IBIS Macromodel Task Group

Meeting date: 10 February 2009

Members (asterisk for those attending):
  Ambrish Varma, Cadence Design Systems
* Anders Ekholm, Ericsson
* Arpad Muranyi, Mentor Graphics Corp.
  Barry Katz, SiSoft
* Bob Ross, Teraspeed Consulting Group
  Brad Brim, Sigrity
  Brad Griffin, Cadence Design Systems
  David Banas, Xilinx
  Donald Telian, consultant
  Doug White, Cisco Systems
* Eckhard Lenski, Nokia-Siemens Networks
  Essaid Bensoudane, ST Microelectronics
  Fangyi Rao, Agilent
  Ganesh Narayanaswamy, ST Micro
  Gang Kang, Sigrity
  Hemant Shah, Cadence Design Systems
* Ian Dodd, Agilent
  Joe Abler, IBM
* John Angulo, Mentor Graphics
  John Shields, Mentor Graphics
  Ken Willis, Cadence Design Systems
  Kumar
  Lance Wang, Cadence Design Systems
  Luis Boluna, Cisco Systems
  Michael Mirmak, Intel Corp.
* Mike LaBonte, Cisco Systems
  Mike Steinberger, SiSoft
  Mustansir Fanaswalla, Xilinx
  Patrick O'Halloran, Tiburon Design Automation
  Paul Fernando, NCSU
* Pavani Jella, TI
* Radek Biernacki, Agilent (EESof)
* Randy Wolff, Micron Technology
  Ray Comeau, Cadence Design Systems
  Richard Mellitz, Intel
  Richard Ward, Texas Instruments
  Sam Chitwood, Sigrity
  Sanjeev Gupta, Agilent
  Shangli Wu, Cadence Design Systems
  Sid Singh, Extreme Networks
  Stephen Scearce, Cisco Systems
  Steve Pytel, Ansoft
  Syed Huq, Cisco Systems
  Syed Sadeghi, ST Micro
* Terry Jernberg, Cadence Design Systems
  Todd Westerhoff, SiSoft
  Vikas Gupta, Xilinx
  Vuk Borich, Agilent
* Walter Katz, SiSoft
  Zhen Mu, Cadence Design Systems

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Opens:

Walter reviewed the recent IBIS summit meeting:
- There were two papers on EMI
  - There is definitely a need to characterize the EMI radiation of an IBIS
    component.
  - But there is no clear definition of what exactly is need to characterize
    the EMI radiation.
- Mixed mode papers by Vladimir Dimitriev-Zdorov and Yuriy Shlepnev
  - One on the mathematics, and one on some measurement data.
  - It gets interesting around 10GHz
  - Nothing relates to modeling issues we may have
- One paper compared simulations based on EBD vs Board Layout extraction.
- There were two IBIS quality papers:
  - High correlation between perception and actual
  - Failures can be as simple as getting [File name] wrong.
  - The Xilinx paper was about how to improve quality
- Two papers on Broadband IBIS analog model:
  - One on various methods of capacitor compensation when used with IBIS
    "Driver Schedule" buffers
  - Another on using Touchstone between the AMI model and the channel interconnect.


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Call for patent disclosure:

- No one declared a patent.

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Review of ARs:

- Arpad:  Write parameter passing syntax proposal (BIRD draft)
          for *-AMS models in IBIS that is consistent with the
          parameter passing syntax of the AMI models
          - TBD

- TBD:    Propose a parameter passing syntax for the SPICE
          - [External ...] also?
          - TBD

- Arpad:  Review the documentation (annotation) in the macro libraries.
          - Deferred until a demand arises or we have nothing else to do

-------------
New Discussion:

Walter discussed Todd's IBIS summit presentation "Broadband Analog Models":
- Page 3:
  - Handling of impulse response not fully specified
  - Ian: Is there any documentation of need?
  - IBM co-authored the paper:
    - Would like to enhance IBIS to handle freq-dependent C
    - Ian: It was shown that correlation was good without this
- Page 6:
  - Cadence and Sisoft get the same answers as HSSCDR
- Page 7:
  - The S-param model shown includes the buffer
  - It is stored in s4p files
  - Radek: So then non-linear effects are neglected
    - Walter: This is an AMI assumption
  - Arpad: S-param data often does not go to DC, needed for time domain
    - Walter: IBIS AMI is primarily freq dependent
  - Arpad: Does touchstone include DC?
    - It can, but doesn't have to
    - It is difficult to measure
    - Walter: Good transistor models help
    - Bob: Some tools can produce Touchstone from time domain simulation
- Page 9:
  - There are different proposals for freq dependent C
- Page 10:
  - Touchstone 2 does not have port map data, need to have this in the call
- Page 12:
  - S-param buffer model is an alternative if IBIS does not implement C(f)

Bob: How is the s-param generated?
- Ian: A paper to demonstrate the need would help
- Walter: Adge could answer this
  - Maybe he could join one of our meetings
- Ian: Can other vendors speak about guaranteeing these models?
  - Randy: Micron does not deal with serdes, so no opinion

Arpad: How does this relate to our interconnect language effort?
- Walter: IBIS Interconnect SPICE could replace the need for a direct Touchstone call
- Arpad: We should avoid duplication of effort
  - Walter: Would prefer to use Final_Stage subckt
  - John: This could be in an IBIS 4.1 circuit call
    - Walter: That only supports Berkeley SPICE
    - John: But tools tend to go beyond that
- Ian: We are jumping ahead, and should invite IC companies
- Bob: This proposal is an alternative to Final_Stage subckt
  - This should be good for ISI, eye diagrams, etc.
  - Arpad: This makes a good companion to IBIS

Arpad: We should be more organized in going forward:
- Ian: Can we have a meeting with IC vendors?
- Bob: Is anyone experienced in getting s4p buffer models?
- There was some discussion of vendor people who might participate
- Arpad: Should it be next week?
  - Walter: We will have to ask some people to see who can make it
  - Ian: Maybe this discussion should be in 2 weeks

AR: Walter invite IC vendors to meeting in 2 weeks using ibis-list

Walter: Next week we should go through proposed elements in detail:
- People should read the document in advance
- There was some debate about voltage sources

Next meeting: 17 February 2009 12:00pm PT

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