Minutes for IBIS Quality Committee meeting.
May 14, 2002 11:00am EST


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  *


Minutes:
-Roll call


-Review of Action Items

Siemens is still working on spec. Should be ready by next meeting.

Kim Helliwell is working on proposal for open source of golden
parser. A draft will be sent out this week for review.

Roy to send out pointer to Accuracy documents.


-Discussion of Greg Edlund's email about a figure of merit.

  Greg provided clarification.  Figure of merit would apply to
  accuracy section of checklist -- not to the IBIS model as a whole.
  Warrants further discussion when we get to the HSPICE correlation
  section of the checklist.

-Review of VT/Ramp section of checklist.

  Current list of items in the checklist reviewed.  

  Ramp checks include:

  Are dV 20%-80%? (IBIS committee specified that dT is the only value
  of interest. dV included as informational/verification only.)

  Check for min/typ/max swizzle.

  No negative values for Ramp.

  No Zero values for dV or dT.

  VT curves do not have to be generated under same load conditions as
  Ramp data however, when they are they should be consistent and
  crosschecked. Eckhard noted when VT curves have been created
  in-correctly, and the Ramp data was derived from the VT curves, then
  both the VT curves and ramp data are useless.

  Discussion on whether we should recommend a termination for people
  to use when generating VT curves led to discussion on portability
  vs. accuracy.  Lots of issues here. A general consensus is that
  high-quality models will be portable across multiple simulators --
  even at the expense of some accuracy.   

  For portability across simulators 50ohm to VCC/GND RISING/Falling
  waveforms in general seems to be the best.  However, exceptions were
  pointed out (ie differential LVDS ). 

  Miscompares between IV and VT curves should be documented as to why.
  Currently the IBIS Golden parser generates a warning between 2% and
  10% miscompare, and error at >10%. V4.0 of IBIS will allow up to
  1000 V-T points potentially reducing the amount of
  discrepancies. (Currently constrained to 50 points.)

  Visual inspection of VT curves:. 
  
     Are DC states achieved?
  
     Is curve Monotonic?  This is expected, so if it's not, then it
     should be noted. Note: Improper Fixture values can produce
     non-monotonic waveforms. This may be OK for documentation
     purposes (ie lab measurements), but not for driving a simulator.

     For portability, leading/trailing delays from curves should be
     removed. This may be at the expense of accuracy in some
     simulators, but with the benefit of providing consistency across
     all simulators related to potential frequency limitations of a
     model.

	 Is removal of the delays consistent across rising and falling
     waveforms. This a complicated issues that will require further
     discussion and may alter or conflict with preceding
     paragraph. (Can also cause simulator dependencies.)

	 Want to avoid multiple sets of VT curves.

-All errors/warnings need to be explained in checklist.
     
     Bob pointed out that some warnings are put in place to flag
     certain values that may or may not be of concern to any
     particular user.  These explanations would go in the notes
     section associated with warnings and errors in the checklist.



-Next meeting will be in two weeks, May 28, 2002. 11:00am EST.

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