================================================================================== ==================================================================================== From: CRL::"awglaser@eos.ncsu.edu" 25-FEB-1997 11:48:57.33 To: rock::chu CC: awglaser@eos.ncsu.edu (Alan Wolfram Glaser) Subj: Re: your mail > Alan: Please help me with the following on your spice to ibis conversion program. > How do you specify differential inputs together with an enable pin in the pin list? The > six valid input pin formats do not include the option of differential inputs. In this > particular circuit I have, I need to control the two differential inputs to make the output > swing. How do I do it? > > Thank you very much for your help > Jeff Chu > Digital Equipment Corp. > 77 Reed Rpad > Hudson, MA > 01749 > (508)568-4197 > (508)568-5195 fax Jeff: Unfortunately, s2ibis2 doesn't have an automatic way to control two inputs. The only thing I can suggest it to let s2ibis2 create the input files, edit them by hand to insert the source for the second input, delete the output files (*.out) then re-run s2ibis2. (It will use the SPICE files that already exist.) Hope this helps. Regards, -- Alan Glaser "It's not a competition, ECE Dept. it's just a mint..." - K North Carolina State University % ====== Internet headers and postmarks (see DECWRL::GATEWAY.DOC) ====== % Received: by easynet.crl.dec.com; id AA25311; Tue, 25 Feb 97 11:48:56 -0500 % Received: by crl.dec.com; id AA24632; Tue, 25 Feb 97 11:47:56 -0500 % Received: (from awglaser@localhost) by c11167-343dan.ece.ncsu.edu (8.8.4/EC02Jan97) id LAA27298; Tue, 25 Feb 1997 11:42:14 -0500 (EST) % From: awglaser@eos.ncsu.edu % Message-Id: <199702251642.LAA27298@c11167-343dan.ece.ncsu.edu> % Subject: Re: your mail % To: rock::chu % Date: Tue, 25 Feb 1997 11:42:13 -0500 (EST) % Cc: awglaser@eos.ncsu.edu (Alan Wolfram Glaser) % In-Reply-To: <9702192149.AA29529@easynet.crl.dec.com> from "chu@rock.enet.dec.com" at Feb 19, 97 04:49:53 pm % X-Mailer: ELM [version 2.4 PL24/POP] % Mime-Version: 1.0 % Content-Type: text/plain; charset=US-ASCII % Content-Transfer-Encoding: 7bit From owner-ibis Wed May 14 08:57:27 1997 Received: from natsemi-bh.nsc.com (natsemi-bh.nsc.com [204.163.202.66]) by server.vhdl.org (8.8.5/8.8.3) with SMTP id IAA19131 for ; Wed, 14 May 1997 08:57:26 -0700 (PDT) Received: (from uucp@localhost) by natsemi-bh.nsc.com (8.6.12/8.6.11) id IAA01003; Wed, 14 May 1997 08:56:04 -0700 Received: from nsc.nsc.com by natsemi-bh.nsc.com via smap (3.2) id xma026676; Wed, 14 May 97 08:51:21 -0700 Received: from lightning.nsc.com by nsc.nsc.com (5.65/1.34) with SMTP id AA13581 for ibis-users@vhdl.org; Wed, 14 May 97 08:51:44 -0700 Received: from kural by rockie.nsc.com (4.1/SMI-4.1) id AA23849; Wed, 14 May 97 08:55:24 PDT Date: Wed, 14 May 97 08:55:24 PDT From: huq@rockie.nsc.com (Syed Huq) Message-Id: <9705141555.AA23849@rockie.nsc.com> To: ibis-users@vhdl.org, roland@sfu.ca Subject: Re: s2ibis2 error messages Cc: huq@rockie.nsc.com Content-Type: X-sun-attachment ---------- X-Sun-Data-Type: text X-Sun-Data-Description: text X-Sun-Data-Name: text X-Sun-Content-Lines: 263 Roland, I am attaching a mail msg from the reflector where this was detected and solved earlier. It has to do with naming the gnd node and decreasing the sweep ranges.(Pls refer to mail). I also saw the 'Data Begin marker' msg before and I think it related to wrong syntax in the .s2i file. Regards, Syed. > From owner-ibis@server.vhdl.org Tue May 13 18:09:36 1997 > Date: Tue, 13 May 1997 16:50:49 -0700 (PDT) > From: Roland James Chang > X-Sender: roland@fraser > To: ibis-users@vhdl.org > Subject: s2ibis2 error messages > Content-Type> : > TEXT/PLAIN> ; > charset=US-ASCII> > Content-Transfer-Encoding: QUOTED-PRINTABLE > > first of all, I would like to extend my thanx to all that replied to my > last email seeking help with the s2ibis2 utility. I've now obtained the > s2ibis2 utility and have been playing with it for the past few days. =20 > > I am a university student on a work term at a leading supplier of ATM > components, and am finding it quite challenging to learn the entire IBIS > modelling standard in the span of a couple of days, so please bear with > me, if any of my questions sound too simple (or even stupid) :-) > > I've been working through the examples (1-4) provided with the s2ibis2 > utility but I cannot get example 2 to work (which deals with a simple > tristate buffer) It seems to be running into DC convergence problems. > This is the output that I get when I run the s2ibis2 utility on example 2 > (with tristate.s2i setup for HSPICE): > > ***************************************************************************= > * > * session on an xterm follows > ***************************************************************************= > * > 17 s2ibis2.sun4 tristate.s2i > > s2ibis2.sun4 v1.1 -- North Carolina State University > s2ibis2.sun4: Reading input file tristate...done. > s2ibis2.sun4: Analyzing component MCM Trisate Driver . > s2ibis2.sun4: Starting HSpice job with input putout.spi. > s2ibis2.sun4: Starting HSpice job with input punout.spi. > s2ibis2.sun4: Starting HSpice job with input puxout.spi. > s2ibis2.sun4: Starting HSpice job with input dutout.spi. > s2ibis2.sun4: Starting HSpice job with input dunout.spi. > s2ibis2.sun4: Spice run (MIN) aborted. See file dunout.msg for > information. > continuing with MAX run. > s2ibis2.sun4: Starting HSpice job with input duxout.spi. > s2ibis2.sun4: Starting HSpice job with input pdtout.spi. > s2ibis2.sun4: Starting HSpice job with input pdnout.spi. > s2ibis2.sun4: Starting HSpice job with input pdxout.spi. > s2ibis2.sun4: Starting HSpice job with input ddtout.spi. > s2ibis2.sun4: Starting HSpice job with input ddnout.spi. > s2ibis2.sun4: Starting HSpice job with input ddxout.spi. > s2ibis2.sun4: Starting HSpice job with input pctout.spi. > s2ibis2.sun4: Spice run (TYP) aborted. See file pctout.msg for > information. > Curve power clamp not generated. > s2ibis2.sun4: Starting HSpice job with input gctout.spi. > s2ibis2.sun4: Starting HSpice job with input gcnout.spi. > s2ibis2.sun4: Starting HSpice job with input gcxout.spi. > s2ibis2.sun4: Starting HSpice job with input rutout.spi. > s2ibis2.sun4: Starting HSpice job with input runout.spi. > s2ibis2.sun4: Starting HSpice job with input ruxout.spi. > s2ibis2.sun4: Starting HSpice job with input rdtout.spi. > s2ibis2.sun4: Starting HSpice job with input rdnout.spi. > s2ibis2.sun4: Starting HSpice job with input rdxout.spi. > s2ibis2.sun4: Starting HSpice job with input a00out.spi. > s2ibis2.sun4: Starting HSpice job with input b00out.spi. > s2ibis2.sun4: Starting HSpice job with input c00out.spi. > s2ibis2.sun4: Starting HSpice job with input x00out.spi. > s2ibis2.sun4: Starting HSpice job with input y00out.spi. > s2ibis2.sun4: Starting HSpice job with input z00out.spi. > s2ibis2.sun4: Error in analysis for pin out. > s2ibis2.sun4: Opening file tristate.ibs for writing...done. > 18 cat dunout.msg > >error ***** hspice job aborted > 5.7 real 2.4 user 0.4 sys > 19 cat pctout.msg > >error ***** hspice job aborted > 4.1 real 1.3 user 0.2 sys > 20 > > *********************************************************************** > * End Xterm session > *********************************************************************** > > I also found the following inside of dunout.out: > > > *********************************************************************** > * excerpt from dunout.out > *********************************************************************** > =2E > =2E > =2E > **warning** both nodes of source 0:vgnds2i > are connected together > > **warning** negative-mos conductance =3D 0:mx22 iter=3D 5= > 2 > vds,vgs,vbs =3D -2.74 0.109 0.861 > gm,gds,gmbs,ids=3D 2.147E-03 7.629E-05 -1.532E-04 3.768E-03 > convergence problems in dc sweep curves at 3.5000 > resimulating with dc convergence controls > > > **diagnostic** dc convergence failure, > resetting dcon option to 1 and retrying > > > **diagnostic** dc convergence failure, > resetting dcon option to 2 and retrying. > > > **diagnostic** although this circuit has failed to converge > to gmindc=3D 1.000E-12, it did converge to a gmindc=3D 1.000E-10 > for most circuits a value of gmindc 1e-7 or less, is acceptable > > > > > *** error ***: no convergence in dc sweep curves at 3.5000 > > ### note2 represents cm**2*um/v**2-sec ### > > ### @ represents v** ### > > 2*** diffusion layer process parameters *** > rshm=3D 2.10 ohms/sq cjm=3D 931.91u f/m**2 cjw=3D 156.37p= > f/m > ijs=3D 10.00n amp/m pj=3D 850.00m volts pjw=3D 850.00m > volts > mj0=3D 487.07m mjw=3D 478.48m wdf=3D 0. > meters > ds=3D 0. meters > > 3*** temperature coefficient parameters *** > tcv=3D 0. meters ltcv=3D 0. meters wtcv=3D 0. > meters > bex=3D -1.50 meters lbex=3D 0. meters wbex=3D 0. > meters > fex=3D 0. meters lfex=3D 0. meters wfex=3D 0. > meters > trs=3D 0. meters ltrs=3D 0. meters wtrs=3D 0. > meters > trd=3D 0. meters ltrd=3D 0. meters wtrd=3D 0. > meters > > **warning** both nodes of source 0:vgnds2i > wnb=3D 0. um/v nd0=3D 0. 