Subject: Minutes, IBIS Teleconference Meeting 7/20

From: "Peters, Stephen" <[email-masked]>
Date: Tue, 24 Jul 2001 12:43:34 -0700

DATE: 7/24/01

SUBJECT: 7/20/01 EIA IBIS Open Forum Meeting Minutes

VOTING MEMBERS AND 2001 PARTICIPANTS LIST:
3Com (& CommWorks)             Roy Leventhal*
Ansoft Corporation             (Eric Bracken)
Apple Computer                 John Figueroa
Applied Simulation Technology  [Raj Raghuram], Norio Matsui, Fred Balistreri
Avanti                         (Chen Hongyu)
Cadence Design                 [Ian Dodd], Patrick Dos Santos, Heiko Dudek
                               Lynne Green, Lance Wang
Cisco Systems                  Syed Huq, Lungfu Chen
EMC Corporation                Brian Arsenault, Jinhua Chen
Fairchild Semiconductor        Adam Tambone
Huawei Technologies            Rachild Chen
IBM                            Michael Cohen, Greg Edlund*, Wes Martin,
                               Yeon-Chang Hahm, Bill DeVey, Pravin Patel*
Innoveda (& HyperLynx)         Guy de Burgh, John Angulo*, Cary Mandel, 
                               Matthew Flora, Steve Kaufer
Intel Corporation              Stephen Peters*, Arpad Muranyi*, Dave Lorang,
                               Michael Mirmak, Qinglun Chen, Will Hobbs,
                               Wei-hsing Huang
LSI Logic                      Larry Barnes
Mentor Graphics                Bob Ross*, Tom Dagostino, Chris Reid,
                               Mike Donnelly, Hazem Hegazy, Tony Dunbar,
                               Griff Derryberry, Dan Lake, Sherif Hammad,
                               Mohammed Korany, Weston Beal, Chris Swaim,
                               Ali Samii, Eric Ronger, Karine Loudet,
                               Daisaku Shiga, Kenji Kushima
Micron Technology              Randy Wolff*, Yong Phan*
Mitsubishi                     Pat Hefferan
Molex Incorporated             Gus Panella, Brian O'Malley
National Semiconductor         Milt Schwartz
North East Systems Associates  Edward Sayre
Philips Semiconductor          Zack Ciccone, Rob Mataheroe
Quantic EMC                    (Mike Ventham)
Signal Integrity Software      Douglas Burns, Barry Katz, Walter Katz
SiQual                         Scott McMorrow, Rob Hinz, Bernard Voss,
                               Chris Brewster
Texas Instruments              Thomas Fisher, Stephen Nolan, Ramzi Ammar,
                               Jean Claude Perrin, Moshiul Haque
Time Domain Analysis Systems   Dima Smolyansky, Steve Corey
Tyco Electronics               (Russell Moser)
Via Technologies               (Weber Chuang)
Zuken (& Incases)              John Berrie, Ralf Bruening

