IBIS Macromodel Task Group

Meeting date: 26 February 2019

Members (asterisk for those attending):
ANSYS:                        Dan Dvorscak
                            * Curtis Clark
Cadence Design Systems:     * Ambrish Varma
                              Brad Brim
                              Kumar Keshavan
                              Ken Willis
eASIC:                        David Banas
GlobalFoundries:              Steve Parker
IBM                           Luis Armenta
                              Trevor Timpane
Intel:                        Michael Mirmak
Keysight Technologies:        Fangyi Rao
                            * Radek Biernacki
                              Ming Yan
                              Stephen Slater
                              Maziar Farahmand
Mentor, A Siemens Business:   John Angulo
                            * Arpad Muranyi
Micron Technology:          * Randy Wolff
                              Justin Butterfield
SiSoft (Mathworks):           Walter Katz
                            * Mike LaBonte
SPISim:                     * Wei-hsing Huang
Synopsys:                     Rita Horner
                              Kevin Li
Teraspeed Consulting Group:   Scott McMorrow
Teraspeed Labs:             * Bob Ross

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:

- Randy to investigate if/why/how a clock waveform input might be used.
  - In progress.

- Michael M. to investigate if/why/how a clock waveform input might be used.
  - In progress.
  
- Michael M. to check with IP experts on whether DC_Offset is useful for Tx.
  - In progress.
  
- Mike L. to reach out to FEC presentation authors for more information.
  - 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 February 19
meeting.  Radek moved to approve the minutes.  Bob seconded the motion.
There were no objections.

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New Discussion:

Arpad reviewed an email he had sent to ATM and a new BIRD draft it introduced.
Arpad noted that during the 7.0 editorial process it was discovered that the
last example for Rx_Receiver_Sensitivity contained a negative value.  That
example was corrected for 7.0, but the editorial group felt a BIRD should be
written to correct some ambiguities in the parameter's definition.  Arpad
suggested the group review the draft during the meeting and create draft_2.

Arpad asked for comments on the Solution Requirements table.  Mike L. said the
requirements were fine, but suggested the name of the parameter be stated
explicitly.  Arpad made the change.

Arpad asked if the BIRD should refer to 6.1 as the baseline or adopt 7.0 as the
baseline.  Bob and Radek recommended referring to 7.0.  Arpad noted that he
would change the baseline section and page number references to those from 7.0.
He noted that the example with the negative value had already been fixed in 7.0.

In draft_1, the Other Notes: section was amended to state that "values of this
parameter shall be non-negative floating point numbers."  Bob noted that we
should be careful with this language, as an Increment or Steps Format might
contain negative steps.  Radek suggest the language, "For all Formats, the
resulting values of the parameter shall be non-negative..."  The group liked
this suggestion, and Arpad added it to draft_2.

Arpad noted the new Examples: section text describing the example.  He asked if
"reference voltage" should be elaborated, and noted that when this parameter was
introduced AMI only supported NRZ, and the reference would have been assumed to
be 0V.  Now, we support PAM4, so the PAM4_UpperThreshold, PAM4_CenterThreshold
and PAM4_LowerThreshold could be the "reference voltage".  Arpad also noted the
new DC_Offset BIRD introduced for DDR5 support (single ended support) might come
into play.

Arpad also noted that we have four examples, but only describe the first one.
Mike L. suggested adding a sentence stating that the remaining examples
demonstrate user settable examples using various Formats.  Bob also noted that
we should state that the value of the parameter is assumed to be 0V if it is
not present.  Arpad made both changes.

Ambrish asked why DC_Offset would be relevant to this.  He noted that DC_Offset
is passed into the model so it can create the single-ended waveform for internal
use if it wants it.  But the DC_Offset BIRD states that the model is supposed to 
return a differential waveform.  If the tool is working with the differential
waveform, then DC_Offset does not affect the reference voltage for
Rx_Receiver_Sensitivity.  Arpad suggested we could at least leave DC_Offset out
of this draft and revisit the discussion if and when the DC_Offset BIRD is
approved.  Radek suggested adding a discussion of "reference" to the
Description: section.  The group arrived at the following sentence:

   "The reference voltage is 0 V by default, unless defined by the
    PAM4_LowerThreshold, PAM4_CenterThreshold or PAM4_UpperThreshold
    parameters."

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

AR: Arpad to send draft_2 of the Rx_Receiver_Sensitivity clarification BIRD to
    the ATM list.

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Next meeting: 05 March 2019 12:00pm PT
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IBIS Interconnect SPICE Wish List:

1) Simulator directives