1/v lnd=3D 0. = > um/v > wnd=3D 0. um/v k2lim=3D 0. version=3D 95.20 > > ### note1 represents cm**2/v**2-sec ### > > ### note2 represents cm**2*um/v**2-sec ### > > ### @ represents v** ### > > 2*** diffusion layer process parameters *** > rshm=3D 2.10 ohms/sq cjm=3D 931.91u f/m**2 cjw=3D 156.37p= > f/m > ijs=3D 10.00n amp/m pj=3D 850.00m volts pjw=3D 850.00m > volts > mj0=3D 487.07m mjw=3D 478.48m wdf=3D 0. > meters > ds=3D 0. meters > > 3*** temperature coefficient parameters *** > tcv=3D 0. meters ltcv=3D 0. meters wtcv=3D 0. > meters > bex=3D -1.50 meters lbex=3D 0. meters wbex=3D 0. > meters > fex=3D 0. meters lfex=3D 0. meters wfex=3D 0. > meters > trs=3D 0. meters ltrs=3D 0. meters wtrs=3D 0. > meters > trd=3D 0. meters ltrd=3D 0. meters wtrd=3D 0. > meters > > **warning** both nodes of source 0:vgnds2i > are connected together > > **warning** negative-mos conductance =3D 0:mx22 iter=3D 5= > 2 > vds,vgs,vbs =3D -2.74 0.109 0.861 > gm,gds,gmbs,ids=3D 2.147E-03 7.629E-05 -1.532E-04 3.768E-03 > convergence problems in dc sweep curves at 3.5000 > resimulating with dc convergence controls > > > **diagnostic** dc convergence failure, > resetting dcon option to 1 and retrying > > > **diagnostic** dc convergence failure, > resetting dcon option to 2 and retrying. > > > **diagnostic** although this circuit has failed to converge > to gmindc=3D 1.000E-12, it did converge to a gmindc=3D 1.000E-10 > for most circuits a value of gmindc 1e-7 or less, is acceptable > > > > > *** error ***: no convergence in dc sweep curves at 3.5000 > > > > ****** > * min pullup (output disabled) curve for model tristate_driver > ****** dc transfer curves tnom=3D 25.000 temp=3D 100.000 > ****** > > =2E > =2E > =2E > > ******************************************************************* > * end excerpt from dunout.out > ******************************************************************* > > (I'm sorry for the length of this email) > > I'm wondering if anyone else has had trouble running example 2? > If so, was the error the same? and if not does anyone have an explanation > for why example 2 doesn't run properly? > > And finally, has anyone ever received this error message before? > > "... > s2ibis2.sun4: Analyzing component S/UNI PLUS PM5347 . > s2ibis2.sun4: Starting HSpice job with input putoutpi.spi. > s2ibis2.sun4: Data begin marker transfer not found in output file > putoutpi.out. > s2ibis2.sun4: Curve pullup not generated. > s2ibis2.sun4: Starting HSpice job with input dutoutpi.spi. > s2ibis2.sun4: Data begin marker transfer not found in output file > dutoutpi.out. > s2ibis2.sun4: Curve pullup (output disabled) not generated. > =2E.." > > Thanx for all your time. > sincerely, > > roland > ************************************************************************* > *Roland Chang | email: roland@sfu.ca * > *Simon Fraser University | OR * > *School of Engineering Science | chang@pmc-sierra.bc.ca * > *3rd year Computer Engineering Option | * > ************************************************************************* > > ---------- X-Sun-Data-Type: mail-file X-Sun-Data-Name: mail-file X-Sun-Encoding-Info: uuencode X-Sun-Content-Lines: 66 begin 600 mail-file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nd finally, has anyone ever received this error message before? > > "... > s2ibis2.sun4: Analyzing component S/UNI PLUS PM5347 . > s2ibis2.sun4: Starting HSpice job with input putoutpi.spi. > s2ibis2.sun4: Data begin marker transfer not found in output file > putoutpi.out. > s2ibis2.sun4: Curve pullup not generated. > s2ibis2.sun4: Starting HSpice job with input dutoutpi.spi. > s2ibis2.sun4: Data begin marker transfer not found in output file > dutoutpi.out. > s2ibis2.sun4: Curve pullup (output disabled) not generated. > =2E.." Roland: S2ibis2 looks for certain "marker" words or symbols that denote the start of the data in the output file. In this case, since you're using HSPICE, s2ibis2 looks for the word "transfer" in the output file, and marks where it finds it as the start of data. (It's not actually the exact beginning of the data, but it allows s2ibis2 to skip over the huge "prelude" portion of the output file.) Basically, the error message just means that s2ibis2 couldn't find the marker it was looking for. You can find all of the markers it uses in the file s2istrng.h. The variable names are VIDataBeginMarker, tranDataBeginMarker, and dataEndMarker. Each variable has five possible values, corresponding to the various flavors of SPICE simulator (HSPICE, PSpice, SPICE2, Spice3 and Spectre, in that order). Hope this helps. Regards, -- Alan Glaser "It's not a competition, ECE Dept. it's just a mint..." - K North Carolina State University From owner-ibis Thu May 15 11:10:52 1997 Received: from relayhost.vlsi.com (tweety.vlsi.com [134.27.20.23]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id LAA14383 for ; Thu, 15 May 1997 11:10:52 -0700 (PDT) From: harish.patel@tempe.vlsi.com Received: from relayhost.tempe.vlsi.com (anubis.tempe.vlsi.com [134.27.128.1]) by relayhost.vlsi.com (8.6.12/Hub-Perlotto/050895) with ESMTP id MAA04796 for ; Thu, 15 May 1997 12:20:24 -0700 Received: from pcdmail.tempe.vlsi.com (hole.tempe.vlsi.com [134.27.128.11]) by relayhost.tempe.vlsi.com (8.6.9/Hub-Perlotto/101195) with ESMTP id LAA11907 for ; Thu, 15 May 1997 11:09:35 -0700 Received: from mardi (mardi [134.27.133.22]) by pcdmail.tempe.vlsi.com (8.6.9/Hub-Perlotto/032095) with SMTP id LAA25159 for ; Thu, 15 May 1997 11:09:34 -0700 Received: by mardi id AA17817; Thu, 15 May 1997 11:09:33 -0700 Date: Thu, 15 May 1997 11:09:33 -0700 Message-Id: <9705151809.AA17817@mardi> To: ibis-users@vhdl.org Subject: Problem regarding running s2ibis2 program Mime-Version: 1.0 Content-Type: multipart/mixed;boundary=5ad_11f7-5662_7113-3429_28eb --5ad_11f7-5662_7113-3429_28eb Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-MD5: 3LnrSh9LGFsZtcqD3DoPpw== X-Sun-Data-Type: text Hello, NEED HELP... I am trying to use s2ibis2 program and I am having problem executing it. I created a file test.s2i and pad.sp and tried to run it and I am getting following error: s2ibis2.solaris v1.1 -- North Carolina State University s2ibis2.solaris: Reading input file test...done. s2ibis2.solaris: Analyzing component PHXIO . s2ibis2.solaris: Unable to open file pad.sp for reading. s2ibis2.solaris: No such file or directory s2ibis2.solaris: Couldn't set up Spice file for pullup curve. s2ibis2.solaris: Unable to open file pad.sp for reading. s2ibis2.solaris: No such file or directory s2ibis2.solaris: Couldn't set up Spice file for pullup (output disabled) curve. s2ibis2.solaris: Unable to open file pad.sp for reading. s2ibis2.solaris: No such file or directory s2ibis2.solaris: Couldn't set up Spice file for pulldown curve. s2ibis2.solaris: Unable to open file pad.sp for reading. s2ibis2.solaris: No such file or directory s2ibis2.solaris: Couldn't set up Spice file for pulldown (output disabled) curve. s2ibis2.solaris: Unable to open file pad.sp for reading. s2ibis2.solaris: No such file or directory s2ibis2.solaris: Couldn't set up Spice file for power clamp curve. s2ibis2.solaris: Unable to open file pad.sp for reading. s2ibis2.solaris: No such file or directory s2ibis2.solaris: Couldn't set up Spice file for ground clamp curve. s2ibis2.solaris: Unable to open file pad.sp for reading. s2ibis2.solaris: No such file or directory s2ibis2.solaris: Unable to open file pad.sp for reading. s2ibis2.solaris: No such file or directory s2ibis2.solaris: Error in analysis for pin out. s2ibis2.solaris: Unable to open file pad.sp for reading. s2ibis2.solaris: No such file or directory s2ibis2.solaris: Couldn't set up Spice file for power clamp curve. s2ibis2.solaris: Unable to open file pad.sp for reading. s2ibis2.solaris: No such file or directory s2ibis2.solaris: Couldn't set up Spice file for ground clamp curve. s2ibis2.solaris: Error in analysis for pin in. s2ibis2.solaris: Unable to open file pad.sp for reading. s2ibis2.solaris: No such file or directory s2ibis2.solaris: Couldn't set up Spice file for power clamp curve. s2ibis2.solaris: Unable to open file pad.sp for reading. s2ibis2.solaris: No such file or directory s2ibis2.solaris: Couldn't set up Spice file for ground clamp curve. s2ibis2.solaris: Error in analysis for pin oen. s2ibis2.solaris: Opening file test.ibs for writing...done. First of all it's not able to read file pad.sp from my working dir. Can someone suggest something?? Thanks in advance. --5ad_11f7-5662_7113-3429_28eb Content-Type: application/octet-stream; name=test.s2i Content-Transfer-Encoding: 7bit Content-MD5: h8uE/ukx5zdeZN6RRt2HwQ== Content-Description: test.s2i Content-Disposition: attachment; filename=test.s2i | | s2ibis2 command file | [IBIS Ver] 2.1 [File rev] 0 [Spice type] hspice [Component] PHXIO [Spice file] pad.sp [Voltage range] 3.3 3.0 3.6 [Pin] vdd vdd VCC POWER gnd gnd GND GND out out out ptx5c50z 200.0m 5.0nh 1.5pf -> in oen in in in Input1 oen oen oen Enable1 [Model] ptx5c50z [Model type] 3-state [Enable] Active-Low [Model File] model.typ model.min model.max [Vinl] 0.8 [Vinh] 2.0 [Model] Input1 [Model type] Input [Model File] model.typ model.min model.max [Vinl] 0.8 [Vinh] 2.0 [Model] Enable1 [Model type] Input [Polarity] Inverting [Model File] model.typ model.min model.max [Vinl] 0.8 [Vinh] 2.0 --5ad_11f7-5662_7113-3429_28eb Content-Type: application/octet-stream; name=pad.sp Content-Transfer-Encoding: 7bit Content-MD5: 0WGSXty9NbG67lSu3JoPYg== Content-Description: pad.sp Content-Disposition: attachment; filename=pad.sp ***** s2ibis SPICE INPUT DECK ***** .options LVLTIM=3 DVDT=2 ACCURATE gmindc = 1.0e-7 .inc "/home/hpatel/ibis/pad5_model/vsc7p38/vcmn5_rev2p1_diodes.inc" .inc "/clibs/process/vlsi/cmn5/vcmn5_rev2p1.lib" .include `/home/hpatel/bin/transistors.sub` X11 vdd gnd in out11 oen ptx5c50z .include `spi/ptx5c50z.spi` ***.END --5ad_11f7-5662_7113-3429_28eb-- ___________________________________________________________________ Harish Patel VLSI Technology, Inc. harish.patel@tempe.vlsi.com Computing Products Group 602-752-6202/Fax:602-752-6002 Tempe, Arizona ___________________________________________________________________ A policy is a temporary creed liable to be changed, but while it holds good it has to be pursued with apostolic zeal. -- Mahatma Gandhi From owner-ibis Fri May 16 16:04:58 1997 Received: from ferrari.sfu.ca (root@ferrari.sfu.ca [142.58.110.11]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id QAA11134 for ; Fri, 16 May 1997 16:04:57 -0700 (PDT) Received: from fraser (fraser [192.168.0.101]) by ferrari.sfu.ca with SMTP (8.8.5/SFU-2.7H) id QAA09528 for (from roland@sfu.ca); Fri, 16 May 1997 16:04:03 -0700 (PDT) Received: from localhost by fraser with SMTP (950413.SGI.8.6.12/SFU-2.6C) id QAA03828 for (from roland@sfu.ca); Fri, 16 May 1997 16:04:02 -0700 Date: Fri, 16 May 1997 16:04:02 -0700 (PDT) From: Roland James Chang X-Sender: roland@fraser To: ibis-users@vhdl.org Subject: HSPICE incorrect V-I tables? Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from QUOTED-PRINTABLE to 8bit by server.vhdl.org id QAA11135 Hello, I am having trouble trying to get output I obtained using HSPICE to match the example files provided with the s2ibis2 utility (generated with spectre supposedly) there are four examples, and likewise four example .ibs files provided with the s2ibis2 utility, my_buf.ibs my_tri.ibs my_chip.ibs my_mpow.ibs Take for example my_chip.ibs, When I generated the chip.ibs file for it, the tables for the model --input-- matched the example my_chip.ibs file fine as shown below in shortened form: (POWER_clamp matched as well) ******** my_chip.ibs file (included with s2ibis2 utility) ******* . . . |************************************************************************ | Model input |************************************************************************ | [Model] input Model_type Input C_comp 5.00pF 5.00pF 5.00pF | | [Temperature Range] 27.00 100.00 0.000 [Voltage Range] 3.30V 3.00V 3.60V [GND_clamp] | voltage I(typ) I(min) I(max) | -3.30 -30.81mA -32.43mA -30.24mA -3.20 -29.63mA -31.24mA -29.05mA -3.10 -28.44mA -30.06mA -27.86mA -3.00 -27.25mA -28.87mA -26.67mA -2.90 -26.07mA -27.69mA -25.48mA ******** chip.ibs which I generated using HSPICE ******* . . . |************************************************************************ | Model input |************************************************************************ | [Model] input Model_type Input C_comp 5.00pF 5.00pF 5.00pF | | [Temperature Range] 27.00 100.00 0.000 [Voltage Range] 3.30V 3.00V 3.60V [GND_clamp] | voltage I(typ) I(min) I(max) | -3.30 -30.91mA -32.27mA -30.42mA -3.20 -29.72mA -31.09mA -29.23mA -3.10 -28.53mA -29.90mA -28.04mA -3.00 -27.35mA -28.72mA -26.85mA -2.90 -26.16mA -27.53mA -25.67mA -2.80 -24.98mA -26.35mA -24.48mA However, when I looked at the V_I tables generated for the model --driver-- and --tristate driver-- I found that my HSPICE files had ridiculously huge values: ******** my_chip.ibs file (included with s2ibis2 utility) ******* . . . |************************************************************************ | Model driver |************************************************************************ | [Model] driver Model_type Output Polarity Non-Inverting C_comp 5.00pF 5.00pF 5.00pF | | [Temperature Range] 27.00 100.00 0.000 [Voltage Range] 3.30V 3.00V 3.60V [Pulldown] | voltage I(typ) I(min) I(max) | -3.30 -1.94A -1.61A -2.12A -3.10 -1.78A -1.48A -1.94A -2.90 -1.62A -1.35A -1.76A -2.70 -1.46A -1.22A -1.59A -2.50 -1.30A -1.10A -1.41A -2.30 -1.14A -0.97A -1.23A -2.10 -0.98A -0.84A -1.06A . . . | |************************************************************************ | Model tristate_driver |************************************************************************ | [Model] tristate_driver Model_type 3-state Polarity Non-Inverting Enable Active-Low C_comp 5.00pF 5.00pF 5.00pF | [GND_clamp] | voltage I(typ) I(min) I(max) | -3.30 -1.88A -1.57A -2.04A -3.20 -1.80A -1.51A -1.96A -3.10 -1.72A -1.44A -1.87A -3.00 -1.64A -1.38A -1.78A -2.90 -1.56A -1.31A -1.69A -2.80 -1.48A -1.25A -1.60A -2.70 -1.40A -1.19A -1.52A -2.60 -1.32A -1.12A -1.43A -2.50 -1.24A -1.06A -1.34A . . . ******** chip.ibs which I generated using HSPICE ******* . . . |************************************************************************ | Model driver |************************************************************************ | [Model] driver Model_type Output Polarity Non-Inverting C_comp 5.00pF 5.00pF 5.00pF | | [Temperature Range] 27.00 100.00 0.000 [Voltage Range] 3.30V 3.00V 3.60V [Pulldown] | voltage I(typ) I(min) I(max) | -3.30 -3.777e+21A -1.000e+25A -3.957e+19A -3.10 -3.777e+21A -1.000e+25A -3.957e+19A -2.90 -3.777e+21A -1.000e+25A -3.957e+19A -2.70 -3.777e+21A -1.000e+25A -3.957e+19A -2.50 -3.777e+21A -3.526e+24A -3.957e+19A -2.30 -3.777e+21A -7.015e+21A -3.957e+19A -2.10 -3.777e+21A -1.395e+19A -3.957e+19A . . . |************************************************************************ | Model tristate_driver |************************************************************************ | [Model] tristate_driver Model_type 3-state Polarity Non-Inverting Enable Active-Low C_comp 5.00pF 5.00pF 5.00pF | [GND_clamp] | voltage I(typ) I(min) I(max) | -3.30 -3.777e+21A -1.000e+25A -3.957e+19A -3.20 -3.777e+21A -1.000e+25A -3.957e+19A -3.10 -3.777e+21A -1.000e+25A -3.957e+19A -3.00 -3.777e+21A -1.000e+25A -3.957e+19A -2.90 -3.777e+21A -1.000e+25A -3.957e+19A -2.80 -3.777e+21A -1.000e+25A -3.957e+19A -2.70 -3.777e+21A -1.000e+25A -3.957e+19A -2.60 -3.777e+21A -1.000e+25A -3.957e+19A -2.50 -3.777e+21A -3.526e+24A -3.957e+19A -2.40 -3.777e+21A -1.573e+23A -3.957e+19A . . . I think someone mentioned this in their replies to my previous posts, but it was a short reply. Anyone experience this problem?