OTHER PARTICIPANTS IN 2001:
Actel Corporation              Silvia Montoya
Acuson                         Kim Helliwell
AMCC                           Jeff Smith
ASIS Ltd                       David Wright
Brocade Communications         Robert Badal
BMW                            Friedrich Hasinger
Cereva Networks                Bob Haller
Compaq                         [Peter LaFlamme], Ron Bellomio, Quang Dam,
                               Bill Ham
Cypress                        (Rajesh Manapat)
EADS Airbus Industry           Claude Huet
  (Aerospatiale)
EFM                            Ekkehard Miersch, Horle Raines
EIA                            Cecilia Fleming
Ericsson Radio Systems         Anders Ekholm
FCI                            Sercu Stefaan
Foundary Networks              Bertram Chan
Framatom Conectors             Danny Morlion
Fraunhofer Institute           Mariusz Faferko, Peter Kralicek
  Reliability and
  Integration
Fujitsu Ltd                    Tadashi Arai, Takeshi Murakami
Heidelberger Druchmaschinen AG Wolfgang Kleinfeldt
Hyundai Electronics            Jongho Kang
Idaho State University         Al Davis
Infineon Technologies          Christian Sporrer
Intrinsix Corporation          Steven Chin
Motorola                       (Rick Kingen)
National Institute of Applied  Etienne Sicard
  Science (INSA)
Nokia                          Tapani von Ravner, Mika Castren,
                               Janne Uusitalo
Nortel Networks                Calvin Trowell
Oak Technology                 Darmin Jin
Plexus Technology Group        Joseph Socha
Siemens (& Automotive) AG      Bernhard Unger, Helmut Katzier, Katja Koller,
                               Wolfram Meyer, Eckhard Lenski, Gerald
Bannert,
                               Burkhard Muller, Christian Marot,
                               Manfred Maurer, Amir Motamedi,
                               Hans Pichlmaier
Sigrity                        Raj Raghuram*
Sintecs                        Hans Klos
STMicroelectronics             Peter Hirt, Fabrice Boissieres
Sun                            Adrian Udenze
Toshiba Corp.                  Hirokaza Kato, Yuichi Koga, Toshio Sudo
Xilinx                         Susan Wu

In the list above, attendees at the meeting are indicated by *. Principal
members or other active members who have not attended are in parentheses.
Participants who no longer are in the organization are in square brackets.

Upcoming Meetings:  The bridge numbers for future IBIS teleconferences are
as
follows:

  Date                Bridge Number    Reservation #    Passcode
  August 10           (877) 299-1938   none             6350164    
  August 31           (916) 356-2663   2                4779396  
  Thursday, September 13, 2001 IBIS Summit Meeting, No Phone Bridge

All meetings are 8:00 AM to 9:55 AM Pacific Time.  We try to have agendas
out
7 days before each Open Forum, and meeting minutes out within 7 days after.
When you call into the meeting, ask for the IBIS Open Forum hosted by
Stephen
Peters and give the reservation number and passcode.

NOTE: "AR" = Action Required.

-------------------------------- MINUTES
-------------------------------------
INTRODUCTIONS AND MEETING QUORUM
Raj Raghuram, who has been involved for years with IBIS as a model developer
and as a tool developer joined Sigrity.  Sigrity is involved with power and
signal integrity simulations and uses IBIS models.  Raj stated that Sigrity
plans to become an EIA IBIS Open Forum member.

MEMBERSHIP UPDATE AND TREASURER'S REPORT
Stephen Peters reported about 28-29 members (down from 30) since there were
some payment issues.  These are being resolved.  Bob Ross reported there are
three potential members that are being processed (including Sigrity).  So we
expect about 32 members, ahead of the 30 member target from which our budget
is based.

REVIEW OF MINUTES AND AR'S
The June 01, 2001 IBIS Minutes were approved without change.

Bob Ross submitted a spelling correction for Ralf Bruening of Zuken in the
participants list for the June 21, 2001 IBIS Summit Meeting minutes.  The
Minutes were approved with this change.  Bob stated that the uploaded
minutes
have been corrected.

The ARs will be discussed during the meeting.

MISCELLANY/ANNOUNCEMENTS
Stephen Peters stated that several officers have been on vacation, but are
now
returning.  Guy de Burgh will return after July 27, 2001.

PRESS AND WEB PAGE UPDATES
Stephen Peters reported that Syed Huq made more Roster updates, did an FAQ
update (for ibischk3 source code license purchases), uploaded some IBIS
Summit
presentations, and updated the Upcoming Events link.

NEW MODELS AVAILABLE, LIBRARY UPDATE
Stephen Peters stated that Roy Leventhal provided more updates as of 6/26/01
on the IBIS Models link.

Bob Ross reported that Mindspeed Technologies (a Conexant Business) has IBIS

Models under (URL split into two lines to avoid mailer truncation):

 http://web2.mindspeed.com/default.sph/SaServletEngine.class/Web/products/
      documents.jsp?doc_type=27

OPENS FOR NEW ISSUES
None.

