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IBIS INTERCONNECT MODELING AD HOC TASK GROUP MEETING MINUTES AND AGENDA

http://www.eda.org/ibis/adhoc/interconnect/

Mailing list: ibis-interconn@freelists.org

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Next Meeting
Wednesday, March 26, 2008
9 AM US Pacific Time

               Telephone     Bridge   Passcode
              916-356-2663     4      710-7827

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Agenda:
- Call for patents
- Opens
- Review of Touchstone(R) 2.0 advanced mixed-mode example (Ken Wong)
- Mixed-mode support discussion

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Minutes from March 19:

Attendees:
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(* denotes present)
Agilent                    - Radek Biernacki*, John Moore, Ken Wong*
Ansoft                     - Denis Soldo*
Green Streak Programs      - Lynne Green
Hewlett-Packard            - Rob Elliott*
Intel                      - Michael Mirmak*
Mentor Graphics Corp.      - John Angulo*
Micron Technology          - Randy Wolff*
Sigrity                    - Sam Chitwood*, Raymond Y. Chen
SiSoft                     - Walter Katz*
Teraspeed Consulting Group - Bob Ross*

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No opens were raised.  No patents were announced.

Ken Wong reviewed the mixed-mode example he provided, showing a four
port single-ended system represented captured as two mixed-mode ports.
Port ordering, port impedance and other key information is provided 
through comments.  A port assignment table leads the file, showing
which single-ended matrix rows and columns in Touchstone contain the
SDD, SCD, etc. mixed-mode information.  Port impedances are still
given in single-ended terms.  Ken noted that the format is primarily one
of convenience.  He further suggested that the data might be represented
twice -- once as single-ended and once as mixed-mode -- if file formatting
becomes problematic.

Bob Ross suggested that a general-purpose language might have to be
defined to cover both the single-ended and mixed-mode variations.  This 
could take some time.  Ken noted that he would prefer closure sooner
rather than later.  Walter Katz added that, to save time, port ordering
might be best treated in 2.0, with mixed-mode in 3.0.

Michael Mirmak inquired about the port assignments in the Agilent Balanced
Network Parameters application note (link below).  The arrangement of 
mixed-mode data into quadrants in the paper does not match the assumptions
in the example.  

Sam Chitwood commented that repeating data or a simplified/assumed assignment format
might work for a minimal number of ports, but a package with numerous ports
(100+) could result in an unwieldy Touchstone file.  

Radeck Biernacki added that some sort of port labeling might
be required to identify port numbers greater than 10 unambiguously (e.g., is
S115 = S 11<->5 or 1<->15?).  Bob Ross raised some additional concerns that
the impedance assignments might be incomplete or require an override
assumption depending on interactions with the original # token and common-mode
and differential port terminations. 

The team will continue the discussion at the next meeting.

Agilent paper link: http://www.home.agilent.com/upload/cmc_upload/All/EPSG084733.pdf


ARs
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Ken Wong - provide attendees with another example of mixed-mode output,
           featuring more than 2 mixed-mode/4 single-ended ports - DONE

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Team Objectives:
1) complete ICM-IBIS linking BIRD and any associated changes to the 
   ICM specification
2) update the ICM specification, if needed, to clarify the mapping of 
   ICM nodes to S-parameter ports
3) complete a specification for "Touchstone Plus" or similar 
   industry-standard definition for Touchstone-like files, to include 
   complex impedance references, removal of limits on the maximum number
   of ports and per-port impedance references