Subject: November 5, 1993

From: Cathy Lundberg <[email-masked]>
Date: Mon, 8 Nov 93 17:53:09 PST

November 5, 1993
From:           Cathy Lundberg     (503) 696-4620,  fax (503) 696-4904
                Will Hobbs    (503) 696-4369, fax (503) 696-4210
Subject:        Minutes from IBIS Open Forum 10/29/93
To:

Anacad                  Petra Osterman
AnSoft                  Henri Maramis
Cadence Design          Sandeep Khanna, Chris Reed, Pawel Chadzynski, Kumar*
Contec                  Maah Sango*, Clark Cochran
High Design Technology  Michael Smith
HyperLynx               Steve Kaufer, Kellee Crisafulli
Integrity Engineering   Greg Doyle, Wayne Olhoft
Intel Corporation       Stephen Peters*, Gary Saunders, Jim Alexander, Don 
Telian,
                        Arpad Muranyi*, Donna Rendon, Will Hobbs*,
                        Cathy Lundberg*
Interconnectix, Inc.    Bob Ross*
Intergraph              Ian Dodd
IntuSoft                Charles Hymowitz
Logic Modeling Corp.    Randy Harr*
Mentor Graphics         Greg Seltzer, Ravender Goyal
Meta-Software           Stephen Fenstermaker
MicroSim                Arthur Wong*, Meeling Wei, Jerry Brown, Graham Bell
North Carolina State University Paul Franzon
PC Ware                 Paul Munsey
Performance Signal Integrity    Vivek Raghawan, Eric Bracken*
Quad-Design             Jon Powell*
Quantic Labs            Mike Ventham*, Zhen Mu
Siemens Nixdorf         Werner Rissiek*
Texas Instruments       Bob Ward*
Thomson-CSF/SCTF        Jean Lebrun
Zeelan Technology       Hiro Moriyasu, George Opsahl*, Samie Samaan, Tay Wu

Cc:  Intel Corporation  Randy Wilhelm, Jerry Budelman, Intel IBIS team

In the list above, attendees at the 10/29 meeting are indicated by *

Future meetings:  Face to face IBIS Summit, Santa Clara, CA:  Nov. 12, 1993,    
                  8:00-5:00 PST
                  Phone number:  (916)356-9999.  Reservation Number:  130639

Please note:  If you know of someone new who wants to join the email reflector 
([email-masked]), or have updates to your email address, email to 
[email-masked].

10/29 Meeting Agenda:

9:00    Check-in
9:05    Introductions of new IBIS members
9:10    10/1 Minutes Review, Opens for New Issues       Will Hobbs
9:15    Press Release, Trademark issue                  Randy Harr, Will Hobbs
9:25    Summit Planning
                Attendees
                Presenters
                Discussion Chairs, Topics
9:40    SCVs                                            Will Hobbs, All
9:45    BBS Updates                                     Siuki Chan, Randy Harr
9:50    BIRDS
                ECL, BIRD #1                            Stephen Peters
                VIH, VIL Input Threshold, Bird #2       Jon Powell
10:20   10/1 Opens
                #6 Open Side (shelved)                  Kellee Crisafulli
                #7 .pkg                                 Eric Bracken
                #8 Thresholds for Timing                Jon Powell
                #9 Monotonicity                         Kellee Crisafulli, Arpad
                                                        Muranyi
10:50   Wrap-Up
        Action Items
        Next Meeting Plans

Minutes
I.  Open Issues:

Atmel called, they will be doing IBIS models.
Motorola will do IBIS models of the PowerPC.  They may attend the summit.

No corrections to minutes.

Paul Munsey has not been paid by one company.  The group agreed that a check 
should be issued to Paul by Will from the IBIS account.

AR:  Will - issue check to Paul Munsey from the IBIS account. Update: waiting on
final confirmation of facts.

Changes to coding style would make 2.0 easier to use, and easier to write 
translators.  Jon would like people to talk to Paul about it.

We'll send out directions to get to the summit to reflector by next Monday.  A 
map will also be sent with the faxed minutes.

AR:  Cathy - send directions to get to the summit to the reflector.  DONE
AR:  Cathy - fax map to Bob Ward.  DONE

II.  Press Release:

Texas Instruments didn't get deleted from the copy and TI did appear in a couple
of places as supporting the IBIS standard.  The final release went out without 
Randy's review.  Key editors were called about the mistake and corrected copies 
were faxed to several places.  No backlash is expected at TI. 

We have a letter on letterhead from every company but Intel authorizing the 
press release.

The IBIS Overview document that will be sent out on request by Karen Kirkpatrick
at Cadence has not been sent to her yet;  It has been reviewed by various Intel 
people and Jon Powell and still needs some revision.  It is a nice overview, but
gets too specific in some areas.  For example, some simulator vendors have 
varying support for the ability to accurately model traces, so the document 
should give transmission line values instead of trace lengths, etc.  Subsequent 
to the meeting, we learned that Cadence has received a few requests yet as far 
as we know.  Robin (Intel's tech writer working on the document) is making final
revisions.  She will finish shortly and we will submit it to vhdl.org and fax it
to our standard fax list.

The press release got low coverage because of the HyperLynx press release that 
went out earlier.  Also, the press release was just on white paper, not on slick
letterhead with a packet.  The next time we issue a press release we should have
each company generate their own press release which we can then assemble 
together to send out.  We need to make sure we time it right and release the 
information at the same time.