INTERNATIONAL/EXTERNAL PROGRESS
- IEC 62014-1 (IBIS Version 3.2) - No report.  Bob Ross stated that the
  document is probably still in prepublication status.

- pr EIAJ ED-5302 Standard for I/O Interface Model for Integrated Circuits
  (IMIC) - Bob Ross still cannot find the new link to the IMIC document.  

- IEC 62014-3 (ICEM) Integrated Circuit Electromagnetic Model Proposal
  (formerly, IEC 93/67/NP IBIS and EMC Simulation) - Bob Ross stated that 
  Etienne Sicard plans to present work at the September 13, 2001 IBIS Summit
  meeting.  This will be discussed later in the meeting.

- JEDEC JC-16 - Modeling and Testing - No report.

- T10, Project 1414-DT - SCSI Signal Modeling (a Technical Committee of the
  National Committee for Information Technology (NCITS)) - No report.

DESIGN AUTOMATION CONFERENCE 2001 IBIS SUMMIT MEETING FEEDBACK
Stephen Peters enjoyed the meeting.  However, he felt that we did not have
as
many questions and interactions as in some other meetings and is looking for
suggestions for more interactions.  He expected more questions on IBIS-X.
Arpad Muranyi reported that some people discussed things after the meeting, 
but he did not think there was an IBIS-X parser demonstration offered by Al
Davis.  Several people had to catch plane connections after the meeting.

Bob Ross stated that we had more presentations than expected and had to
limit
questions to keep the meeting going.  We did not have copies of all slides
available at the meeting.  The presentations are all now uploaded under:

  http://www.eda.org/pub/ibis/summits/jun01/

PCB CONFERENCE EAST 2001 IBIS SUMMIT MEETING PLANS
Bob Ross reported that an IBIS Summit Meeting is planned all day on
Thursday, 
September 13, 2001 in Worcester, Massachusetts at the Crowne Plaza Hotel
near
the PCB Conference East 2001 show.  The meeting follows on the next day the
trade show portion of the show.  The Upcoming events link of the IBIS Home
page already contains the sign-up information and hotel information.  A free
lunch and refreshments are included.

Kathy Breda of NESA has been handling the arrangements and signups.  She
will
also coordinate making copies of presentations for the meeting.  Bob stated
that we need to address the funding issue.  In the past the EDA vendors have
shared the meeting expenses.

So far Bob expects these presentations (titles may change):

  "Modeling the Radiated Emission of Micro-controllers", Etienne Sicard,
    National Institute of Applied Science (INSA) in France
  "A Proposal for s2ibis3", Michael Steer, North Carolina State University
  
  Plus IBIS Version 4.0, IBIS-X and IBIS Connector Specification Progress

Bob indicated that the IBIS Futures Working Group had discussed
demonstrating
the IBIS-X parser at the Summit meeting.  This follows up on Stephen Peters
comment to make the meeting have more interactive and promote more questions
and discussions.

Bob plans that the first announcement will be sent next week.

NORTH CAROLINA STATE UNIVERSITY S2IBIS3 PROJECT
Stephen Peters reported that he and Michael Steer of North Carolina State
University (NCSU) have made recent contact.  NCSU is working on a cell
design
project under a DARPA contract and is now interested in using IBIS.  Michael
is interested in developing s2ibis3 as part of this research.  His team
would
be interested in using the ibischk3 as a basis, but Stephen stated that NCSU
would have to pay for the source code.  NCSU will probably develop their
own parser independently.

Bob Ross mentioned that NCSU would release s2ibis3 source code and
executables
under a GPL (GNU public license).  Michael Steer is scheduled to discuss the
project at the September 13, 2001 IBIS Summit Meeting.

IBIS MODEL REVIEW COMMITTEE DISCUSSION
John Angulo sent out a model from STMicroelectronics for review.  John also
has two other models that are being processed prior to being distributed.

