IBIS Macromodel Task Group

Meeting date: 28 February 2023

Members (asterisk for those attending):
Achronix Semiconductor:       Hansel Dsilva
Amazon:                       John Yan
ANSYS:                      * Curtis Clark
                            * Wei-hsing Huang
Aurora Systems:             * Dian Yang
Cadence Design Systems:       Ambrish Varma
                            * Jared James
Google:                       Hanfeng Wang
                              GaWon Kim
Intel:                        Michael Mirmak
                            * Kinger Cai
                              Chi-te Chen
                              Alaeddin Aydiner
Keysight Technologies:        Fangyi Rao
                              Majid Ahadi Dolatsara
                              Ming Yan
                              Radek Biernacki
                              Rui Yang
Luminous Computing            David Banas
Marvell                       Steve Parker
Mathworks (SiSoft):           Walter Katz
                              Mike LaBonte
Micron Technology:          * Randy Wolff
                              Justin Butterfield
Missouri S&T                  Chulsoon Hwang
                              Yifan Ding
Rivos                         Yansheng Wang
SAE ITC                       Michael McNair
Siemens EDA (Mentor):       * Arpad Muranyi
Teraspeed Labs:             * Bob Ross
Waymo:                        Zhiping Yang
Zuken USA:                  * Lance Wang

The meeting was led by Arpad Muranyi.  Curtis Clark took the minutes.

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Opens:

- None.

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Review of ARs:
  
- Kinger to send out draft7 of the PSIJ Sensitivity BIRD containing changes
  reviewed and discussed in the February 21 meeting.
  - Done.

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Call for patent disclosure:

- None.

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Review of Meeting Minutes:

Arpad asked for any comments or corrections to the minutes of the February 21st
meeting.  Kinger moved to approve the minutes.  Dian seconded the motion.
There were no objections.

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New Discussion:

Standard Power Integrity Model (SPIM) BIRD draft:
Kinger reported that he had received no new feedback on draft9.  Arpad asked
whether the 40-character limit specified for various file name quantities was
consistent with what was done in IBIS 7.2.  Bob, Randy and Arpad said the 40
character limits defined for keywords that contain names, e.g., [Device SPIM
Group] were consistent with existing usage.  However, for file name keywords
and subparameters, e.g., the File_TS subparameter of [SPIM Touchstone File],
the 40-character limit should not be explicitly stated.  Instead, as is done
in IBIS 7.2, the file name quantities should rely on the global definition
provided in Sections 3.1 and 3.2.  Kinger said he would remove the explicit
40-character limit from the file name related quantities in the BIRD.

Bob suggested that the file names in the Example sections be shortened to make
the examples easier to read.

PSIJ Sensitivity BIRD draft:
Kinger and the group reviewed draft7.  Kinger noted that the [PSIJ Sensitivity
Group] Description and Usage Rules had been updated to incorporate language
consistent with that used in [Interconnect Model Group] sections, per a
suggestion from Arpad and Randy at the previous meeting.

Bob expressed concern that name of the keyword [PSIJ Sensitivity Group] itself
could cause confusion.  He said in other contexts we use "group" keywords to
reference groups of "sets".  Arpad asked if naming it [PSIJ Sensitivity Set]
would be more consistent with other usage in the specification.  Randy agreed
that it was more like a set, but he said he wasn't sure we'd want to use set
in this context either.

Randy asked if a [PSIJ Sensitivity Group] name would always correspond to a
particular mode of operation (e.g., PCIe Gen4 or PCIe Gen5).  Kinger said yes.
He said, for example, a device might have three power rails.  Different groups
could specify the PSIJ Sensitivity for the rails differently for each mode.  Bob
said that [PSIJ Sensitivity Group] is essentially a selector.  Kinger said he
was open to suggestions for alternative names for [PSIJ Sensitivity] and [PSIJ
Sensitivity Group].

Bob and Arpad said we might have to think about where the [PSIJ Voltage List]
exists in the keyword hierarchy.  Is it scoped by [Component] or within one of
the PSIJ Sensitivity keywords?

Kinger reviewed a presentation on PSIJ Sensitivity from last year's Asian IBIS
Summits, and he described the overall goal.  He said that traditionally SI and PI
design and optimization had been done separately, and timing budgets for the SI
simulation and noise budgets for the PI simulation were used independently.  He
said when systems were slower and the unit interval was longer, these types of
targets and budgets could be defined and met at a reasonable cost.  Now,
however, with higher speed devices, designing systems based on simplistic noise
and timing budgets can be very expensive or impossible.  We need a more holistic
approach to SI/PI design.  SI/PI cosimulation would be ideal, but incorporating
transistor level models, full PDN models, and an SI simulation sufficient to
determine low BERs is almost impossibly time consuming.

With the SPIM BIRD and the PSIJ Sensitivity BIRD, the goal is to bring PI and
SI simulation closer together.  The SPIM BIRD supports AC analysis and DC IR
drop analysis for full PDN design and verification.  In the future, the goal is
to add SPIM model data to support transient simulation.  At that point, SPIM
could also help simulators compute the power rail noise in a transient
analysis.  The power rail noise from the transient PI simulation can then be
combined with the PSIJ Sensitivity data to compute Jitter to be applied in the
SI simulation.

- Curtis: Motion to adjourn.
- Randy: Second.
- Arpad: Thank you all for joining.

AR: Kinger to send out draft10 of the SPIM BIRD containing changes reviewed and
    discussed in today's meeting.
AR: Kinger to send out draft8 of the PSIJ Sensitivity BIRD containing changes
    reviewed and discussed in today's meeting.
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Next meeting: 07 March 2023 12:00pm PT
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IBIS Interconnect SPICE Wish List:

1) Simulator directives
