IBIS Macromodel Task Group

Meeting date: 15 November 2022

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:

-  Arpad to submit the latest clock_times clarification BIRD draft to the IBIS
   Open Forum as an official BIRD.
   - Done.  Submitted as BIRD222.

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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 November 8th
meeting.  Randy moved to approve the minutes.  Lance seconded the motion.
There were no objections.

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New Discussion:

Standard Power Integrity Model (SPIM) BIRD draft:

Kinger reviewed the latest draft of the proposal.  He reported that he had
incorporated the fix Arpad and Bob had suggested at the last meeting.  The
File_IBIS-ISS Sub-Param of [SPIM Rnetwork File] now specifies the subcircuit
name as well as the file name, as is the case for existing usages of
File_IBIS-ISS in IBIS 7.1.  Randy observed that the example had been corrected,
but he said the Usage Rules for [SPIM Rnetwork File] would also have to be
updated to reflect the change.

Bob asked whether it was correct to have [SPIM Voltage List] under
[SPIM Rnetwork File] in the hierarchy.  Kinger said it was.  He said
[SPIM Voltage List] is provided for DC IR drop simulations only, and it is
properly scoped inside [SPIM Rnetwork File].  It is not needed for AC
simulations with [SPIM Touchstone File], for example.

The group provided other editorial feedback, including:
 - File_IBIS_ISS -> File_IBIS-ISS
 - S parameters -> S-parameters
 - [End SPIM Chip Group] -> [End Chip SPIM Group]
 - Remove "Intel" from the [Manufacturer] Usage Rules example
 
Kinger said he would update the draft with the changes discussed in the meeting
and send the new version out to the ATM list for further review.

PSIJ Sensitivity BIRD:
Kinger noted that Michael Mirmak had been added to the Requestor list.  He
invited anyone else interested in advancing this proposal to join the list.
Kinger reviewed changes in the latest version, draft2.  He said the majority of
the changes relative to draft1 were in the Introduction section.  Derivation
details, equations, and figures from recent IBIS Summit presentations are
included in the Introduction.

In the Solution Requirements section, a new Table of IBIS Keywords and
Sub-Params had been added.

Kinger said [PSIJ Sensitivity Group] is analogous to [Model Selector].  A single
DDR controller might work for multiple standards, or a single PHY might support
multiple protocols.  The power rails might be the same, but PSIJ sensitivity
would be different for each different protocol or standard.  Each PSIJ
Sensitivity Group would specify all the power rails for the I/O interface
operating in a particular mode.

For the [PSIJ Sensitivity] keyword, Kinger reviewed the example and the
accompanying Figure 2.  He said we need to describe how the model maker should
choose the frequency data points to provide in the table.  He said the goal is
for the model maker to provide the worst-case envelope for PSIJ sensitivity, not
to duplicate the fine structure in the data.  Randy noted that the example's
figure seemed to indicate a spline or something other than a simple PWL was used
to fit the data provided in the table.  He suggested the BIRD should provide
more information if a specific type of fitting is expected from the EDA tool.
Arpad noted that one example used comma as the thousands separator character
(e.g., 10,000), and he said he wasn't sure if IBIS supported that format for
the numbers.  He suggested Kinger use scientific notation in the example.

Bob noted the use of [Voltage List] in this BIRD might be problematic because
it appeared in a different scope than the existing [Voltage List] in IBIS 7.1.
Bob said that in EMD the [Voltage List] is completely optional, and the model
maker can decide whether or not to include any particular rail.  Kinger said
[Voltage List] is required in this BIRD, and it must contain the name of any
power rail listed inside any PSIJ Sensitivity Group.  He noted, however, that
it is legal to have rails specified in [Voltage List] that do not appear in
any PSIJ Sensitivity Group.  He said a particular rail might be negligible for
PSIJ sensitivity, or it might not appear in a particular PSIJ Sensitivity Group.
Since the usages are different, Kinger asked whether we could resolve the issue
by proposing a new keyword name, [PSIJ Voltage List], with this BIRD.  Bob said
this might be the solution, but we have to think about it.

Kinger said he would create a new version incorporating the changes discussed
in the meeting and send it to the ATM list for further review.

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

AR:  Kinger to send an update (draft5) of the SPIM BIRD to the ATM list.
AR:  Kinger to send an update (draft3) of the PSIJ Sensitivity BIRD to the ATM
     list.
    
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Next meeting: 22 November 2022 12:00pm PT
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IBIS Interconnect SPICE Wish List:

1) Simulator directives