John stated that he cannot continue heading the IBIS Model Review Committee
because of work commitments.  He suggested several other people.  Stephen
Peters will work offline to find a replacement.

MAJORDOMO AND SPAM MAIL UPDATE
Stephen Peters reported that there seems to be more spam messages on the
IBIS
reflectors.  Possibly someone is harvesting names off the mailing list
(which
is protected) or off of e-mail correspondence.  One solution is to control
the
messages from a list server such as Majordomo.  Using Majordomo, only folks
that
have subscribed and have known valid e-mail addresses could post to the IBIS
reflectors, thus cutting down on SPAM to the list.

John Angulo is still working with the eda.org systems administrators on
using
Majordomo.  John would want to set up a test reflector before we actually
make the change.  There might be more restrictive access.  John also noted
that some of the spam messages have been sent to the ibis-request and
ibis-info addresses.

CONNECTOR PROPOSAL REVIEW
The Working Group has been meet on June 12, July 3, and July 10, 2001.  The
attendance was down because of vacations.  Stephen Peters summarized that
work
is continuing on reviewing the Connector Specification to align it with the
IBIS document and also with some IBIS-X conventions.  This work is
proceeding
more slowly than expected.

Some recent topics include uncoupled and coupled lines, the transmission
line
syntax and frequency dependent matrices.

Bob Ross stated that more people are now involved.  Some earlier decisions
are
subject to review.  The original choices included focusing on connector only
issues versus trying to make this a combined package/connector model
document,
and postponing lossy matrices.  Arpad Muranyi stated that it might not be
difficult to put in frequency dependent matrices.  Bob agreed and stated
that
the earlier consensus continues to implement losses based on matrices as a
function of frequency.  This is a superset of just assuming skin effect and
conductance matrix relationships.

Stephen stated that he preferred using the matrix approach as implemented in
the document and wanted to proceed in a rapid manner to get the Connector
Specification approved by the end of the year.  It has been under
development
for several years.

The next meeting is scheduled on July 24, 2001, and they should continue on
a
weekly basis.

IBIS FUTURES (IBIS-X, API, BIRDxx)
Stephen Peters summarized the progress based on meetings on June 12, July 3,
10 and 17, 2001.  The discussions included the basic elements, some
transmission line syntax (similar to the Connector Specification), LRC
matrix issues and the Laplace element.  John Angulo added that the syntax
for
controlled sources was discussed at the last meeting.

Stephen stated that Scott McMorrow has issued comments on the Connector 
Specification and now is providing good comments on the IBIS futures
documents.

Work is continuing and the next meeting is scheduled for July 24, 2001.
These
should continue on a weekly basis.

BIRD70.3 - GOLDEN WAVEFORMS
Greg Edlund indicated that he put out several messages on the IBIS reflector
in response to comments made at previous meetings.  He got one positive
comment back.

Bob Ross stated that vacations and other IBIS activities prevented him from
looking at BIRD70.3 and Greg's comments until now.  He summarized his
response
as follows:

  He agrees with Issue 1 that a new [Test Data] subparameter
Driver_model_inv
  should be added to support unsymmetrical differential drivers.

  He suggests that [Test Load] should add the subparamater
Receiver_model_inv
  for completeness and to support unsymmetrical receivers with internal 
  terminations.

  Bob noted that the [Test Load] subparameter Test_load_type was incorrectly
  entered as "Test_data_type" in some portions of BIRD70.3.

  Bob agreed with Greg's proposed Issue 2 restriction that only these
  combinations of Test_data_type and Test_load_type would be supported:

     Single_ended, Single_ended
     Differential, Differential

  While the combination Differential, Single_ended is also possible, it is
  not necessary since the Single_ended test load can be created with default
  large values of Rdiff*.  The rules need to be stated for the Single_ended
  case how to interpret the differential golden waveforms [Diff ...] and the
  Rdiff* and *_inv parameters.  Bob proposed that should be ignored.  The
  parser probably would accept the model, but issue an Warning message.