(and why does it happen?) And if so, how did you correct it? Once again, many thanx! (and sorry for all the traffic!) roland ************************************************************************* *Roland Chang | email: roland@sfu.ca * *Simon Fraser University | OR * *School of Engineering Science | chang@pmc-sierra.bc.ca * *3rd year Computer Engineering Option | * ************************************************************************* From owner-ibis Mon May 19 07:23:14 1997 Received: from tcemail.indy.tce.com (inet-gw.indy.tce.com [157.254.232.6]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id HAA04883 for ; Mon, 19 May 1997 07:23:14 -0700 (PDT) Received: (from uucp@localhost) by tcemail.indy.tce.com (8.8.4/8.8.3) id JAA27799 for ; Mon, 19 May 1997 09:21:51 -0500 (EST) Received: from cts2.indy.tce.com(157.254.98.70) by seawall.indy.tce.com via smap (V1.3) id sma027791; Mon May 19 09:21:21 1997 Received: by MSMAIL.INDY.TCE.COM with Microsoft Mail id <33807019@MSMAIL.INDY.TCE.COM>; Mon, 19 May 97 09:22:01 CST From: Girma Nebiyou To: "'ibis-users@vhdl.org'" Subject: s2ibis2 for NT Date: Mon, 19 May 97 09:21:00 CST Message-ID: <33807019@MSMAIL.INDY.TCE.COM> Encoding: 7 TEXT X-Mailer: Microsoft Mail V3.0 Hello, Are there any working examples of IBIS models generated using s2ibis2 (NT ). I would appereciate it if anyone who has used the program contacts me. Nebiyou Girma From owner-ibis Tue May 20 13:02:58 1997 Received: from ferrari.sfu.ca (root@ferrari.sfu.ca [142.58.110.11]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id NAA02259 for ; Tue, 20 May 1997 13:02:57 -0700 (PDT) Received: from fraser (fraser [192.168.0.101]) by ferrari.sfu.ca with SMTP (8.8.5/SFU-2.7H) id NAA07350 for (from roland@sfu.ca); Tue, 20 May 1997 13:02:02 -0700 (PDT) Received: from localhost by fraser with SMTP (950413.SGI.8.6.12/SFU-2.6C) id NAA18630 for (from roland@sfu.ca); Tue, 20 May 1997 13:02:00 -0700 Date: Tue, 20 May 1997 13:02:00 -0700 (PDT) From: Roland James Chang X-Sender: roland@fraser To: ibis-users@vhdl.org Subject: SPICE Convergence Tricks - Consequences? Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Once again, a big thanks to all who replied to my last question. :-) I've been using several tricks to try to solve SPICE convergence problems: -adding a 0.001ohm resistor in seris with the stimulating source -increasing the value of the ITL1 to 300-500. (more iterations allowed) -relaxing ABSTOL -decreasing the sweep of the stimulus (I couldn't quite get this one to work) Many people mentioned that convergence problems are quite common, I would like to know how common are they? Furthermore, I am curious if anyone has a convergence fix that works everytime, as it seems tedious to try to get things to converge everytime just by trial and error fixes. Also, what kinds of side-effects, or problems (in terms of IBIS modelling) have people encountered by forcing the analysis to converge via fancy SPICE tricks? One last question regards clarification about typ, min, and max curves. When one is generating curves for the typical case, suppose the typical case passes but both the min and max fail, the columns should read NA for min and max right? Now should I go back and try to tweak the min and max to converge? OR are some curves meant to only work for the typical case? Many thanks in advance, Regards, roland ************************************************************************* *Roland Chang | email: roland@sfu.ca * *Simon Fraser University | OR * *School of Engineering Science | chang@pmc-sierra.bc.ca * *3rd year Computer Engineering Option | * ************************************************************************* From owner-ibis Tue May 20 17:56:41 1997 Received: from icx.com (root@fw.icx.com [205.238.6.33]) by server.vhdl.org (8.8.5/8.8.3) with SMTP id RAA07581 for ; Tue, 20 May 1997 17:56:40 -0700 (PDT) Received: by icx.com (/\oo/\ Smail3.1.29.1 #29.2) id ; Tue, 20 May 97 17:55 PDT Received: by icx.com (/\==/\ Smail3.1.28.1 #28.14) id ; Tue, 20 May 97 17:55 PDT Received: by icx.com (/\==/\ Smail3.1.28.1 #28.14) id ; Tue, 20 May 97 17:55 PDT Message-Id: Date: Tue, 20 May 97 17:55 PDT From: bob@icx.com ( Bob Ross) To: ibis-users@vhdl.org Subject: UPDATED ibischk2+ EXECUTABLES To IBIS Users: A new Version of ibischk2+ executables is now available on vhdl.org under /pub/ibis/ibschk2+. They are designated Version2.1.4. The new versions replace the Version2.1.3 executables that were stored in the respective operating system directories. The new versions make the Open_* device Waveform endpoint testing more robust. They also issue warnings if [Pullup] or [Pulldown] tables which are expected to contain values of 0 or not exist actually contain other numerical values. Thanks to Chris Rokusek of Quad Design/Viewlogic for making these fixes. Bob Ross Interconnectix From owner-ibis Wed May 21 05:57:47 1997 Received: from mail11.digital.com (mail11.digital.com [192.208.46.10]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id FAA18532 for ; Wed, 21 May 1997 05:57:46 -0700 (PDT) Received: from us8rmc.bb.dec.com by mail11.digital.com (8.7.5/UNX 1.5/1.0/WV) id IAA27751; Wed, 21 May 1997 08:30:09 -0400 (EDT) Received: from wrksys.enet by us8rmc.bb.dec.com (5.65/rmc-17Jan97) id AA11021; Wed, 21 May 97 08:30:45 -0400 Message-Id: <9705211230.AA11021@us8rmc.bb.dec.com> Received: from wrksys.enet; by us8rmc.enet; Wed, 21 May 97 08:31:00 EDT Date: Wed, 21 May 97 08:31:00 EDT From: Andy Ingraham 21-May-1997 0823 To: mail11:;;@us8rmc.bb.dec.com@us8rmc.bb.dec.com@unknown.domain (us8rmc::"roland@sfu.ca roland james chang") Cc: ibis-users@vhdl.org, ingraham@wrksys.ENET.dec.com Apparently-To: ibis-users@vhdl.org, roland@sfu.ca (roland james chang) Subject: Re: SPICE Convergence Tricks - Consequences? Roland Chang asked: > Many people mentioned that convergence problems are quite common, I would > like to know how common are they? Depends greatly on the semiconductor models, and on whose SPICE you are using. Everyone gets them eventually. > Furthermore, I am curious if anyone has a convergence fix that works > everytime, as it seems tedious to try to get things to converge everytime > just by trial and error fixes. You will never find a magic fix that works every time. Well, I suppose you could fully relax ABSTOL and the other *TOL parameters to the point that SPICE just doesn't care about accuracy anymore; but even then it might have convergence problems of a different nature. There are all sorts of things lurking in SPICE simulations that cause misconvergence. Some may be called bugs in SPICE itself, or in the semiconductor model equations and algorithms (such as discontinuities in the formulas). Others are artifacts of how we discretely sample a continuous world, and how computers manipulate data. Generally speaking, though, a few convergence tricks may work for most problems you encounter with one set of semiconductor models. Now if your simulations involve models from several different vendors, then SPICE may keep you on your toes. > Also, what kinds of side-effects, or problems (in terms of IBIS > modelling) have people encountered by forcing the analysis to converge via > fancy SPICE tricks? A general observation, not specific to IBIS modeling: The results of ANY SPICE simulation are never gospel. Whether you use no "tricks" or you use several, the results are just as circumspect. Helping SPICE converge can make its results more accurate, or less accurate. (Relaxing ABSTOL by orders of magnitude probably does not make it more accurate.) I have had SPICE simulations that converged to the wrong result (off by several volts!), when no "tricks" were used. Some of these "tricks" are already built into SPICE itself. The SPICE developers tailored its algorithms and parameters to give reasonable results over a set of benchmark circuits they had. The small resistor in series with voltage sources is already used by SPICE to aid convergence when you force initial conditions via the .NODESET or .IC statements. > One last question regards clarification about typ, min, and max > curves. When one is generating curves for the typical case, > suppose the typical case passes but both the min and max fail, the columns > should read NA for min and max right? Now should I go back and try to > tweak the min and max to converge? OR are some curves meant to only work > for the typical case? Min and max curves ought to represent the extremes of what your device will do. If you can't get these by measurement or simulation, and you care about having a model that shows those extremes, you need to approximate, by whatever means possible. If the best you can do is to shift the typ curves some amount, up/down/left/right, it'll do. Personally, I'd try to get the simulations to work. Maybe this problem points to something fundamentally wrong with the models themselves, which could make even the typ curves wrong. Regards, Andy Ingraham From owner-ibis Wed May 21 11:32:07 1997 Received: from netcomsv.netcom.com (uucp6.netcom.com [163.179.3.6]) by server.vhdl.org (8.8.5/8.8.3) with SMTP id LAA23585 for ; Wed, 21 May 1997 11:32:06 -0700 (PDT) Received: from symdes.UUCP by netcomsv.netcom.com with UUCP (8.6.12/SMI-4.1) id LAA02524; Wed, 21 May 1997 11:00:36 -0700 Received: from taress.symmetry by symmetry.com (4.1/SMI-4.1) id AA29225; Wed, 21 May 97 10:18:45 PDT Date: Wed, 21 May 97 10:18:45 PDT From: zheng@symmetry.com (Zheng SHI) Message-Id: <9705211718.AA29225@ symmetry.com> To: roland@sfu.ca, ingraham@wrksys.enet.dec.com Subject: Re: SPICE Convergence Tricks - Consequences? Cc: ibis-users@vhdl.org in my experince, the convergence problems are often caused by the SPICE models of the clamping diodes, which have ideal value RS=0. because the I/V curve of the diodes is a pure exp() function, SPICE doesn't converge with the extreme large diode current, for example, 1e+20A. o VCC | ----- / \ <-------RS=0 /___\ I/O port | o---------o <------Voltage Range:(-2*Vpower to +2*Vpower) | ----- / \ <-------RS=0 /___\ | | o VEE or GND From owner-ibis Wed May 28 17:24:17 1997 Received: from procyon.pmc-sierra.bc.ca (procyon.pmc-sierra.bc.ca [134.87.115.1]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id RAA14204; Wed, 28 May 1997 17:24:15 -0700 (PDT) Received: from nt-server1.pmc-sierra.bc.ca (nt-server1.pmc-sierra.bc.ca [134.87.116.185]) by procyon.pmc-sierra.bc.ca (8.7.5/8.7.3) with SMTP id RAA16525; Wed, 28 May 1997 17:23:20 -0700 (PDT) Received: by nt-server1.pmc-sierra.bc.ca with SMTP (Microsoft Exchange Server Internet Mail Connector Version 4.0.994.63) id <01BC6B8B.EB69FFF0@nt-server1.pmc-sierra.bc.ca>; Wed, 28 May 1997 17:23:55 -0700 Message-ID: From: Roland Chang To: "'ibis-users@vhdl.org'" , "'ibis-info@vhdl.org'" Subject: RE: S2ibis2 -- inputs with pull-up resistors, bi-directionals, Rising Waveforms, Falling Waveforms, etc. Date: Wed, 28 May 1997 17:23:54 -0700 X-Mailer: Microsoft Exchange Server Internet Mail Connector Version 4.0.994.63 MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Hello, I need some help clarifying the creation of models in IBIS. 1. Inputs with pull-up resistors? Are these treated in any special way? (ie: different than that of a normal input pin?) 2. Bi-directionals? I have a pad structure that has the following nodes: Pad (the output) Oen (ouput enable) In (feeds the output when output enable is asserted, and Pad functions as an output) Cin (feeds the core when output enable is deasserted, and Pad functions as an input) What is the proper way of setting this up in s2ibis2? 3. Rising and Falling Waveforms. I understand that these are supposed to describe the rising and falling edge waveforms of a driver, yet they are not required. There is also a note in the IBISv2.1 specification that states: "...A maximum of 100 waveform tables are allowed per model. Note that for backwards compatibility, the existing [Ramp] keyword is still required. The data in the waveform table is taken with the effects of the C_comp parameter included..." From this, I was wondering, what would having 100 waveform tables be used for? Further, are the Rising and Falling Waveforms somehow a - replacement - for the [Ramp] keyword? Are the Rising and Falling waveforms usually generated in the lab at the bench, or can they be simulated? When are they required, if at all? 4. Analog and Digital VDD's and VSS's. In the spice netlists of the files that I am dealing with, I often multiple VDD's, for example, VDDac, and VDDdc, which are used to power up separately the I/O ring and the core. Has anyone else out there had to deal with multiple VDD's like this? (I'm not talking about multiple VDD's such as 3.3 and 5 V, such that can be solved using pin mapping) 5. Stimulus input voltage risetime and falltimes How are these parameters used? And for what curves are they used for? Clarification of any of the above questions (1-5) would be greatly appreciated, Thanx! Best Regards, Roland *********************************************************************** ** *Roland Chang | email: roland@sfu.ca * *Simon Fraser University | OR * *School of Engineering Science | chang@pmc-sierra.bc.ca * *3rd year Computer Engineering Option | * *********************************************************************** ** ~ From owner-ibis Thu May 29 15:12:40 1997 Received: from icx.com (root@fw.icx.com [205.238.6.33]) by server.vhdl.org (8.8.5/8.8.3) with SMTP id PAA03933 for ; Thu, 29 May 1997 15:12:37 -0700 (PDT) Received: by icx.com (/\oo/\ Smail3.1.29.1 #29.2) id ; Thu, 29 May 97 15:11 PDT Received: by icx.com (/\==/\ Smail3.1.28.1 #28.14) id ; Thu, 29 May 97 15:11 PDT Received: by icx.com (/\==/\ Smail3.1.28.1 #28.14) id ; Thu, 29 May 97 15:11 PDT Message-Id: Date: Thu, 29 May 97 15:11 PDT From: bob@icx.com ( Bob Ross) To: roland_chang@pmc-sierra.bc.ca Subject: RE: S2ibis2 -- inputs with pull-up resistors, bi-directionals, Rising Waveforms, Falling Waveforms, etc. Cc: ibis-users@vhdl.org Roland: You have raised some good questions. I have put some responses to your questions in your text. Best Regards, Bob Ross Interconnectix > To: "'ibis-users@vhdl.org'" , > "'ibis-info@vhdl.org'" > > Subject: RE: S2ibis2 -- inputs with pull-up resistors, bi-directionals, Rising Waveforms, Falling Waveforms, etc. > Date: Wed, 28 May 1997 17:23:54 -0700 > Hello, > I need some help clarifying the creation of models in IBIS. > 1. Inputs with pull-up resistors? > Are these treated in any special way? (ie: different than that of a > normal input pin?) Pullup resistors would appear in the Clamps. They are not separated out. So there is probable that they will be double counted. For Pullups, the contribution in the [Gnd Clamp] table should be should be subtracted. The [Power Clamp] table should be extended to from 0 to Vcc (and possibly linearly extrapolated to 2Vcc) to provide the separate Pullup resistor component. > 2. Bi-directionals? > I have a pad structure that has the following nodes: > Pad (the output) > Oen (ouput enable) > In (feeds the output when output enable is asserted, and Pad functions > as an output) > Cin (feeds the core when output enable is deasserted, and Pad > functions as an input) > What is the proper way of setting this up in s2ibis2? I would need to see the circuit (and documentation, if any) to understand better how to set this up. My first idea would be to tie Cin to any load such as 50 ohms to ground. I would use In as the Input node and model the Pad as an I/O. > 3. Rising and Falling Waveforms. > I understand that these are supposed to describe the rising and > falling edge waveforms of a driver, yet they are not required. There > is also a note in the IBISv2.1 specification that states: "...A > maximum of 100 waveform tables are allowed per model. Note that for > backwards compatibility, the existing [Ramp] keyword is still > required. The data in the waveform table is taken with the effects of > the C_comp parameter included..." > >From this, I was wondering, what would having 100 waveform tables be > used for? I doubt if 100 waveforms is useful, but there was no reason to set a lower limit which may conflict with an unanticipated need. In most cases one or two waveforms is sufficient, and some others might be provided to document the response for a particular set of loads. Several simulators will use at most only two of the waveforms that are provided. Further, are the Rising and Falling Waveforms somehow a - > replacement - for the [Ramp] keyword? The Waveforms replace the [Ramp] keyword. Sometimes waveform data is bad or several waveforms are inconsistent. The [Ramp] keyword is provided so that the user can get still use the model and get a response. Are the Rising and Falling > waveforms usually generated in the lab at the bench, or can they be > simulated? When are they required, if at all? Waveforms are never required. They can be obtained from simulation or from the lab. There are some situations where the waveform response gives a better model because it allows getting data that is closer to the actual loading conditions of the buffer. GTL is an example where the loading conditions are, for example 25 ohms to 1.2 V, even though the Open_drain buffer is powered by a 3.3 V supply - Implying that the Ramp load is connected to 3.3 V. > 4. Analog and Digital VDD's and VSS's. > In the spice netlists of the files that I am dealing with, I often > multiple VDD's, for example, VDDac, and VDDdc, which are used to > power up separately the I/O ring and the core. Has anyone else