======================================================================

IBIS INTERCONNECT TASK GROUP
http://www.ibis.org/interconnect_wip/ 
Mailing list: ibis-interconnect@freelists.org 
Archives at http://www.freelists.org/archive/ibis-interconn/ 

======================================================================

Attendees from July 26 Meeting (* means attended at least using audio)

ANSYS                                Curtis Clark
Cadence Design Systems               Bradley Brim
Cisco                                David Siadat
Intel Corp.                          Michael Mirmak
Keysight Technologies                Radek Biernacki, Ming Yan
Mentor, A Siemens Company            Arpad Muranyi*
Micron Technology                    Justin Butterfield*, Randy Wolff*
SAE ITC                              Maureen Lemankiewicz, Logen Johnson
Signal Integrity Software            Walter Katz*, Mike LaBonte*
Teraspeed Labs                       Bob Ross*
University of Aveiro in Portugal     Wael Dghais


Mike LaBonte convened the meeting.  No patents were declared. 
Justin Butterfield took minutes.


Review of Minutes:
- Mike called for review of the minutes from the July 19 meeting.
  Randy Wolff moved to approve the minutes.  Arpad Muranyi seconded. 
  The minutes were approved without objection.


Review of ARs:
- Mike to update the BIRD189.5 draft 3 and send it out to mailing list.
  - Mike reported this is done.

Opens: 
- None


BIRD189.5 draft 4:
Randy had sent out an email about the 60 character limit for the [Description]
field.  He mentioned the character limit of 60 is to restrictive to accurately
describe the [Interconnect Model Set].  He suggested a character limit of 120 or
more.  Walter Katz suggested the limit should be 256.  Bob Ross commented that
the AMI Description has a limit of 120.  Bob mentioned there could be
readability issues if we make it too long.  He also noted that carriage returns
are not permitted.  Arpad suggested to use the 1024 character line limit in
IBIS.  Mike suggested to simply delete the character limit rule text which
would make the limit be set by the IBIS 1024 line limit.

Bob suggested to also change the character limit for the [Define Package Model],
[Description] keyword.

Randy mentioned there is no example for Number_of_terminals and thought an
example in the rules section would be useful.  Mike added Randy's suggested
example to the draft.

Mike asked about the other sections.  Randy stated terminal line rules is
more complex and needs to be described completely.   Bob mentioned the
Unused_port_termination rules does not have an example.  Mike pointed out
that we do have several examples with terminal lines, but it might not be clear
that these are terminal lines.

Arpad suggested to add an example for Unused_port_termination.  Mike added one
to the draft.

Randy noted that on page 18, the [Interconnect Model], Other Notes section is
saying that you can have power only or signal only model.  Arpad stated that the
word terminal is changing the meaning of these sentences.  He suggested to
delete the word terminals from these sentences.  Arpad suggested to refer to 
these as power rail models and I/O signal models.  Randy suggested to change the
list of sentences to a bullet list.

Mike changed Example 6 per Arpad's email to swap the terminal line between the
two [Interconnect Model]s.

Walter mentioned that he had sent out an email about what should be done with
unused terminals in the case of measurements.  The consensus from industry
experts is that, ideally, unused ports should be terminated with the reference
impedance, despite this being difficult to achieve in most physical measurement
cases.   

Walter stated the following: "In there is no interconnect on an NC pin, then
that interconnect should not be included in the subckt or Touchstone File.

POWER and GND terminals should not be unused.

POWER and GND pins should be supplied with an actual voltage.

When a terminal is unused it is meant to be ignored, so it should be terminated
with:
Touchstone files should be terminated with the Port Reference 
(or the Unused_port_termination)
IBIS-ISS models should be terminated with ~50 Ohm (or the 
Unused_port_termination)."

Arpad asked about POWER and GND terminals and if these terminals are not used in
a particular simulation, how the EDA tool should handle those cases.  Walter
stated that when a terminal is unused it is meant to be ignored, so it should be
terminated.  

Bob commented that Walter's unused terminal rules are debatable.  Walter stated
there are some special cases to consider.  Bob asked, for simulation, what the
best termination is.  He mentioned that when you have a model with a large
number of ports, there needs to be a way to simplify it if the user only wants
to simulate a few ports.

Walter commented that he has an issue with the third paragraph in the
Unused_port_termination rules.

Arpad stated there was a recommendation in the ATM meeting to delete the
Unused_port_termination parameter all together.

Mike will post the 189.5 draft 4.


Walter moved to adjourn.  Arpad seconded.  The meeting adjourned without
objection.