  Finally the single_ended golden waveforms given for Test_data_type
  Differential should be for the non-inverting side of the net when *-inv
  models are used.  The inverting golden waveform data can be obtained by a
  separate test, but with the inverting and non-inverting models
interchanged.
  If the differential network is symmetrical, this is not an issue since the
  inverting and non-inverting models are the same.

Bob plans to respond on the reflector to Greg's e-mail to capture these
points.  Greg should review this and issue BIRD70.4 in time for a vote at
the
next IBIS Meeting.  

AR - Bob Ross respond to Greg Edlunds comments.  Greg issue BIRD70.4 by July
27, 2001 so that it can be presented for a vote at the next IBIS Meeting.

BIRD71 - TIMING TEST LOADS IN [Model Spec] TO SUPPORT PCI & PCI-X
Stephen Peters stated that there have not been any reflector comments on
BIRD71.  BIRD71 completes the list of [Model Spec] subparameters in a manner
that supports PCI and PCI-X specifications.  There have been some concerns
on
how EDA tools should use the new information.

Bob Ross stated that he had questions because some of the new specification
subparameters interacted with the model data itself.  The loads, for example
may be different for the min and max corners.  This does not relate to how
a physical part is specified or measured since the measurement is set up
independent of the electrical characteristics of the component.  So there
may
be some ambiguity on how EDA tools are to process the new subparameters.

One suggestion is that the new subparameters is related to the actual model
corners and are used to set up best and worst cases.  Bob had suggested that
there might be some discussion about on this in BIRD71.  He did not have
specific suggestions.  Bob favors adding the subparameters per BIRD71 and
letting the EDA tools decide how to process the new information.  He will
communicate any new ideas, if any, by next week.

Stephen proposed that BIRD71 be scheduled for a vote at the next meeting.

OTHER PENDING BIRDS
Stephen Peters stated that he wanted IBIS Version 4.0 to be finished soon
and
voted by the end of the year.  Votes are planned for BIRD70.4 and BIRD71.
All
other pending BIRDs need to be issued or deferred until IBIS-X.

Bob stated that the SSO improvement proposal is pending, but might be
deferred
to IBIS-X where structural interactions could be programmed.  This
improvement
may not work in all cases and may open up some technical issues.  A fallback
submodel BIRD is needed for some existing technologies needs to be generated
if it is to be considered.  Bob also stated that a clarification BIRD for
Series Switch models is being developed by Tom Dagostino (following up on
the
Ad Hoc presentation at the June 21, 2001 IBIS Summit Meeting).  This pending
BIRD will make the discussion more general, but will not propose any syntax
change.

IBISCHK3 BUG TRACKING
- BUG57 Non-Mononic Table Causes Waveform Endpoint Test to Fail
  Bob Ross introduced BUG57 by pointing out that if the [Pulldown] and/or
  the [Pullup] table contains non-monotonic data in the clamping regions,
and
  there are no [Gnd Clamp] or [Power Clamp] tables, ibischk3 gives an
  incorrect Error message.  

  The non-monotonic data itself causes ibischk3 to calculate the wrong
  endpoint values because the algorithm probably has numerical difficulties.
  It probably starts its convergence calculation at one end of the table
  rather than from the middle and gets numerically confused with the
  non-monotonic data.

  Even though the model is non-monotonic, it may represent real data.  Some
  EDA tools will correctly process the model.  However, the recently
  implemented Waveform endpoint tests now report an Error instead of a
  Warning, preventing the model to be processed in systems that uses
ibischk3
  for input model parsing.

  Bob suggested classifying BUG57 as Annoying, Low, and Open.

  The problem is how to resolve BUG57.  The choices are (1) fix the test,
(2)
  change the Error back to a Warning, or (3) ignore this problem and force
the
  user to modify the IBIS file.

