04/16/02 Minutes of IBIS Quality Committee Conference Call

IBIS Quality Committee Members: 


Adam Tambone Adam.Tambone@fairchildsemi.com 
*Barry Katz bkatz@sisoft.com 
*Benjamin P Silva benjamin.p.silva@intel.com
Bob Ross bob_ross@mentor.org
*Eckhard Lenski Eckhard.Lenski@icn.siemens.de
Eric Brock ebrock@sisoft.com
Gregory R Edlund gedlund@us.ibm.com
Hazem Hegazy hazem_hegazy@mentorg.com
*John Figueroa jfigueroa@apple.com
*Kevin Fisher kfisher@sisoft.com
*Kim Helliwell kimgh@apple.com
Lynne Green lgreen@cadence.com
*Mike Labonte mlabonte@hhnetwrk.com 
Peter LaFlamme plaflamm@amcc.com
*Robert Haller rhaller@cereva.com
*Roy Leventhal Roy_Leventhal@3com.com
Sherif Hammad sherif_hammad@mentorg.com
*Todd Westerhoff twester@hhnetwk.com 
Tom Dagostino tom_dagostino@mentorg.com 

Everyone in attendance marked by  *


John Figueroa volunteered to explore the recording option on the
teleconference. This could be beneficial if someone was unable to
attend or wanted to review the conversation.  He is going to report
back on the options.

Continued working through checklist...

MODEL TYPE

Each buffer type has minimum, maximum, un-related data.  Un-related
data leads to confusion and improper tool operation.  Proposed was
that we define the minimum and the maximum per I/O type and give
example of un-related data (ie. output cells with Vih and Vil). There
will be issues here due to the fact that each of us has a
minumum/maximum.  This is a level of detail we will get into later

TEMPERATURE RANGE

For informational purposes.  25C is rarely typical. 40C is more
reasonable. Discussed need for multiple typical temperatures but
beyond scope.  Need to make sure range is correct/complete.  Vendor
needs to make reasonable guess at what typical operation conditions
are.  Use models for typical models are often to either get
correlation in the lab or to determine operational marigins under
typical conditions when broken at PVT extremes.

CORNER MODELS

Corner models should be included. There are exceptions (ie measured
data). IV and VT curves should be generated under identical conditions
(else VT/IV mismatch).  Data sheets should bound IV curves.

VOLTAGE RANGE

Unfortunate that IBIS makes curves VCC relative -- can't crosscheck
Voltage to IV.  Can't change without re-gen of IV/VT curves.

MIN/TYP/MAX

Across all parameters these need to be complete/correct.

C_comp

What is the source? (simulation, measurement,
guessed). Driver/receiver C_comp values can be different. Often have
to make engineering judgement as to what is the proper value. As an
example, in one application it may be perfectly acceptable to average
driver/receiver C-Comp values (ie. 4pF vs 3pF -- use 3.5pF) but in
others it may. Document what was done and show due diligence.


STANDARD LOAD

VREF, CREF, RREF, Vmeas should be in model for output cells. Should
match data sheet (traceability to version) Some standard loads not
supported in IBIS.  If this is the case, should document in model.
Should document in IBIS model if IBIS insufficiencies.

IV CURVES 

Must look at actual IV curves.  Visual inspection for Typ/Min/Max
correctness.  In some cases, results will be non-intuitvie (ie SS model
stronger than FF due to process overcompensation).  Note if
non-intuitive.  Some discussion as to whether a model should ever have
MAX curves weaker than MIN curves -- food for thought.

IBISCHK

It was agreed that one of the outputs of our efforts would be to
document problems with IBISCHK that prevent High-Quality IBIS models
from passing.  Roy was going to bring up making the IBIS golden parser
open source at the next meeting.


