IBIS Macromodel Task Group

Meeting date: 16 December 2008

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:

- Arpad: This will be our last meeting this year.
  - The next meeting will be 6 Jan 2009

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Call for patent disclosure:

- No one declared a patent.

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Review of ARs:

- Michael M:  Confirm with Synopsys whether "used by permission" can be used
              as the official indicator on relevant documents.
  - Todd: An email went out. No status known yet.

- 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

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New Discussion:

Arpad read from his outline:
- 1) There are three IBIS communities:
  - EDA vendors
    - Would like fewer changes
  - IC designers
    - Need to model circuit details
  - System designers
    - Need accurate models
    - Don't care about internal details
- 2) Dilemma: easy extraction vs. language freedom
  - Language freedom does not necessarily mean complexity
- 3) The modeling language should not specify how to extract the model
  - IBIS inflexibility causes it to influence the extraction methods
- 4) Dilemma: Implementation vs. cost
  - We tend toward large implementations
- 5) IP protection must be considered
- John Angulo's 3 issues:
  - a) How to assign models
  - b) How to simulate them
    - Most models come in the form of coefficients for pre-defined models
    - We might come up with better ways to describe pre-defined models
  - c) How to interpret results

- Walter: On issue #3, IBIS is measurement-based
  - The premise that measurement is required poses the difficulty
  - What is a B element?
    - Is it's purpose to be used for time domain simulation?
- Arpad: Would like a more general purpose capability
- Bob: The modeling currently is strongly time domain
 - Frequency domain is a nice addition
- Todd: Talking about the B element restricts this to present IBIS
- Arpad: IBIS can be used in the frequency domain today
- Walter: We have been talking about table vs. equation models
  - We could have procedural models
    - Should we use DLLs?
  - The B element has failures regarding differential and >3GHz speeds
- Arpad: Why not use high level languages?
  - Michael M: We may not need a "nuclear powered fly swatter"
    - When table models become too involved, then it is OK to switch
- Arpad: Michael M sent an email about System C vs. VAMS
  - Is this a possible replacement?
  - Todd: When IBIS started we accepted the abstraction it proposed
    - AMS allows any level of abstraction
    - But we may be setting ourselves up for failure
    - Is our charter to do a few things well or to do everything?
- Bob: We could limit our solution to the high end
- Todd: If we had a connectivity and block language we would have gone farther
  - SPICE, for example
- Michael M: We tend to shift the burden of figuring things out to EDA vendors
  - AMS assumes familiarity with languages
  - EDA vendors do not always implement everything
- Todd: The 3 markets are really 1 market
  - The system design market "funds" all 3 groups
  - Michael M: The system designers just want something that works
- Arpad: Any language subset we choose will run out of steam
  - Todd: Even SPICE is limited
    - Kumar pointed out that we need a general purpose interconnection mechanism
- Bob: If we have a language solution will we target a single "perfect" language?
  - Low end IBIS is in place now
- Mike L: Walter brought up DLL models but switched to languages
  - Arpad: It may take a big language to cover all capabilities
- Walter: IBIS needs to:
  - Deprecate and remove things from the IBIS spec that are not needed
  - Add support for differential and high speed buffers
  - Better handle s-params (sparse Touchstone)
  - Somehow handle industry standard measurement rules
  - Define a DLL interface for sophisticated users
  - Solve packaging (should not require a whole new language)
- Arpad: This is on top of existing IBIS
  - Walter: Yes, we are successful with IBIS at 15GHz
  - Anything else will take years to develop

Next meeting: 6 January 2009 12:00pm PT

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