IBIS Macromodel Task Group

Meeting date: 25 November 2014

Members (asterisk for those attending):
Altera:                     * David Banas
ANSYS:                      * Dan Dvorscak
                            * Curtis Clark
Avago (LSI)                   Xingdong Dai
Cadence Design Systems:       Ambrish Varma
                              Brad Brim
                              Kumar Keshavan
                              Ken Willis
Ericsson:                     Anders Ekholm
IBM                           Steve Parker
Intel:                      * Michael Mirmak
Keysight Technologies:      * Fangyi Rao
                            * Radek Biernacki
Maxim Integrated Products:    Hassan Rafat
Mentor Graphics:            * John Angulo
                            * Arpad Muranyi
Micron Technology:          * Randy Wolff
                              Justin Butterfield
QLogic Corp.                  James Zhou
                              Andy Joy
eASIC                         Marc Kowalski
SiSoft:                       Walter Katz
                            * Todd Westerhoff
                            * Mike LaBonte
Synopsys                      Rita Horner
Teraspeed Consulting Group:   Scott McMorrow
Teraspeed Labs:               Bob Ross

(Note: Agilent has changed to Keysight)

The meeting was led by Arpad Muranyi.

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

- Arpad showed a proposed meeting schedule through January.
  - We agreed to not meet Dec 16, 23, and 30.
  - January 27 would also be canceled due to DesignCon.


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

- None


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

- Todd produce slides for co-optimization requirements discussion.
  - Hoping to show something Dec 9.

- Arpad to review IBIS spec for min max issues.
  - In progress.


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

C_comp improvements:

- Arpad: This will be discussed in interconnect meetings, but we can discuss Walter's BIRD proposal here.
- Arpad showed Walter's Final Stage Subckt BIRD proposal.
- Radek: Did Walter send another C_comp document?
- Arpad: That was an email.
- Arpad showed an email from Walter Katz.
- Arpad: Walter describes a simple change if two assumptions can be made.
  - I'm not sure about the second assumption.
- Radek: We need to decide the meaning of V-T tables going forward.
  - We may have a problem depending on how V-T tables handle RLC elements.
  - On-die interconnect may include coupling, that would be a problem.

- Arpad: IBIS does not specify where C_comp is measured.
- Radek: It was not discussed much, but packages were excluded.
- Arpad: It should be possible to reverse engineer pad waveforms from pin waveforms.
  - The same can be done for buffer pad from package pad.
  - With on-die interconnect present it's not clear which pad C_comp belongs to.
- Randy: Compensation happens at model level.
  - So it has to be on the model side.
- Arpad: I'm not sure Final Stage Subckt was intended for model level.
- Randy: It allows for differential models.
- Arpad: There is a question if this would allow series connections between traces.
  - The new terminal names make that seem possible.

- Arpad: It's not clear what "Branch C_comp" is, we would need an explanation from Walter.
- Michael M: That might be about pole-zeros.
- Arpad: That proposal came out in 2003.
- Michael M: I proposed a multi-element solution at PCB East.
  - This was for frequency-dependent behavior.


Redriver BIRD:

- Fangyi: There has been no new progress.
  - It depends on communication with Walter.


IBIS-AMI directionality:

- Michael M: I think we need a BIRD but Walter disagreed.
  - Walter had a proposal but there is no BIRD for it.
  - Arpad: There was talk about making a model either a driver or receiver.
- Michael M: We need to identify in the AMI file if a model is in or out only.
  - Also we need to say how the enable signal would control AMI.
  - Also transitions from one mode to another have no temporal data.
  - It might relate to power calculations.
- Todd: The analytical method for that might not be valid.

- Michael M: BIRD 161 is pending resolution in the interconnect committee.
  - That one is about incomplete models.

Tabled BIRDs:

- Arpad described each tabled BIRD.
- Michael M: #13 might be for the quality committee.
  - We need a common numbered error code list for checks related to this.

- Radek: We might not have enough for next week.
- Arpad: We can have a meeting even if it's a short one.

-------------
IBIS Interconnect SPICE Wish List:

1) Simulator directives