  Bob suggested that we work on (1) as a low priority activity.  If the fix
is
  too difficult, then we might consider (3).  No one wanted (2).  Stephen
  Peters suggested that a note could be added to the Warning or Error
message
  to alert the user of a possible reason for the Error Message so that the
  user could modify the model.  Bob suggested that because this is a low
  priority bug, it should be investigated after all the other open bugs are
  fixed.  Then we can decide how to proceed.

END OF MEETING TOPIC
Roy Leventhal stated that he talked about signal integrity and IBIS at a 
recent IPC Design Learning Symposium meeting.  He will track their activity.

NEXT MEETING:
The next teleconference meeting will be on Friday, August 10, 2001, from 
8:00 AM to 10:00 AM.  BIRD70.4 and BIRD71 are scheduled for a vote.
============================================================================
==
                                      NOTES

IBIS CHAIR: Stephen Peters (503) 264-4108, Fax: (503) 264-1831
            [email-masked]
            Senior Hardware Engineer, Intel Corporation
            M/S JF4-215
            2111 NE 25th Ave.
            Hillsboro, OR 97124-5961

VICE CHAIR: Bob Ross (503) 685-0732, Fax (503) 685-4897
            [email-masked]
            Modeling Engineer, Mentor Graphics
            8005 S.W. Boeckman Road, Wilsonville, OR 97070

SECRETARY:  Guy de Burgh (805) 988-8250, Fax: (805) 988-8259
            [email-masked]
            Senior Manager, Innoveda
            1369 Del Norte Rd.
            Camarillo, CA 93010-8437

LIBRARIAN:  Roy Leventhal (837) 797-2152, Fax: (847) 222-2799
            [email-masked]
            Senior Engineer, CommWorks Corp. (a wholly owned 3Com
subsidiary)
            1800 W. Central Rd.
            Mt. Prospect, IL 60056-2293

WEBMASTER:  Syed Huq (408) 525-3399, Fax: (408) 526-5504
            [email-masked]
            Manager, Hardware Engineering, Cisco Systems
            170 West Tasman Drive
            San Jose, CA 95134-1706

POSTMASTER: John Angulo (425) 869-2320, Fax: (425) 881-1008
            [email-masked]
            Development Engineer, Innoveda
            14715 N.E. 95th Street, Suite 200
            Redmond, WA 98052

This meeting was conducted in accordance with the EIA Legal Guides and EIA
Manual of Organization and Procedure.

The following e-mail addresses are used:

  [email-masked]
      To join, change, or drop from either the IBIS Open Forum Reflector
      ([email-masked]), the IBIS Users' Group Reflector ([email-masked])
      or both.  State your request.

  [email-masked]
      To obtain general information about IBIS, to ask specific questions
      for individual response, and to inquire about joining the EIA-IBIS
      Open Forum as a full Member.

  [email-masked]
      To send a message to the general IBIS Open Forum Reflector.  This
      is used mostly for IBIS Standardization business and future IBIS
      technical enhancements.  Job posting information is not permitted.

  [email-masked]
      To send a message to the IBIS Users' Group Reflector.  This is
      used mostly for IBIS clarification, current modeling issues, and
      general user concerns.  Job posting information is not permitted.

  [email-masked]
      To report ibischk2/3 parser bugs.  The Bug Report Form Resides on
      eda.org in /pub/ibis/bugs/ibischk/bugform.txt along with reported
bugs.

      To report s2ibis, s2ibis2 and s2iplt bugs, use the Bug Report Forms
      which reside under eda.org in /pub/ibis/bugs/s2ibis/bugs2i.txt,
      /pub/ibis/bugs/s2ibis2/bugs2i2.txt, &
/pub/ibis/bugs/s2iplt/bugsplt.txt
      respectively.

