IBIS Macromodel Task Group

Meeting date: 13 September 2022

Members (asterisk for those attending):
Achronix Semiconductor:       Hansel Dsilva
Amazon:                       John Yan
ANSYS:                      * Curtis Clark
                            * Wei-hsing Huang
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 draft1 of the SPIM BIRD to the ATM list.
  - 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 August 30th
meeting.  Ambrish moved to approve the minutes.  Randy seconded the motion.
There were no objections.

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New Discussion:

Pre-driver PSIJ BIRD draft introduction:
Chulsoon reviewed a new BIRD draft introducing [Pre-driver PSIJ Sensitivity] as
a new keyword.  He noted that his team had presented on the topic at several
IBIS summits (presentation links included at the end of the BIRD draft), and we
could review those presentations if necessary.

He said the goal is more accurate PSIJ simulation with IBIS.  The keyword, along
with its two Sub-params Rising Edge and Falling Edge, provides the PSIJ
sensitivity in s/V for the rising and falling edges.  Chulsoon noted that one
requirement is that the pre-driver use the same power domain as the buffer, as
this is modeling a pre-driver effect based on fluctuations in the power rail
used by the IBIS buffer.  Randy said that the effect being modeled is non-
linear, but the assumption is that within a limited range of interest a single
value for each edge is a reasonable approximation.  Randy said one area where
they would like feedback is on how much detail and background on the derivation,
algorithms, etc., should be provided.  Arpad said he preferred that the BIRD
focus primarily on what will change in the specification.  He said the
Background: section could be used to provide more detail.  Since the Background:
section already provided links to the presentations, and they were sufficiently
rigorous, he thought it was sufficient.

Chulsoon said he would send the draft to the ATM list for review.

Bob asked whether Chulsoon's draft and Kinger's recent presentations on PSIJ
would have to be rationalized.  Chulsoon said he thought they were complementary
concepts and couldn't be combined.  He said his was for time domain and Kinger's
was for frequency domain.  Kinger said he thought they might be able to converge
if he included a DC point in his frequency domain approach.

PSIJ frequency domain proposal:
Kinger reviewed a BIRD draft related to his recent summit presentation:
 https://urldefense.proofpoint.com/v2/url?u=https-3A__ibis.org_summits_aug22_cai2.pdf&d=DwIGAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=DcQR-qLpQg5lIreuM6-NYECRIAFXt268PRNS5WO043M&m=_uAN_PAJludqj7WELaw_FGGl0FU9OwV9gRCWqWgihWIQFZ-pak4TquYwHdL8ahIg&s=S2DIhn4OMgrEU6RO0v9LsZ7OYMcd8VMExq2UVoiB-F0&e=  

Kinger introduced a new [PSIJ Sensitivity] keyword, which provides jitter
sensitivity values in s/V at different frequencies.  He said the goal was to take
into account the collective power noise in all the rails.  He said Chulsoon's
proposal was focused on pre-driver effects, and he thought the addition of a
0 Hz value in his proposal would be equivalent to Chulsoon's.

Kinger introduced a [PSIJ Sensitivity Group] keyword.  He said this came out of
discussions with Michael Mirmak about whether two things sharing the same power
rail might have different sensitivities.  For example, you might have PCIe_Gen4
or PCIe_Gen5 using different groups to specify different sensitivities.

Chulsoon said their investigation suggested that different values were necessary
for the rising and falling edges, and he wasn't sure whether the frequency
domain approach would handle that.  Randy noted that another difference was that
Kinger's approach was scoped under [Component].  Chulsoon's was scoped by
[Model], and separate sensitivities could be specified for each [Model].  With
Kinger's approach it is broken out by voltage rail, and the assumption is that
all models on that specific voltage rail have the same PSIJ sensitivity.

Arpad noted that IBIS is predominantly focused on time domain waveforms.  He
asked how Kinger envisioned this frequency domain information being used.
Kinger said that IBIS currently doesn't really cover the PI domain.  This new
PSIJ sensitivity data is being proposed assuming that a simulator will have been
able to generate information about the noise on each power rail.

Kinger said that for AMI simulations this PSIJ sensitivity could be incorporated
as a post processing step similar to the way random jitter is handled.

Kinger said he would work on cleaning up his proposal for further review at the
next meeting.

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

AR: Chulsoon to send the Pre-driver PSIJ Sensitivity BIRD draft to the ATM list.
    
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Next meeting: 20 September 2022 12:00pm PT
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IBIS Interconnect SPICE Wish List:

1) Simulator directives
