IBIS Macromodel Task Group

Meeting date: 14 September 2021

Members (asterisk for those attending):
Achronix Semiconductor:       Hansel Dsilva
Amazon:                       John Yan
ANSYS:                      * Curtis Clark
                            * Wei-hsing Huang
Cadence Design Systems:     * Ambrish Varma
                              Ken Willis
                              Jared James
Google:                       Zhiping Yang
Intel:                        Michael Mirmak
                              Kinger Cai
                              Alaeddin Aydiner
Keysight Technologies:      * Fangyi Rao
                              Radek Biernacki
                              Ming Yan
                              Todd Bermensolo
                            * 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
Siemens EDA (Mentor):       * Arpad Muranyi
Teraspeed Labs:             * Bob Ross
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:

- Chulsoon to email his presentation to ATM.
  - 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 September 14th
meeting.  Randy moved to approve the minutes.  Lance seconded the motion.
There were no objections.

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New Discussion:

PSIJ modeling:
Randy noted that Micron is looking at some buffers to characterize PSIJ and see
if they can provide recommendations for the BIRD Chulsoon may create.  He said
we may need to more precisely specify how you measure the [PSIJ] value (test
loads, voltage levels, etc.).  Bob asked whether it might make sense to have
[PSIJ] values under different load conditions, perhaps the load conditions for
the various rising and falling waveforms.

Randy said he expects to be able to share some data and assemble a presentation
in the future.  He said they had characterized one driver and looked at the
linearity of the PSIJ value.  He said it would be interesting to see how well
a single PSIJ value fits the full PSIJ plots they had created.

Arpad noted that Walter had suggested alternate uses of the [PSIJ] keyword data,
for example, the EDA tool could shift the edges of the stimulus waveform input
to Tx GetWave.  Arpad asked whether we should consider adding text to that
effect or should deal with that as a separate AMI Reserved Parameter.  Bob
thought we'd want to keep them separate.  Randy said it was an interesting
question, and you might want to put the same measurement value in both places.
Bob said it might not be obvious how to map information from a PSIJ keyword
with typ/min/max, etc., into use in AMI.

DDR5 Modeling updates:
Arpad asked Randy and Justin about any updates/issues.  Justin said they are
providing some early DDR5 AMI models.  He said things are working, but they are
eagerly awaiting the release of 7.1.  He said once EDA tools support 7.1
features we will be okay for now.

GDDR6x update:
Randy said he had nothing new to report.  He said he had given Walter some
additional details on the GDDR6x buffer so he could think about AMI improvements
that might be useful.  Randy said he wanted to do more characterization of the
equalization in the GDDR6x Tx and see how badly it breaks any AMI assumptions.
Randy said it will probably be a while before he has a new update.

Review of Tabled Topics List:
Item 10 - Old Redriver flow proposals/BIRDS:
The group decided this could be removed, as we don't expect to revisit any of
these given the progress of BIRD211.3.
    
Item 13 - Other DDR5 related topics:
Bob suggested we keep this topic.  Randy said EDA tools have different ways of
dealing with rise/fall asymmetry.  He said that as they've tested out their DDR5
models in various tools they've observed different waveforms passed into
GetWave.  Arpad said he'd wondered whether we need to extend AMI so that it has
two IRs or possibly a pulse response.  Ambrish said he thought we had settled
this and agreed that rise/fall asymmetry could be handled by tools without
changing AMI.  The group agreed this topic could stay on the list.

Item 14 - New BIRDs from Editorial Task Group?
Bob said these are still important topics, but addressing them would span all of
IBIS, and they hadn't had time.  The group agreed this could stay on the list.

Item 15 - Missing min/max data?
Arpad said this still and issue, but he hadn't spent any more time on it.  The
group agreed this could stay on the list.

Pending BIRDs awaiting discussion:
Bob suggested that we remove the "TBD" entry and leave the other two BIRDs
there on the list until the Open Forum votes them down.  The group agreed.

Topic bin list:
The fourth item on the list, referencing issues, was moved to become entry e
of item 14 in the Tabled Topics.  All other items were left in place.

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

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Next meeting: 28 September 2021 12:00pm PT
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IBIS Interconnect SPICE Wish List:

1) Simulator directives