Information on IBIS technical contents, IBIS participants, and actual
IBIS models are available on the IBIS Home page found by selecting the
Electronic Information Group under:

  http://www.eigroup.org/ibis/ibis.htm

Check the pub/ibis directory on eda.org for more information on previous
discussions and results.  You can get on via FTP anonymous.
============================================================================
==

---

From: "LiuWeidong" <[email-masked]>
Date: Wed, 25 Jul 2001 09:13:30 +0800

For the message bellow, 
" Even though the model is non-monotonic, it may represent real data"
" (3) ignore this problem and force  the   user to modify the IBIS file."
" Bob suggested that we work on (1) as a low priority activity.  If the fix  is   too difficult, then we might consider (3).  No one wanted (2).  "

I want to ask:
It seems that a  good model maybe is non-monotonic(right or wrong ?),Then how can we modefy the IBIS file ?

Thanks,
regards,
LiuWeidong

----- Original Message ----- >

---

From: Lynne Green <[email-masked]>
Date: Wed, 25 Jul 2001 09:07:10 -0700

The EDA tools have to be able to use these models, which means the models
must pass the parser.

A smart user will send the model back to the person who made it, to verify
whether the non-monotonicity is "real", before proceeding with simulation.

- Lynne

At 09:13 AM 7/25/2001 +0800, LiuWeidong wrote:
>" Bob suggested that we work on (1) as a low priority activity.  If the 
>fix  is   too difficult, then we might consider (3).  No one wanted (2).  "
>
>I want to ask:

---

From: Bob Ross <[email-masked]>
Date: Wed, 25 Jul 2001 13:55:24 -0700

Hello LiuWeidong and Lynne:

Let me clarify that the problem in bug57 is
not the non-monotonic behavior itself.  The
issue is that the waveform endpoint test
incorrectly fails.  The waveform endpoints
are actually correct, the the non-monotonic
behavior described in bug57 causes the parser
itself to not find the correct endpoints.  This
causes the model to fail because we recently
changed the endpoint test (bug47) to issue
an Error when the mismatch is greater than 10%.

So a good model may be rejected because of
the ibischk3 bug.  The region where the
failure occurs however, is not critical
(e.g., in an extended clamping region where
no current could possibly flow anyway.  The
easy (3) fix is just to change the current in
that region to be monontonic.  This type of
change would be on a case-by-case basis
based on where the problem is.

I suspect that the parser problem is based
an algorithm that starts at one end of a
table to find a solution.  If the algorithm
started at the middle to find the solution,
this would be less of a problem.

See bug57 for a test case and more information:

  http://www.eda.org/pub/ibis/bugs/ibischk/bug57

Bob Ross
Mentor Graphics

---

From: Jason Leung <[email-masked]>
Date: Thu, 26 Jul 2001 08:51:47 -0400

Hi Bob:

I have been following the non-monotonic question and I have a question to ask
regarding to the end points,  how does the parser calculate the -5.42V ? I wanted to
know where is the -5.42V coming from?

thanks
Jason Leung

"Four Errors are produced.  An example is below

ERROR - Model out_bad: The [Falling Waveform]
      with [R_fixture]=50 Ohms and [V_fixture]=0V
      has TYP column DC endpoints of  0.00V and  2.50v, but
      an equivalent load applied to the model's I-V tables yields
      different voltages (-5.42V and  2.50V),
      a difference of -100.00% and  0.00%, respectively.

The calculated end point of -5.42 is wrong because of the non-monotonic
data.

When the non-monotonic points are commented out, 0 Errors are produced.

The testing routine should check matching voltages starting at the middle
of the I-V tables.  Some EDA tools will accept such a model.

The options are (1) fix the text, (2) reduce Error to Warning - so tools
that accept it will work, or (3) accept this as a failure - and reject the
model if the ibischk3 parser is used for the parsing."

---

From: Bob Ross <[email-masked]>
Date: Thu, 26 Jul 2001 12:46:37 -0700

Jason:

For the non-monotonic example, -5.42 (actually 5.4167)
is one solution for which the current from the
extrapolated [Pulldown] table sinks the same current
out of the 50 ohm load.  However, if the algorithm
started with voltages in the normal operating
range or midrange in the pulldown table, the
solution 0.00 would have been found that matches
the waveform end point.

Bob Ross
Mentor Graphics