[ibis-macro] Minutes from the 11 Sep 2012 ibis-atm meeting
- From: Mike LaBonte <mike@xxxxxxxxxxx>
- To: IBIS-ATM <ibis-macro@xxxxxxxxxxxxx>
- Date: Tue, 18 Sep 2012 10:04:14 -0400
Minutes from the 11 Sep 2012 ibis-atm meeting are attached.
Mike
IBIS Macromodel Task Group
Meeting date: 11 Sep 2012
Members (asterisk for those attending):
Agilent: * Fangyi Rao
* Radek Biernacki
Altera: * David Banas
Julia Liu
Hazlina Ramly
Andrew Joy Consulting: Andy Joy
ANSYS: Samuel Mertens
* Dan Dvorscak
* Curtis Clark
Steve Pytel
Luis Armenta
Arrow Electronics: Ian Dodd
Cadence Design Systems: Terry Jernberg
* Ambrish Varma
Feras Al-Hawari
Cavium Networks: Johann Nittmann
Celsionix: Kellee Crisafulli
Cisco Systems: Ashwin Vasudevan
Syed Huq
Ericsson: Anders Ekholm
IBM: Greg Edlund
Intel: * Michael Mirmak
Maxim Integrated Products: Mahbubul Bari
Mentor Graphics: * John Angulo
Zhen Mu
* Arpad Muranyi
Vladimir Dmitriev-Zdorov
Micron Technology: Randy Wolff
* Justin Butterfield
NetLogic Microsystems: Ryan Couts
Nokia-Siemens Networks: Eckhard Lenski
QLogic Corp. * James Zhou
Sigrity: * Brad Brim
Kumar Keshavan
Ken Willis
SiSoft: * Walter Katz
Todd Westerhoff
Doug Burns
* Mike LaBonte
Snowbush IP: Marcus Van Ierssel
ST Micro: Syed Sadeghi
Teraspeed Consulting Group: Scott McMorrow
* Bob Ross
TI: Casey Morrison
Alfred Chong
Vitesse Semiconductor: Eric Sweetman
Xilinx: Mustansir Fanaswalla
Ray Anderson
Note: The name "Abhishek Munjal" appeared in NetMeeting but no corresponding
voice was heard.
The meeting was led by Arpad Muranyi
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Opens:
- None
--------------------------
Call for patent disclosure:
- None
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Review of ARs:
- Michael M provide examples to show what IC vendors need
- Done with part 1
- Need questions answered to do part 2
-------------
New Discussion:
Michael M showed "Package Model Format Needs":
- Michael M: This is part 1
- slide 3:
- Michael M: We address two types of analysis and three user segments
- We try not to put a large burden on any single segment
- slide 4:
- Michael M: For post-layout user may have specific nets to look at
- They may not have been identified by name
- May want to look at signals with crosstalk over some threshold
- Besides format, there is a question if the same data is useful pre and
post layout
- slide 5:
- Michael M: Three ways to look at the problem:
- Full model
- Small swath model
- Many small models
- Need to look at how each user sees each type
- Swathed models will be hard for EDA vendors to develop
- slide 6:
- Michael M: The model maker controls the destiny of the other two
- The ideal case is where the end user controls what is extracted
- That will be hard to do
- Arpad: Why is that difficult?
- Michael M: The person controlling distribution limits what it will cover
- Small models are more work to create, easy to use
- Large models are easy to make, hard to use
- back to slide 5:
- Walter: On large models the through paths must be accurate
- There are limited coupling paths that must be examined
- Sparse formats will reduce file size
- The EDA tool can choose what to use
- S20p models can be quickly extracted from s1000p models
- Michael M: That is entirely in the context of s-parameters
- Am I automatically limited?
- Walter: ???
- Michael M: Then the extraction tool should be able to use coupling info for
that
- James: For most buses the highest pin count is about a thousand
- Probably need 1 to 5 aggressors max
- The standard should allow arbitrarily large models
- Tools should be able to make it easy for end users
- Michael M: We don't want the standard to eliminate possibilities, agree
- But some customers create "unusual" designs where crosstalk is more of a
problem
- Time domain models other than s-parameters are an issue too
- Walter: Some simulators have trouble with long chains of short s4ps
- Package models should not have many of those
- Michael M: For part 2 a swathed s12p example might be good
- Walter: Some vendors deliver s4ps and expect them to be combined
- This might be an alternative to swathing
- Brad: It's easy to violate passivity with those
- James: It is easy to measure return losses and combine into an s16p
- Radek: When we neglect far coupling we sacrifice accuracy
- This has to be well understood
- Usually we only have full matrices
- Michael M: Has anyone tried creating an sZILLIONp model from lab data?
- Equipment requires tricks to do that
- Walter: It has been done up to 150
- James: We have seen around 130
- Arpad: Have we seen this done?
- Michael M: I have not seen a case where sparse data is used for full
simulation
- Arpad: Walter may have an example
- Walter: I emailed one, but it only has about 20 pins
- Scott has also proposed creating s1000p models
- Michael M: We should err on the side of giving as much data as possible
- Reducing data for specific applications may not help
- Walter: My format has no inherent size limitation
- Model makers will be aware of tool limitations
- Arpad: BIRD 125 can be modified to meet these needs
- We need to answer some questions before proceeding
- Michael M: The hybrid solution may be best
- The existing spec has interactions that are hard to understanding
- A simpler IBIS spec that connects pins/pads to other things would help
- A pad keyword would be better
- Walter: I would like to show the email I sent
- Arpad: Maybe we should reorder our priorities first to get other BIRDs out of
the way
- We need to address the AMI analog model problem
- Could packaging be handled by a subcommittee
- Michael M: The interconnect task group could come back
- Arpad and Walter liked the idea
AR: Michael M restart interconnect task group meetings Wednesdays 8am or 9am PT
Walter showed an example IBIS file and example package tree syntax:
- Walter described the tree syntax
- Walter: Corners might be limited to three, although more might be needed by
some
- This might be called a mixed model
- Walter showed a full package model example tree syntax
- In this one each pin is a victim
- It shows the power and ground pins
- This is a simple, incremental change to IBIS
- A separate file might also describe the on-die models
- James: Are these competing against each other?
- Walter: One might use one where there is crosstalk and another elsewhere
- In pre-layout there may not be pin names
- They are three views of the interconnect
- James: The semantics are different
- Walter: Yes
Arpad: Would interconnect meetings start tomorrow?
- Walter: I think we have to assume next week
- James: We have to consider the model maker burden of these syntaxes
- For the user it may be hard to choose which model to use
- End users should choose how many aggressors, etc.
- Walter: A full model would be the only source data needed
- This single syntax allows any use we want
- Brad Brim might want to add XY coordinates
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Next meeting: 18 Sep 2012 12:00pm PT
Next agenda:
1) Task list item discussions
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IBIS Interconnect SPICE Wish List:
1) Simulator directives
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