out > there had to deal with multiple VDD's like this? (I'm not talking > about multiple VDD's such as 3.3 and 5 V, such that can be solved > using pin mapping) The IBIS model does not go into this detail. I would apply the same voltage on all Vdd's to derive the IBIS model. > 5. Stimulus input voltage risetime and falltimes > How are these parameters used? And for what curves are they used > for? The default is 0.1ns. For very fast devices, even this may be too slow. In general, I have seen negligible variation in the output response due to input rise and fall times. However, someone may still want to generate a model response based on an anticipated or data book specified input response time of 2 or 3 ns, for example. > Clarification of any of the above questions (1-5) would be greatly > appreciated, > Thanx! > Best Regards, > Roland > *********************************************************************** > ** > *Roland Chang | email: roland@sfu.ca > * > *Simon Fraser University | OR > * > *School of Engineering Science | chang@pmc-sierra.bc.ca > * > *3rd year Computer Engineering Option | > * > *********************************************************************** > ** > ~ From owner-ibis Fri May 30 12:28:07 1997 Received: from guelah.nexen.com (guelah.nexen.com [204.249.96.19]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id MAA04240 for ; Fri, 30 May 1997 12:28:04 -0700 (PDT) Received: from maelstrom.nexen.com (maelstrom.nexen.com [204.249.98.5]) by guelah.nexen.com (8.8.5/8.7.3) with ESMTP id PAA05432 for ; Fri, 30 May 1997 15:26:32 -0400 (EDT) Received: from asterix.nexen.com (asterix.nexen.com [204.249.99.31]) by maelstrom.nexen.com (8.8.5/8.7.3) with ESMTP id PAA28381 for ; Fri, 30 May 1997 15:26:33 -0400 (EDT) Received: (from jsabuda@localhost) by asterix.nexen.com (8.7.3/8.7.3) id PAA03311 for ibis-users@vhdl.org; Fri, 30 May 1997 15:26:32 -0400 (EDT) Date: Fri, 30 May 1997 15:26:32 -0400 (EDT) From: "Jeffrey A. Sabuda" Message-Id: <199705301926.PAA03311@asterix.nexen.com> To: ibis-users@vhdl.org subscribe From owner-ibis Fri May 30 12:29:51 1997 Received: from guelah.nexen.com (guelah.nexen.com [204.249.96.19]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id MAA04256 for ; Fri, 30 May 1997 12:29:50 -0700 (PDT) Received: from maelstrom.nexen.com (maelstrom.nexen.com [204.249.98.5]) by guelah.nexen.com (8.8.5/8.7.3) with ESMTP id PAA05448 for ; Fri, 30 May 1997 15:28:31 -0400 (EDT) Received: from bach.nexen.com (bach.nexen.com [204.249.99.107]) by maelstrom.nexen.com (8.8.5/8.7.3) with ESMTP id PAA28408 for ; Fri, 30 May 1997 15:28:32 -0400 (EDT) Received: (from chang@localhost) by bach.nexen.com (8.7.3/8.7.3) id PAA04834; Fri, 30 May 1997 15:28:32 -0400 (EDT) Date: Fri, 30 May 1997 15:28:32 -0400 (EDT) From: Luke Chang Message-Id: <199705301928.PAA04834@bach.nexen.com> To: ibis-users@vhdl.org Cc: hamp@nexen.com Hi, When IC vendors create IBIS models for their components, how do they verify whether they are correct or not, compared to either the original SPICE models or to physical measurement data? Do they actually do this comparison? Is there a simulation methodology to do this comparison? I am just a user of IBIS models and will never create them. So I am mainly interested in knowing whether I can always (blindly) trust the models I get from the vendor Web sites or directly from the vendors. Thanks. Luke Chang Ascom Nexion, Inc. Acton, MA From owner-ibis Fri May 30 13:27:06 1997 Received: from relayhost.vlsi.com (tweety.vlsi.com [134.27.20.23]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id NAA04441 for ; Fri, 30 May 1997 13:27:05 -0700 (PDT) Received: from relayhost.tempe.vlsi.com (anubis.tempe.vlsi.com [134.27.128.1]) by relayhost.vlsi.com (8.6.12/Hub-Perlotto/050895) with ESMTP id OAA19874 for ; Fri, 30 May 1997 14:39:36 -0700 Received: from mailserver.tempe.vlsi.com (mailserver.tempe.vlsi.com [134.27.128.5]) by relayhost.tempe.vlsi.com (8.6.9/Hub-Perlotto/101195) with ESMTP id NAA16863 for ; Fri, 30 May 1997 13:25:48 -0700 Received: from witsend ([134.27.133.12]) by mailserver.tempe.vlsi.com (Netscape Mail Server v2.02) with SMTP id AAA24413; Fri, 30 May 1997 13:10:57 -0700 Sender: dc.sessions@tempe.vlsi.com (D.C. Sessions) Message-ID: <338F3451.419F@tempe.vlsi.com> Date: Fri, 30 May 1997 13:10:57 -0700 From: "D. C. Sessions" Organization: VLSI Technology Inc. X-Mailer: Mozilla 3.0Gold (X11; I; SunOS 5.5.1 sun4m) MIME-Version: 1.0 To: Luke Chang CC: ibis-users@vhdl.org Subject: Re: Verifying IBIS models References: <199705301928.PAA04834@bach.nexen.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Luke Chang wrote: > When IC vendors create IBIS models for their components, how do they > verify whether they are correct or not, compared to either the original > SPICE models or to physical measurement data? Do they actually do this > comparison? Is there a simulation methodology to do this comparison? > > I am just a user of IBIS models and will never create them. So I am > mainly interested in knowing whether I can always (blindly) trust the > models I get from the vendor Web sites or directly from the vendors. I suppose the usual disclaimers (I can't, strictly speaking, speak for VLSI, much less other manufacturers) are in order. That said, here's a little about our approach: 1) We SPICE the dickens out of I/O designs. 2) We verify the SPICE characteristics in design validation and test against them. 3) We generate IBIS models from the SPICE models. 4) We spot-compare SPICE simulations made from hand-translating IBIS back to SPICE. We're in the process of converting the canonical model for testing purposes from old-fashioned data sheets to IBIS. We *intensely* wish we had a working IBIS-to-SPICE translator that we could use for closing the loop, but at present there don't seem to be any around. -- D. C. Sessions dc.sessions@tempe.vlsi.com From owner-ibis Fri May 30 13:30:34 1997 Received: from marceau.fm.intel.com (marceau.fm.intel.com [132.233.247.8]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id NAA04477 for ; Fri, 30 May 1997 13:30:29 -0700 (PDT) Received: from fmmail.fm.intel.com by marceau.fm.intel.com (8.8.4/10.0i); Fri, 30 May 1997 20:29:33 GMT Received: (from ccmgate@localhost) by fmmail.fm.intel.com (8.8.5/8.7.3) id NAA02366; Fri, 30 May 1997 13:29:22 -0700 (PDT) Received: by ccm.fm.intel.com (ccmgate 3.2 #2) Fri, 30 May 97 13:29:22 PDT Date: Fri, 30 May 97 13:22:00 PDT From: Arpad Muranyi Message-ID: To: ibis-users@vhdl.org cc: hamp@nexen.com Subject: Re: Text item: Luke, We do test our IBIS models. This is done by comparing the I-V curves with SPICE simulated and/or lab measured curves. We also check the edge rate by comparing the output waveform with SPICE and/or lab waveforms under the same loading conditions. Arpad Muranyi Intel Corporation ============================================================================== Hi, When IC vendors create IBIS models for their components, how do they verify whether they are correct or not, compared to either the original SPICE models or to physical measurement data? Do they actually do this comparison? Is there a simulation methodology to do this comparison? I am just a user of IBIS models and will never create them. So I am mainly interested in knowing whether I can always (blindly) trust the models I get from the vendor Web sites or directly from the vendors. Thanks. Luke Chang Ascom Nexion, Inc. Acton, MA Text item: External Message Header The following mail header is for administrative use and may be ignored unless there are problems. ***IF THERE ARE PROBLEMS SAVE THESE HEADERS***. Cc: hamp@nexen.com To: ibis-users@vhdl.org Message-Id: <199705301928.PAA04834@bach.nexen.com> From: Luke Chang Date: Fri, 30 May 1997 15:28:32 -0400 (EDT) Received: (from chang@localhost) by bach.nexen.com (8.7.3/8.7.3) id PAA04834; Fr i, 30 May 1997 15:28:32 -0400 (EDT) Received: from bach.nexen.com (bach.nexen.com [204.249.99.107]) by maelstrom.nex en.com (8.8.5/8.7.3) with ESMTP id PAA28408 for ; Fri, 30 M ay 1997 15:28:32 -0400 (EDT) Received: from maelstrom.nexen.com (maelstrom.nexen.com [204.249.98.5]) by guela h.nexen.com (8.8.5/8.7.3) with ESMTP id PAA05448 for ; Fri, 30 May 1997 15:28:31 -0400 (EDT) Received: from guelah.nexen.com (guelah.nexen.com [204.249.96.19]) by server.vhd l.org (8.8.5/8.8.3) with ESMTP id MAA04256 for ; Fri, 30 Ma y 1997 12:29:50 -0700 (PDT) Received: from server.vhdl.org (server.vhdl.org [198.31.14.3]) by mailbag.jf.intel.com (8.8.5/8.8.4) with ESMTP id MAA04637; Fri, 30 May 1997 12:39:01 -0700 (PDT) Received: from mailbag.jf.intel.com by relay.hf.intel.com with smtp (Smail3.1.28.1 #2) id m0wXXUx-000qDJC; Fri, 30 May 97 12:38 PDT From owner-ibis Fri May 30 13:52:38 1997 Received: from ormail.intel.com (ormail.intel.com [134.134.248.3]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id NAA04576 for ; Fri, 30 May 1997 13:52:37 -0700 (PDT) Received: from ichips.intel.com (ichips.intel.com [134.134.50.200]) by ormail.intel.com (8.8.4/8.8.4) with ESMTP id NAA02007; Fri, 30 May 1997 13:51:18 -0700 (PDT) Received: from ichips.intel.com by ichips.intel.com (8.7.4/jIII) id NAA24075; Fri, 30 May 1997 13:51:33 -0700 (PDT) Message-Id: <199705302051.NAA24075@ichips.intel.com> To: ibis-users@vhdl.org Cc: hamp@nexen.com Subject: In models we trust Date: Fri, 30 May 1997 13:51:33 -0700 From: Stephen Peters Hello Luke: Well, first off, I would never "blindly" trust ANY model -- spice, IBIS, or otherwise. Remember that all models are accurate only over a given environment/operating range, and a model may only be good for a specific kind of simulation. For example, a model created for signal integrety work is probably not approriate for doing EM simulations. Before using any model one must understand it's purpose and the conditions under which it gives accurate results. To answer your specific question -- the model vendor is responsible for verifing the data in, and results obtained from, an IBIS model. The IBIS forum does make sure that the model passes the golden parser before it's placed on our web site, but we don't have the capabilites to verify that the model gives "good results". If you have questions about a specific model you should contact the model supplier directly. Regards, Stephen Peters Intel Corp. Hi, When IC vendors create IBIS models for their components, how do they verify whether they are correct or not, compared to either the original SPICE models or to physical measurement data? Do they actually do this comparison? Is there a simulation methodology to do this comparison? I am just a user of IBIS models and will never create them. So I am mainly interested in knowing whether I can always (blindly) trust the models I get from the vendor Web sites or directly from the vendors. Thanks. Luke Chang Ascom Nexion, Inc. Acton, MA From owner-ibis Fri May 30 14:40:28 1997 Received: from natsemi-bh.nsc.com (natsemi-bh.nsc.com [204.163.202.66]) by server.vhdl.org (8.8.5/8.8.3) with SMTP id OAA04734 for ; Fri, 30 May 1997 14:40:27 -0700 (PDT) Received: (from uucp@localhost) by natsemi-bh.nsc.com (8.6.12/8.6.11) id OAA07871; Fri, 30 May 1997 14:38:28 -0700 Received: from nsc.nsc.com by natsemi-bh.nsc.com via smap (3.2) id xma007437; Fri, 30 May 97 14:38:02 -0700 Received: from lightning.nsc.com by nsc.nsc.com (5.65/1.34) with SMTP id AA02841 for ibis-users@vhdl.org; Fri, 30 May 97 14:38:59 -0700 Received: from kural by rockie.nsc.com (4.1/SMI-4.1) id AA01086; Fri, 30 May 97 14:42:41 PDT Date: Fri, 30 May 97 14:42:41 PDT From: huq@rockie.nsc.com (Syed Huq) Message-Id: <9705302142.AA01086@rockie.nsc.com> To: ibis-users@vhdl.org, chang@nexen.com Subject: Re: Cc: hamp@nexen.com Luke, At National Semiconductor, we are generating IBIS models either from bench measurements or from SPICE simulations. It depends which product lines the models are generated from. In either case, the final IBIS model is run on two seperate EDA tools that support the IBIS format. Measurements made on IBIS simulation are compared against bench data or SPICE runs for validation process. Regards, Syed National Semiconductor. > From owner-ibis@server.vhdl.org Fri May 30 13:36:58 1997 > Date: Fri, 30 May 1997 15:28:32 -0400 (EDT) > From: Luke Chang > To: ibis-users@vhdl.org > Cc: hamp@nexen.com > > Hi, > > When IC vendors create IBIS models for their components, how do they > verify whether they are correct or not, compared to either the original > SPICE models or to physical measurement data? Do they actually do this > comparison? Is there a simulation methodology to do this comparison? > > I am just a user of IBIS models and will never create them. So I am > mainly interested in knowing whether I can always (blindly) trust the > models I get from the vendor Web sites or directly from the vendors. > > Thanks. > > Luke Chang > Ascom Nexion, Inc. > Acton, MA > From owner-ibis Fri May 30 14:44:04 1997 Received: from mail13.digital.com (mail13.digital.com [192.208.46.30]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id OAA04743 for ; Fri, 30 May 1997 14:44:03 -0700 (PDT) Received: from us8rmc.bb.dec.com by mail13.digital.com (8.7.5/UNX 1.5/1.0/WV) id RAA09592; Fri, 30 May 1997 17:34:46 -0400 (EDT) Received: from wrksys.enet by us8rmc.bb.dec.com (5.65/rmc-17Jan97) id AA17643; Fri, 30 May 97 17:32:53 -0400 Message-Id: <9705302132.AA17643@us8rmc.bb.dec.com> Received: from wrksys.enet; by us8rmc.enet; Fri, 30 May 97 17:34:54 EDT Date: Fri, 30 May 97 17:34:54 EDT From: Andy Ingraham To: chang@nexen.com Cc: ibis-users@vhdl.org, ingraham@wrksys.ENET.dec.com Apparently-To: ibis-users@vhdl.org, chang@nexen.com Subject: Verifying and trusting models Luke Chang wrote: > I am just a user of IBIS models and will never create them. So I am > mainly interested in knowing whether I can always (blindly) trust the > models I get from the vendor Web sites or directly from the vendors. Whether it is an IBIS model or a SPICE model, it is wise to always (blindly) distrust the models you get. Chances are, there is something grossly wrong with the model. I have received models that went through lengthy testing before being released to me, yet they were rather obviously wrong. Just today I am looking at a vendor's SPICE model that has been available for at least six months, yet it's wrong. Fortunately there happens to be a second model to compare it against, or I might have never known. Kind of a sad situation, wouldn't you say? Regards, Andy From owner-ibis Fri May 30 15:10:51 1997 Received: from cliff.molex.com ([209.28.10.2]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id PAA04829; Fri, 30 May 1997 15:10:49 -0700 (PDT) From: apanella@molex.com Received: from cliff (localhost [127.0.0.1]) by cliff.molex.com (8.7.3 Version 1.1 Build 563/8.7.3) with SMTP id RAA00152; Fri, 30 May 1997 17:13:13 -0500 (Central Daylight Time) Date: 30 May 97 17:05 CDT X400-Received: by /PRMD=molex/ADMD=molexnet/C=us/; Relayed; 30 May 97 17:05 CDT X400-Received: by mta "molexmta" in /PRMD=molex/ADMD=molexnet/C=us/; Relayed; 30 May 97 17:13 CDT Priority: normal P1-Message-ID: us*molexnet*molex;0865030389/0000002181/1 Original-Encoded-Information-Types: IA5-Text MIME-version: 1.0 To: ibis-users@vhdl.org, owner-ibis@server.vhdl.org Message-ID: <0865030389/0000011577/1*@cliff.molex.com> Subject: Re: In models we trust Hello all, Good comments Stephan!!! But it does bring up the question.... Who verifies the performance of the simulation vendors products? My understanding (specifcally in regards to the potential connectors models), that it is possible for each simulation vendors product to handle passive models fdifferently. Therefore, a model I create for one IBIS model solver will look differently on othe IBIS solvers. I would not want to be required to make a different passive component (ie connector model) for each IBIS simulation vendor. Comments?? Regards, _gus panella molex, incorporated apanella@molex.com ______________________________ Reply Separator _________________________________ Subject: In models we trust Author: owner-ibis@server.vhdl.org at internet Date: 97/05/30 1:51 PM Hello Luke: Well, first off, I would never "blindly" trust ANY model -- spice, IBIS, or otherwise. Remember that all models are accurate only over a given environment/operating range, and a model may only be good for a specific kind of simulation. For example, a model created for signal integrety work is probably not approriate for doing EM simulations. Before using any model one must understand it's purpose and the conditions under which it gives accurate results. To answer your specific question -- the model vendor is responsible for verifing the data in, and results obtained from, an IBIS model. The IBIS forum does make sure that the model passes the golden parser before it's placed on our web site, but we don't have the capabilites to verify that the model gives "good results". If you have questions about a specific model you should contact