Minutes from the 15 Aug 2017 ibis-atm meeting are attached.
The following document discussed in the meeting has been posted to the ATM
work archive:
DATE
AUTHOR <http://ibis.org/atm_wip/archive-author.html>
ORGANIZATION <http://ibis.org/atm_wip/archive-org.html>
TITLE <http://ibis.org/atm_wip/archive-title.html>
FORMATS
15-AUG-2017
Radek Biernacki
Keysight Technologies
BIRD 158.6 draft 3
(zip
<http://ibis.org/atm_wip/archive/20170815/radekbiernacki/BIRD_158_6_draft_
3.zip> )(docx
<http://ibis.org/atm_wip/archive/20170815/radekbiernacki/BIRD%20158.6%20dr
aft%203/BIRD_158.6_draft3.docx> )
One other document will be posted when ready.
Mike
IBIS Macromodel Task Group
Meeting date: 15 August 2017
Members (asterisk for those attending):
ANSYS: Dan Dvorscak
Curtis Clark
Broadcom (Avago): Xingdong Dai
Bob Miller
Cadence Design Systems: * Ambrish Varma
Brad Brim
Kumar Keshavan
* Ken Willis
eASIC: David Banas
Marc Kowalski
Ericsson: Anders Ekholm
GlobalFoundries: Steve Parker
IBM Luis Armenta
Trevor Timpane
Intel: * Michael Mirmak
Keysight Technologies: Fangyi Rao
* Radek Biernacki
Ming Yan
Maxim Integrated Products: Hassan Rafat
Mentor, A Siemens Business: John Angulo
* Arpad Muranyi
Micron Technology: * Randy Wolff
Justin Butterfield
SiSoft: * Walter Katz
Todd Westerhoff
* Mike LaBonte
Synopsys: Rita Horner
Kevin Li
Teraspeed Consulting Group: Scott McMorrow
Teraspeed Labs: * Bob Ross
TI: Alfred Chong
The meeting was led by Arpad Muranyi.
--------------------------------------------------------------------------------
Opens:
- Arpad: We might discuss unused interconnect terminals.
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Review of ARs:
- Radek to update the AM2 version of BIRD158.6 draft 2 to create a draft 3.
- Almost done, can show something today.
--------------------------
Call for patent disclosure:
- None.
-------------------------
Review of Meeting Minutes:
- Arpad: Does anyone have any comments or corrections? [none]
- Walter: Motion to approve the minutes.
- Randy: Second.
- Arpad: Anyone opposed? [none]
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New Discussion:
BIRD166.4:
- BIRD158.6:
- Radek showed his updated BIRD 158.6 draft 3.
- Radek described the changes, noting that previous change markup had been
accepted. The TX figure shown previously has been updated, changing
the source and adding pad and pin. The text is somewhat modified too.
The Rx figure is also modified, similarly to the Tx. The Rx text is only
slightly modified. The AMI flow figure is modified to remove the box tying
channel to packages. The AMI flow text is heavily modified to specify
that Ts4file is for die only. New parameters Ts4file_Package_Options and
Ts4file_Package_Data are added.
- Arpad: Is that renamed? It was Boundary before.
- Radek: These are new parameters.
- Arpad: They should not be called "new parameters" here. That may seem
awkward in a few years.
- Radek: Agree, I will change it.
- Bob: It would help to have "draft 3" inside the document. Why have
Boundary when we already have the directive? Do they work together or not?
- Arpad: Could they conflict?
- Radek: It is explicitly illegal to have both.
- Bob: This replaces the [Model] keyword.
- Arpad: I'm not sure we should be able to move the boundary to the pin here.
- Radek: The models for both might be in one file.
- Arpad: Package and die are usually extracted separately.
- Walter: This is an area of premature optimization. The package model
could be a short. We should work with the package model we have.
- Arpad: If the IBIS file has non-zero package model what happens?
- Radek: It explicitly says to ignore that if the AMI file has it.
- Arpad: If there is coupling in the IBIS file we can't ignore the coupling.
- Bob: If AMI defines package model syntax, that complicates AMI.
- Walter: AMI has no concept of package models. We should remove the pin
option from this. BIRD 189 can provide this capability.
- Radek: I would like people to review this BIRD draft.
- Ken: Does this relate to power connections?
- Radek: No
- Arpad: It is limited to 4 port models.
- Ken: Does this preclude modeling power parasitics?
- Radek: No IBIS still covers that.
- Arpad: If the power system can influence it then we have a non-LTI system.
- Walter: We would need to clarify that there is no power coupling.
- Ken: This can already be done with [External model], no BIRD needed.
- Walter: IC vendors do not like [External model].
- Radek: Ambrish might weigh in on this.
- Walter: One use for [External Model] is handling additional reactive
elements. But SerDes vendors are using Touchstone to handle T-coils.
- Ambrish: Does this take precedence over External Model?
- Radek: AMI takes precedence.
- Walter: This applies to impulse matrix calculation for crosstalk
terms. Pin to buffer coupling needs to be handled there. The package
introduces crosstalk.
- Arpad: It specifies 4 port s-parameters. You can't do coupling.
- Walter: You can't do on-die coupling.
- Arpad: Then not package either.
- Walter: The pin boundary should be removed from this BIRD.
- Radek: It might not be a prevailing use, but there is no harm to have
it. Bob Miller wanted to give package data. This was put in for posting
so that we can decide.
- Bob: Are coupled package models used for AMI?
- Walter: Yes.
- Ken: Interposers can be in the string too.
- Walter: That might be EBD, someday EMD.
AR: Radek send updated BIRD 158.6 draft 3
C_comp_model_Using_IBIS_ISS_BIRD:
- Randy showed C_comp_model_Using_IBIS_ISS_BIRD_rev1_WIP.docx
- Randy: The Mode rules have been updated. This might be handed similar
to submodel, with driving and non-driving modes.
- Arpad: Would there need to be two models?
- Walter: When driving you have VT curves, otherwise only IV. Really there
are two models. So far we have used [Model Selector] for this. That is
supported today.
- Bob: Not every tool supports [Model Selector], we have Model_type I/O for
this. I don't recommend [Model Selector] for this. C_comp can be different
across the modes.
- Walter: [Model Selector] handles that. Each [Model] has its own C_comp.
- Bob: This would allow bringing in different C_comp models. This resolves
the problem that the receiving point is not the driving point.
- Radek: There is a third option, to have both.
- Bob: In some DDR devices terminators are switched in only for receiving mode.
- Arpad: I would like the "all" mode. If the same model is used for both
modes it would be better not to need to duplicate the model.
- Randy: Tools already deal with models that only have pullup/pulldown
references defined. connect the pullup and pulldown terminals to the clamps.
- Mike L: Does this need to handle transitions from driving to non-driving
states?
- Michael M: We should consider IBIS handling protocol sensitive simulations,
but it's not easy.
AR: Randy to send C_comp_model_Using_IBIS_ISS_BIRD_rev1_WIP.docx to Mike L for
posting.
- Walter: Motion to adjourn.
- Arpad: Second.
- Arpad: Thank you all for joining.
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Next meeting: 22 August 2017 12:00pm PT
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IBIS Interconnect SPICE Wish List:
1) Simulator directives
