IBIS Macromodel Task Group

Meeting date: 13 October 2009

Members (asterisk for those attending):
  Adge Hawes, IBM
* 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
  Chris McGrath, Synopsys
* Danil Kirsanov, Ansoft
  David Banas, Xilinx
  Deepak Ramaswany, Ansoft
  Donald Telian, consultant
  Doug White, Cisco Systems
* Eckhard Lenski, Nokia-Siemens Networks
  Eckhard Miersch, Sigrity
  Essaid Bensoudane, ST Microelectronics
* Fangyi Rao, Agilent
  Ganesh Narayanaswamy, ST Micro
  Gang Kang, Sigrity
  Hemant Shah, Cadence Design Systems
  Ian Dodd, consultant
  Jerry Chuang, Xilinx
  Joe Abler, IBM
  John Angulo, Mentor Graphics
  John Shields, Mentor Graphics
  Ken Willis, Cadence Design Systems
  Kumar Keshavan, Sigrity
  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 Komow, Cadence Design Systems
  Richard Mellitz, Intel
  Richard Ward, Texas Instruments
  Samuel Mertens, Ansoft
  Sam Chitwood, Sigrity
  Sanjeev Gupta, Agilent
  Shangli Wu, Cadence Design Systems
  Sid Singh, Extreme Networks
  Stephen Scearce, Cisco Systems
* Steve Kaufer, Mentor Graphics
  Steve Pytel, Ansoft
  Syed Huq, Cisco Systems
  Syed Sadeghi, ST Micro
  Ted Mido, Synopsys
  Terry Jernberg, Cadence Design Systems
  Todd Westerhoff, SiSoft
* Vladimir Dmitriev-Zdorov, Mentor Graphics
  Vikas Gupta, Xilinx
  Vuk Borich, Agilent
* Walter Katz, SiSoft
  Zhen Mu, Mentor Graphics

------------------------------------------------------------------------
Opens:

- Arpad announced that Mike L. was not available today, and asked for
  any volunteers to take the meeting minutes.

- Arpad gave an overview of the schedule for the upcoming meetings:

  - Vladimir's presentation on including non-linear effects (today)
  - Discuss Walter's E-mail "An AMI Overview", sent Sat 10/10/2009
  - Discuss "Three new flow diagrams have been posted", posted Fri 10/9/2009
  - Walter Katz will prepare an AMI BIRD draft
  - Refine AMI BIRD draft
    - Add Computation DLL Entry 
    - Add LTI Reserved Parameters to AMI BIRD 
    - Add Vendor Requested Reserved Parameters to AMI BIRD 
    - Request for other changes to AMI BIRD 
  - Submission of AMI BIRD to IBIS Open Forum
  - Make a list of IBIS-ISS questions to be answered
    - Discuss/resolve questions
    - Submit IBIS-ISS document to IBIS Open Forum for review

--------------------------
Call for patent disclosure:

- No one declared a patent.

-------------
Review of ARs:

- Arpad send AMI flow diagrams to Mike L. to be posted on the web
  - Done

- Mike change web page to make items easily linkable
  - The pages no longer use frames
  - Next will try to make document URLs shorter
  - The minutes were broken for several months, but fixed now

- Arpad Write a clarification BIRD to discuss accuracy issues related to the 
  various AMI clock_tick algorithms in an IBIS-AMI DLL
  - TBD

- Todd: Update the BIRD for IBIS S-parameter box based on feedback from discussion
  - No update

- 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:

Vladimir gave a presentation on:  "How to account for non-LTI of Tx analog
buffer in IBIS AMI flow" which was followed by a questions and answers
session.

Walter thanked Vladimir for the presentation and thought it was excellent.
Danil:  What kind of non-linearities can be addressed by this, for example
  capacitors?
Vladimir: Capacitors use a discretized model which is converted to difference
  equations which can be used in non-linear situations like for I-V curves.
  We just need to pay attention to how the model is partitioned to not have
  any double counting of the capacitance.
Fangyi asked a question to which the response was:
  Equation 2 on slide 14 - model is like a general subcircuit, just a function
  call to get current.
Fangyi:  Non-linear questions are usually solved by Newton iteration.  Where
  would this be done, in the Tx DLL model or the EDA tool?
Vladimir:  It can be either in the Tx DLL model, or in the "Utility DLL" (which
  would not have to be written by the model maker).
Fangyi:  Does this Utility DLL actually become a simulator?
Vladimir:  No.  It is basically a function library.
Fangyi:  There are other types of methods, e.g. bi-section, to solve equations,
  and we also need controls for convergence, etc...
Vladimir:  These can be parameters to the function.  There are many ways to
  solve equations.
Fangyi:  Who generates these function?
Vladimir:  Model vendor
Fangyi:  Was the model used in the presentation an IBIS model?
Vladimir: The example was IBIS with I-V and V-t curves.  It is easier to solve
  the equations in the presence of the admittance matrix than just solve the Tx
  output alone.
Arpad:  How important is this capability?  Is it urgent to consider this to be
  included in the IBIS 5.1 specification?
Fangyi:  This situation is close to a three component channel model Tx-channel-Rx
  which is a general transient simulation
Walter:  We should not seriously consider this capability for the next IBIS version.
  IC vendors would not make models like this yet.
Fangyi:  Agree.
Arpad:  This is not like general transient simulation.
Vladimir:  This algorithm interacts with the Tx model's output only.  Regarding 
  model vendor not being able to write models like this, how do we know that the
  IBIS models currently used to generate impulse response are accurate enough?
  If we consider those accurate, this should be possible too.
Arpad:  Can the I-V and V-t curves of the IBIS model used for this capability?
Vladimir:  EDA can use those to make impulse response.
Walter:  Did you say that IBIS models can be accurate enough?
Vladimir:  Yes.
Walter:  Not true.  IBIS models are not accurate to generate impulse response.
Arpad:  What is used to generate impulse response then if not IBIS?
Walter:  Touchstone broadband models.
Vladimir:  Cannot tell how big is the error.
Walter:  These are wonderful discussion points.
Vladimir:  Slide 12:  Impulse response is not using Tx.  It can be 100% accurate
  with Tx GetWave.
Walter:  Agree.
Vladimir:  The biggest obstacle is the ability to model Tx
Walter:  This is a significant task to model makers (IC vendors)
Arpad:  If we waited for the need to arise to include this capability in the
  IBIS specification, it may be too late, considering the time needed to get
  a BIRD written and approved, and get the new IBIS specification ratified.
Walter:  This doesn't have to wait years.  Let's get the AMI corrections done
  first and then consider this.
Ambrish:  What are the complications considering cross talk?
Vladimir:  Cross talk is linear and a second order effect with respect to
  signal.  Don't think this will be effected by that, like jitter isn't either.
  We only need one cross talk vector per channel.  This proposal doesn't go into
  the details of the DLL interface, just wanted to show the concept of dealing
  with non-linearities.


AR: Arpad send Vladimir's presentation to Mike L. for posting

Next meeting: 20 Oct 2009 12:00pm PT

--------

IBIS Interconnect SPICE Wish List:

1) Simulator directives