IBIS Macromodel Task Group

Meeting date: 16 June 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
  Deepak Ramaswany, Ansoft
  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
  Samuel Mertens, Ansoft
  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

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Opens:

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Call for patent disclosure:

- No one declared a patent.

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Review of ARs:

- Todd: Write IBIS s-param BIRD
  - Still working on it

- 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: Is there any progress on IBIS-IS document edits?
- Walter: No changes have been made

Walter: We are functionally very close to finishing IBIS-IS
- Everyone supports the HSPICE subset we have defined
- The intent was to have EMD support general interconnect
  - It may be better to focus on packages and DIMMs
- One view is "here is a connector and the circuit to model it"
  - Another view is "here is a circuit and how it can be used for a connector"
- Brad Brim has sent an alternative proposal
  - Not sure if it was sent to many of us
  - Somewhat like EMD
  - Bob: The syntax is IBIS-like

Arpad: We had talked about the idea of a "signup sheet" but decided against it
- Walter: It would be good to know who will support IBIS-IS
- Arpad: Vendors probably will support it anyway
- Walter: We don't have to ask for a vote, just an informal yes/no
- Bob: In IBIS discussing product plans is out of bounds
  - As individuals some of us don't have company authority to comment on
    release content anyway
- Mike: There is currently no way to invoke IBIS-IS from IBIS

Removing all references to "HSPICE":
- Walter: We can just say it was extracted from the HSPICE manual
  - Our stuff will be in a separate document
- Arpad: A single document would be better
  - We had agreed to make the change in the editorial phase

Limited character set:
- Walter: Agree, this would make it easier to convert
- Arpad: We decided last week that the rules about '-' make sense
- Bob: We need an addendum for any changes we make to HSPICE
  - Radek: Agree, it would be better to not have special rules
- Arpad: ELDO has a switch make make it understand different syntaxes
- Walter: We could only recommend avoiding certain characters
- We agreed on this

Exponent limits:
- Arpad: We may need to describe this even if we do not support it
- Walter: Machines really do have these limitations
- Bob: There is a range that should be practical
- Walter: Resistors under 10e-5 ohms are a problem
- Radek: Exponent limits should not be in a subckt
- Arpad: Some spice tools have options others don't
  - PARHIER is a new HSPICE feature
  - It allows subckts to have local SCALE
  - Other tools may not have this
- Radek: We should at least say what the default is
- Walter: SCALE is LTI, so it could be a valid feature for IBIS-IS
- Arpad: Once had trouble with SCALE affecting a capacitance expression
  - The effect was unexpected
  - The expressions had nothing complicated in them
- Walter: Then we should not allow SCALE
  - It's about having confidence that a circuit will work in many tools
- Arpad: The subckt may be used in a circuit that uses SCALE
  - We would want to require subckt SCALE to be 1
- Mike: SCALE should not be used with externally imported subckts
  - Or the imported subckts should be forced to SCALE=1
- Walter: We should keep it simple
- Arpad: PARHIER can ruin efforts to make use of global variables
- Walter: That is a risk
- Bob: Do we support .PARAM within subckts?
  - Walter: Yes, it can be overridden by instance params
- Arpad: Should we support params on the subckt def line?
  - Walter: No
- We will not say anything about PARHIER in IBIS-IS
- Arpad: Will our subckts be immune to PARHIER?
- Walter: They should be
  - It is best to make the names very unique
- Arpad: With unique names PARHIER would have no effect
- Arpad: We will advise against using PARHIER
- Radek: We should not allow it
- Bob: .OPTION allowed in subckts?
  - Walter: No
- Bob: All options affect simulations
- Arpad: We have to specify that params other than what we support
  must have no effect
  - For example, resistors must not support temperature coefficients
- Walter: This process will take a long time if we pursue this level of detail
- Arpad: We should state that supporting feature that we do not specify
  may cause problems.

Next meeting: 23 June 2009 12:00pm PT

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IBIS Interconnect SPICE Wish List:

1) Simulator directives