[ibis-macro] Minutes from the 17 Mar 2009 ibis-atm meeting

  • From: "Mike LaBonte (milabont)" <milabont@xxxxxxxxx>
  • To: "IBIS-ATM" <ibis-macro@xxxxxxxxxxxxx>
  • Date: Tue, 17 Mar 2009 18:44:04 -0400

Minutes from the 17 Mar 2009 ibis-atm meeting are attached.

IBIS Macromodel Task Group

Meeting date: 17 March 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
  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
  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 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
* Ted Mido, Synopsys
  Terry Jernberg, Cadence Design Systems
* Todd Westerhoff, SiSoft
  Vladimir Dmitriev-Zdorov
  Vikas Gupta, Xilinx
  Vuk Borich, Agilent
* Walter Katz, SiSoft
  Zhen Mu, Cadence Design Systems


Call for patent disclosure:

- No one declared a patent.

Review of ARs:

- Todd: invite Synopsys to join us for a syntax review
  - Done, Ted Mido has joined us

- Todd:   Start a BIRD for IBIS s-params
  - Done

- 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:

Todd introduced Ted Mido from Synopsys

Chris asked about our document request:
- Chris: Are we looking for cut and paste capabilities?
- Walter: We can cut and paste from PDF, but that is painful
  - We only need the sections we selected for IBIS Interconnect SPICE
- Chris: We use FrameMaker to produce the documents
- Mike L: Does FrameMaker export to other formats?
  - Chris: Not sure
- Chris: Synopsys might not be willing to release full files
  - It may be painful for new Framemaker users to work with it anyway
- Arpad: We only need part of the documentation
  - Chris: I can ask if it can be exported
  - Mike L: Believe that Framemaker can save to MSWord and RTF
  - Todd: That should get us close
- Chris: I will ask about getting an MSWord version
  - Will send to Todd

Discussion of IBIS Interconnect SPICE subset of HSPICE:
- Walter summarized our task:
  - Almost all EDA tools read HSPICE to some degree
  - We are limiting significantly to elements needed for interconnect
  - Walter extracted the relevant syntax from the HSPICE PDF
  Walter showed his IBIS Interconnect SPICE document and described each page 
  - The next step is to add detail to each element
  - We ran into issues that need Synopsys to clarify
- S-element syntax:
  - Arpad: Direct call of file from S-element and .MODEL is a duplication
    - Chris: The .MODEL is convenient for many instantiations of a model
      - Instance keyords override .MODEL
    - Arpad: What if .MODEL is an S type and instance is a Y?
      - Chris: Haven't seen many Y parameters
        - The instance overrides, but need to double check
    - Arpad: Same question for FBASE and FMAX
      - Chris: The instance overrides
      - Arpad: Do FBASE and FMAX indicate the content that a .MODEL has?
        - Chris: FBASE and FMAX do not mean that
          - They limit the frequency range used in simulation
        - Walter: So these are like a filter?
          - Chris: Yes
    - Chris: Almost all simulators can use S-params in the time domain
  - Walter: What are the rules for S-element reference terminals?
    - Chris: There are 3 ways to specify S-param nodes
      - No reference node, global ground
      - Single reference node
      - Ref node for each terminal, doubles the number of terminals
  - Arpad: Do multiple reference nodes have to be at the same DC level?
    - Chris: HSPICE has no restriction on this
      - The reference node is only where the return current goes
    - Walter: What happens if the reference node is '0'?
      - Chris: That syntax is correct if N=4
      - Walter: Sxxx nd+ ref+ nd- ref- (N=2)
        - This would be for a diff pair
    - Arpad: If you don't assign a reference node the global is used
    - Walter: We can't tell if a TS1 s2p file has S21 or S12 data
      - Chris: HSPICE assumes it is S21
  - Arpad: Why does the S-element instance not have the TSTONEFILE param?
    - Chris: HSPICE does not support that, but it would be good
    - Mike L: We could add TSTONEFILE to the instance in our specification
      - The .MODEL could be autogenerated by tools as needed
- W-element syntax:
  - Arpad: Why is the S-param format here?
    - Chris: In the beginning S-params were used for simple T-lines
      - The W-element performs better with S-params than the S-element
        - It makes assumptions that make it more efficient
      - For IBIS, S and W are clearly separated
      - S parameters for the W-element should not be needed
  - Chris: Recommend dropping RLGCFILE support
    - It's easy to make mistakes
    - Arpad: People may have legacy RLGC files, so we should keep it
- Shunt element:
  - Walter: Shorts are neeed now and then
    - HSPICE has both .connect and V=0
    - Chris: No recommendation on this
- E F G H elements
  - Walter: We need linear delay, Laplace, Pole-Zero
    - What is Foster Pole-Residue?
    - Chris: Foster is a series of partial fraction models
      - There is increasing demand for this
      - Mike L: Do existing tools generate these?
        - Chris: Only one
    - Chris: Laplace is the most common format
  - Walter: What is the application for the Frequency Reposnse Table ?
    - Chris: This is an abitrary frequency dependence model
      - It should be OK to drop this and use S-param
    - Arpad: There is a similar feature for the W-element
- Walter: In HSPICE you can put a node in a param expression calculation
  - What does HSPICE do with this?
  - Arpad: Does it update dynamically?
  - Chris: It is updated throughout the simulation
  - Walter: We would forbid this
- Chris: The reserved frequency keyword HZ can be useful in expressions
  - Arpad: This is for frequency domain simulations
  - Chris: HZ is supported in time domain too
    - Arpad: What is the value in the time domain?
    - Chris: The same thing, based on S-param calculations
  - Chris: One problem is that using HZ can cause non-causal behavior
    - Maybe it would be better to not allow HZ
- Arpad: Complex numbers in expressions would be nice
  - Chris: Agree

Next meeting: 24 March 2009 12:00pm PT


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