IBIS Macromodel Task Group

Meeting date: 15 October 2024

Members (asterisk for those attending):
Achronix Semiconductor:       Hansel Dsilva
Altair:                       Junesang Lee
Amazon:                       John Yan
ANSYS:                      * Curtis Clark
                            * Wei-hsing Huang
Aurora System:                Dian Yang
                              Raj Raghuram
Cadence Design Systems:     * Ambrish Varma
                              Jared James
Dassault Systemes:            Longfei Bai
Google:                       Hanfeng Wang
                              GaWon Kim
Intel:                        Michael Mirmak
                              [Kinger Cai]
                            * Chi-te Chen
                              Liwei Zhao
                              Alaeddin Aydiner
                              Sai Zhou
Keysight Technologies:      * Fangyi Rao
                              Majid Ahadi Dolatsara
                              Stephen Slater
                              Ming Yan
                              Rui Yang
Marvell:                      Steve Parker
Mathworks (SiSoft):         * Walter Katz
                              Graham Kus
Micron Technology:            Justin Butterfield
Missouri S&T:                 Chulsoon Hwang
                              Yifan Ding
                              Zhiping Yang
Rivos:                        Yansheng Wang
SAE ITC:                      Michael McNair
Samsung:                      Jun-Bae Kim
Siemens EDA (Mentor):       * Arpad Muranyi
                            * Randy Wolff
Signal Edge Solutions       * Benjamin Dannan
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:

Yifan:  Perform additional investigations into the applicability of BIRD220.1
        for devices with independent pre-driver stages.
        - In progress.  Arpad noted that Yifan had created a new draft of
          BIRD220.1, and he had sent it out with the ATM agenda email.  He said
          Yifan had reported that she was still working on the additional
          investigations of devices with independent pre-driver stages.

Michael:  Prepare a new draft BIRD updating the language surrounding Ts4file and
          Ramp and related cross checking.
        - In progress.

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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 October 8th
meeting.  Ambrish moved to approve the minutes.  Arpad seconded the motion.
There were no objections.

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New Discussion:

BIRD220.1 update:
Arpad encouraged everyone to review Yifan's new (version 7) draft of BIRD220.1.

Randy asked to review some of the slides from Yifan's presentation at the ATM
meeting on September 10th.  Arpad shared the slides, which Yifan had sent to the
ATM list after the meeting on September 10th.  Randy reviewed slides 8, 9, and
10, which show the gate_p, gate_n, and pad waveforms when driving into 50 Ohms
to Vcc, 50 Ohms to GND, and 20pF to GND respectively.  He noted that for the two
resistive loads (slides 8 and 9) the gate waveforms were essentially identical,
but the gate waveforms changed appreciably for the capacitive load (slide 10).
Randy said he did not expect to see the change in gate waveforms for the
capacitive load.  He said that that the only connection to the test load would
be through the gate to source or gate to drain capacitance.

Fangyi asked about the pad waveforms in slide 8 (50 Ohms to Vcc).  He found it
odd that the output waveforms at the pad did not diverge until near saturation
at the top of their range.  The rising edges appeared identical until the values
diverged at the top of the range.  The group reviewed the test setup
information, and Arpad suggested that this behavior likely resulted from the
load being 50 Ohms to Vcc nominal, while the Vddq was swept.  So, the resulting
waveforms were similar to those seen in the "plateau" experiments when driving a
load into Vddq/2.  The rising edge was largely defined by the turnoff of the
pulldown device, at which point the pad waveform was pulled to Vcc nominal by
the test load.  Once the pullup device turned on, the pad waveform was pulled
toward the Vddq value.  Randy agreed that this was the likely explanation, but
he said that driving into a fixed Vcc nominal likely obscured the PSIJ effects
the experiment was trying to demonstrate.  Since V_fixture was nominal Vcc not
Vddq, you have two different power supplies fighting each other.  Randy and
Arpad suggested that driving into Vddq or Vddq/2 would be more meaningful.
Randy agreed to update Yifan on the discussion and ask her to redo the 50 Ohm to
Vcc experiment into Vddq instead.  Randy said he would also like to see a 4th
column added to the slides to show the output waveforms for a power-aware IBIS
[Model] driving into the same loads.

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

New ARs:

Randy:  Update Yifan on the discussion in the meeting and ask her to redo the
        50 Ohms to Vcc experiment into Vddq instead.

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Next meeting: 22 October 2024 12:00pm PT
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IBIS Interconnect SPICE Wish List:

1) Simulator directives