We have some potential logos to use for IBIS.  The results of the trademark 
search are in a 50 page document that Logic Modeling has - any paying IBIS 
member can get it from them.

III.  Summit planning:

A session led by Kumar of Cadence and Eric Bracken (now Vivek Reghawan) of 
Performance Signal Integrity will discuss modeling simultaneous switching / 
ground bounce, which drivers talk to which pins, different supplies powering 
different pins, representing Vcc pins shared by buffers, timing and noise 
implications and dual supply components. 

AR:  Kumar - let Will or Cathy know your topic of discussion by 11/5.

Other potential sessions:

Data measurement and derivation methods - how semiconductor vendors derive data.
 Other semiconductor vendors have rise times characterized differently than 
Intel does.  It would be nice to have Intel, Motorola and Texas Instruments talk
about this.

In order for IBIS to be useful, semiconductor vendors need to get involved.  
Will is inviting some companies to the summit.  Others should do the same.

We would like to see foils ahead of time so we can have copies prepared.  We 
will also send out copies afterward as necessary.

November 12 IBIS conference agenda
8:00 - 5:00  SC4-150

Note: Intel will provide coffee and lunch.

8:00    All                                     Assemble, get aquainted, have   
                                                coffee
8:20    Will Hobbs      Intel                   IC vendor view of IBIS
8:45    Randy Harr      LMC                     Die 0.9 bare die spec work with 
                                                National
9:15    Bob Ross        Interconnectix          Measurement and Extraction of   
                                                buffer data
9:45    Break
10:05   Jon Powell      Quad-Design             Slew Controlled Devices
10:25   Arpad Muranyi   Intel                   V/I/T
10:40   Panel                                   Handling Dynamic                
                                                Characterization of Buffers
12:00   Lunch
1:00    Kumar           Cadence                 Implementation of IBIS models   
                                                using current controlled voltage
                                                sources
1:20    Vivek Raghawan  Performance             Package Parameters
                        Signal Integrity
1:40    Panel                                   Package Parameters
2:10    Panel                                   SSO:  Sharing of Vcc and Ground
2:45    Break
3:05    BIRD discussion, voting
4:00    Open issues, action item review, summary

BIRDs

BIRD #1
We discussed ICs in which diodes and buffer transistors are referenced to 
different voltage rails.  Stephen Peters proposed that he add support for 
multiple voltage rails to BIRD#1.  Because of the other issues that came up with
diodes on ECL parts and requirements for mixed supply parts, he decided to 
rewrite the BIRD#1 to include voltage rail statements, put it out as BIRD#3, to 
substitute for BIRD#1, and close BIRD#1.  Since the meeting, Stephen concluded 
that it was easier to revise and close BIRD#1, replaced by BIRD#3, dealing with 
ECL alone.  He has also created BIRD#4 to address multiple rails.

On the subject that Bob Ross brought up during the previous meeting regarding 
diodes on ECL parts, the clamp diodes on ECL parts are strictly for ESD 
protection and don't affect the signals in normal operating conditions.  The 
signal swings in ECL are so small that the ESD diode should never be forward 
biased.  If the diodes are turned on, the part is far beyond operating ranges.  
With the new voltage rail support in BIRD#4, the user would be able to specify 
the ESD diodes.

Kumar discussed Cadence's approach to multiple rails.  In their table called VI,
they use a keyword, "vreference" that specifies the Vcc used for that curve.  
Kumar says that this approach is very simple and works.

AR:  Kumar write up example and send to reflector. - Done.

BIRD#2

Bird 2 - there are many unresolved issues regarding input thresholds.  There was
a discussion on what the real trip point should be for logic devices and how we 
might handle non-logic devices such as resistor packs.

AR- Jon Powell  post BIRD#2 to reflector Friday afternoon.  DONE

We engaged in a discussion on monotonic behavior.  There are two aspects to be 
dealt with.  1) How should we deal with output buffers that exhibit 
non-monotonic behavior (and in what situations does this occur), and 2) Must 
data be entered in the IBIS file monotonically?

1) Non-monotonic buffer behavior:  Arpad asked, "Do we require monotonic 
behavior in curves?"  If this is a requirement, the parser must check for 
monotonicity.

Jon Powell said that customers want to model non-monotonic parts.  Non-monotonic
behavior can result from slow feedback designed to prevent parts from melting;  
thus is is more of a DC phenomenon than an AC phenomenon.  Does this pose a 
convergence problem for some simulators?  Is a DC representation of the curve 
acceptable for some devices?  Due to DC current limiting, DC measurements may 
imply non-monotonic behavior that would never actually occur under real 
switching conditions.  How do we measure in an AC manner instead of DC manner?

Behavior that is nonmonotonic due to feedback goes into the controlled slew rate
discussion, modeling the dynamic characteristics of device.  For IBIS to be 
useful, it must deal with negative resistance regions.

2)  Monotonic data entry:  We felt that in IBIS tables, voltage values should be
monotonically rising or falling, but that current values may change.   The 
parser should check whether the data is good, but it shouldn't restrict the type
of data.  A BIRD against the parser should be written at some point to add 
checks for this in rev 2.0.  No specific AR owner was identified.