the model supplier directly. Regards, Stephen Peters Intel Corp. Hi, When IC vendors create IBIS models for their components, how do they verify whether they are correct or not, compared to either the original SPICE models or to physical measurement data? Do they actually do this comparison? Is there a simulation methodology to do this comparison? I am just a user of IBIS models and will never create them. So I am mainly interested in knowing whether I can always (blindly) trust the models I get from the vendor Web sites or directly from the vendors. Thanks. Luke Chang Ascom Nexion, Inc. Acton, MA From owner-ibis Fri May 30 15:36:21 1997 Received: from mailgate.cadence.com (mailgate.Cadence.COM [158.140.2.1]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id PAA05400; Fri, 30 May 1997 15:36:21 -0700 (PDT) Received: (from smap@localhost) by mailgate.cadence.com (8.8.5/8.6.8) id PAA12303; Fri, 30 May 1997 15:35:23 -0700 (PDT) Received: from hot.cadence.com(158.140.103.49) by mailgate.cadence.com via smap (V1.0mjr) id sma865031721.012283; Fri May 30 15:35:21 1997 Received: (from cpk@localhost) by hot (8.6.8/8.6.8) id SAA17026; Fri, 30 May 1997 18:35:19 -0400 Date: Fri, 30 May 1997 18:35:19 -0400 From: "C. Kumar" Message-Id: <199705302235.SAA17026@hot> To: ibis-users@vhdl.org, owner-ibis@server.vhdl.org, apanella@molex.com Subject: Re: In models we trust X-Sun-Charset: US-ASCII Passsive models should yield identical results in different simulators. Only in active models (IBIS buffers) there may be differences due to interpolation/extrapolation schemes. > From owner-ibis@server.vhdl.org Fri May 30 18:23 EDT 1997 > Received-Date: Fri, 30 May 1997 18:23:00 -0400 > From: apanella@molex.com > X400-Received: by /PRMD=molex/ADMD=molexnet/C=us/; > Relayed; 30 May 97 17:05 CDT > X400-Received: by mta "molexmta" in /PRMD=molex/ADMD=molexnet/C=us/; > Relayed; 30 May 97 17:13 CDT > Priority: normal > P1-Message-ID: us*molexnet*molex;0865030389/0000002181/1 > Original-Encoded-Information-Types: IA5-Text > MIME-version: 1.0 > To: ibis-users@vhdl.org, owner-ibis@server.vhdl.org > Subject: Re: In models we trust > Content-Type: text > Content-Length: 2529 > X-Lines: 72 > > Hello all, > > Good comments Stephan!!! > > But it does bring up the question.... > > Who verifies the performance of the simulation vendors products? > > > My understanding (specifcally in regards to the potential connectors > models), that it is possible for each simulation vendors product to > handle passive models fdifferently. > > Therefore, a model I create for one IBIS model solver will look > differently on othe IBIS solvers. > > I would not want to be required to make a different passive component > (ie connector model) for each IBIS simulation vendor. > > Comments?? > > Regards, > _gus panella > molex, incorporated > apanella@molex.com > > > ______________________________ Reply Separator _________________________________ > Subject: In models we trust > Author: owner-ibis@server.vhdl.org at internet > Date: 97/05/30 1:51 PM > > > Hello Luke: > > Well, first off, I would never "blindly" trust ANY model -- spice, > IBIS, or otherwise. Remember that all models are accurate only over > a given environment/operating range, and a model may only be good > for a specific kind of simulation. For example, a model created > for signal integrety work is probably not approriate for doing EM > simulations. Before using any model one must understand it's > purpose and the conditions under which it gives accurate results. > > To answer your specific question -- the model vendor is responsible > for verifing the data in, and results obtained from, an IBIS model. The IBIS > forum does make sure that the model passes the golden parser before > it's placed on our web site, but we don't have the capabilites to verify > that the model gives "good results". If you have questions about a specific > model you should contact the model supplier directly. > > Regards, > Stephen Peters > Intel Corp. > > > > Hi, > > When IC vendors create IBIS models for their components, how do they > verify whether they are correct or not, compared to either the original > SPICE models or to physical measurement data? Do they actually do this > comparison? Is there a simulation methodology to do this comparison? > > I am just a user of IBIS models and will never create them. So I am > mainly interested in knowing whether I can always (blindly) trust the > models I get from the vendor Web sites or directly from the vendors. > > Thanks. > > Luke Chang > Ascom Nexion, Inc. > Acton, MA > From owner-ibis Fri May 30 17:32:57 1997 Received: from relay5.UU.NET (relay5.UU.NET [192.48.96.15]) by server.vhdl.org (8.8.5/8.8.3) with ESMTP id RAA07352 for ; Fri, 30 May 1997 17:32:56 -0700 (PDT) Received: from uucp3.UU.NET by relay5.UU.NET with SMTP (peer crosschecked as: uucp3.UU.NET [192.48.96.34]) id QQcrvm26641; Fri, 30 May 1997 20:32:22 -0400 (EDT) Received: from qdt.UUCP by uucp3.UU.NET with UUCP/RMAIL ; Fri, 30 May 1997 20:32:03 -0400 Received: from hal.qdt.com by qdt.com (4.1/SMI-4.1) id AA02214; Fri, 30 May 97 17:12:11 PDT Received: from qdt.com by hal.qdt.com (4.1/SMI-4.1) id AA12461; Fri, 30 May 97 17:12:05 PDT Received: from uucp1.UU.NET by relay5.UU.NET with SMTP (peer crosschecked as: uucp1.UU.NET [192.48.96.39]) id QQcrvi12047; Fri, 30 May 1997 19:33:57 -0400 (EDT) Received: from qdt.UUCP by uucp1.UU.NET with UUCP/RMAIL ; Fri, 30 May 1997 19:33:39 -0400 Received: from hal.qdt.com by qdt.com (4.1/SMI-4.1) id AA02127; Fri, 30 May 97 16:31:57 PDT Received: from f14 by hal.qdt.com (4.1/SMI-4.1) id AA12203; Fri, 30 May 97 16:31:55 PDT Sender: uunet!qdt.com!jonp@uunet.uu.net Message-Id: <338F631D.7991A45@qdt.com> Date: Fri, 30 May 1997 16:30:37 -0700 From: Jon Powell X-Mailer: Mozilla 3.0Gold (X11; I; SunOS 4.1.4 sun4m) Mime-Version: 1.0 To: Luke Chang Cc: uunet!uunet!vhdl.org!ibis-users@uunet.uu.net, uunet!uunet!nexen.com!hamp@uunet.uu.net Subject: Re: Model Accuracy References: <199705301928.PAA04834@bach.nexen.com> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit The actual IBIS party line is (well, might be): All models are always right, however it is astonishing how often they point to actual design errors in the silicon.... :) jon From owner-ibis Fri May 30 19:54:02 1997 Received: from lms02.us1.ibm.com (lms02.ny.us.ibm.com [198.133.29.70]) by server.vhdl.org (8.8.5/8.8.3) with SMTP id TAA09669 for ; Fri, 30 May 1997 19:54:01 -0700 (PDT) Received: from d01lms04.pok.ibm.com by lms02.us1.ibm.com (AIX 4.1/UCB 5.64/4.03) id AA07398; Sat, 31 May 1997 02:58:51 GMT Received: by US.IBM.COM (Soft-Switch LMS 2.0) with snapi via D01AU002 id 5010400003673616; Fri, 30 May 1997 22:54:57 -0400 From: Joe Cahill To: Subject: Re: model accuracy Message-Id: <5010400003673616000002L062*@MHS> Date: Fri, 30 May 1997 22:54:57 -0400 Mime-Version: 1.0 Content-Type: text/plain I believe that the behavior a driver exhibits in an EDA tool's transmission line simulator is a function of both the IBIS model and the tool's IBIS simulation algorithms. The tool must translate the simple data points (I/V and dv/dt tables) in the IBIS model into a complicated and dynamic behavioral interaction with the behavior of the transmission line algorithms in the tool. This is rocket science. There are quite a few transmission line algorithms in use, and quite a few algorithms to get useful behavior from the IBIS model data points. So far we haven't seen much discussion of the accuracy differences between simulators, but I expect that to come as IBIS becomes a commodity. Manufacturers can verify that the I/V curves and dv/dt curves match hardware or spice, manufacturers can build spice models to mimic the IBIS model in spice but unless they check the behavior of the IBIS model on a few diverse transmission line networks in several transmission line simulation tools - against spice or hardware - they are essentially only placing the data sheet in electronic form. Unfortunately the form is so useful that you can extrapolate some very realistic behavior form it. Realistic, but not necessarily representative of the manufacturer's hardware. Trust the IBIS model to tell you as much usefull information as the data sheet. Do your own qualification of the transmission line simulator and the IBIS models you wish to use against whatever other, more reliable information you can obtain on a few benchmark networks before you push the edge of your design using them. Joe