[ibis-macro] Minutes from the 7 Feb 2012 ibis-atm meeting
- From: Mike LaBonte <mike@xxxxxxxxxxx>
- To: IBIS-ATM <ibis-macro@xxxxxxxxxxxxx>
- Date: Fri, 10 Feb 2012 17:19:17 -0500
Minutes from the 7 Feb 2012 ibis-atm meeting are attached.
Mike
IBIS Macromodel Task Group
Meeting date: 07 Feb 2011
Members (asterisk for those attending):
Agilent: * Fangyi Rao
* Radek Biernacki
Altera: * David Banas
Ansys: Samuel Mertens
Dan Dvorscak
Curtis Clark
Arrow Electronics: Ian Dodd
Cadence Design Systems: Terry Jernberg
* Ambrish Varma
* Feras Al-Hawari
Celsionix: Kellee Crisafulli
Cisco Systems: Ashwin Vasudevan
Syed Huq
Ericsson: Anders Ekholm
IBM: Greg Edlund
Intel: Michael Mirmak
LSI Logic: Wenyi Jin
Maxim Integrated Products: Mahbubul Bari
Mentor Graphics: * John Angulo
Zhen Mu
* Arpad Muranyi
Vladimir Dmitriev-Zdorov
Micron Technology: * Randy Wolff
NetLogic Microsystems: Ryan Couts
Nokia-Siemens Networks: * Eckhard Lenski
QLogic Corp. * James Zhou
Sigrity: Brad Brim
Kumar Keshavan
* Ken Willis
SiSoft: * Walter Katz
Todd Westerhoff
Doug Burns
* Mike LaBonte
Snowbush IP: Marcus Van Ierssel
ST Micro: Syed Sadeghi
Teraspeed Consulting Group: Scott McMorrow
* Bob Ross
TI: Casey Morrison
Alfred Chong
Vitesse Semiconductor: Eric Sweetman
Xilinx: Mustansir Fanaswalla
The meeting was lead by Arpad Muranyi
------------------------------------------------------------------------
Opens:
--------------------------
Call for patent disclosure:
- None
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Review of ARs:
- None (may find some after review of minutes from last week)
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New Discussion:
Analog BIRD discussion:
- Arpad: We seem to be converging toward BIRDs 116 & 118
- We had a request to make BIRD 118 more general, not just for AMI
- I will have a proposal for that next week
- Arpad: We have slides about the boundary condition discussion started by
Scott McMorrow
- The thoughts and decisions documented in those slides will have to
be incorporated in the specification, most likely BIRD 116
- We still need to discuss BIRDs 144 and 145. It would be best to
separate the user defined corner idea out from BIRD 144 into BIRD 118
and discuss BIRD 144 as the direct connection of S-parameter models only
- Walter: I would like to give my presentation intended for the summit
- Ambrish: We can make termination changes for BIRD 144
- Feras: BIRD 144 allows for many corners
- Arpad: We should take out the user defined corners from BIRD 144 and
deal with it in BIRD 118
- Radek: We have discussed the slides about Scott's idea before
- Unity gain amplifiers are not needed
- Do we need to have BIRD 118 data in a separate file?
- Arpad: I have changes in mind about that
- The data could be at the bottom of the IBIS file, like package models
- Bob: The parameter passing syntax is AMI specific
- We should not be restricted to only AMI parameters
- Arpad: We are talking about generalizing that in the next version of
BIRD 118. Instead of a file name reference we could use the tree
root name as a reference to the data. The data could be in the
.ibs file or in an external file, just as it is done with the
package modeling in IBIS.
- Bob: BIRD 144 could also be generalized
AR: Arpad propose method to generalize BIRD 118
Walter showed his email with a summary of the IBIS Summit presentations
Walter showed his presentation intended for the summit but not shown there
- Summaries of existing analog BIRDs
- BIRD 122 overview
- Pre-defined subcircuits
- Walter added a D-A converter on slide 8
- Slide 10: Ambrish and Kumar added 50 ohm resistors to Touchstone output
- Other vendors take different approaches
- Slide 11: A new way to specify parameters would help
- SiSoft supports using BIRDs 116 and 118
- Fangyi: Would like series R at Touchstone Tx output
- Walter: With a value parameter that defaults to 0
- Ambrish: Do most vendors require this?
- Feras: BIRD 116 is general, anything can go in the black box
- Radek: What is the rationale behind the standardized subcircuit names?
- Walter: SiSoft will supply subckt files with these names
- Reserving a name prevents collision with other circuits using the same names
- Ambrish: We have to deal with that issue every day
- Radek: Usually you use directories to keep things separate
- Walter: The problem is when they are in the same SPICE deck
- Radek: Is there any rationale to the formation of the name "Thevenin"?
- Walter: AMI because it is for AMI
- Thevenin because it is equivalent to the actual circuits
- Radek: Thevenin can apply to many kinds of circuits
- Walter: I can come up with a more rational name
- Bob: The circuits for these names must be defined
- Feras: This is not a reserved name, just an example
- Radek: The best approach is the ISS external model
AR: Mike post Walter's updated presentation to ATM website
Arpad showed one of the slides related to the discussion with Scott
- Arpad: If ideal sources are used for the Tx D_to_A converter, the
unity gain E elements are not needed
- Radek: It should be up to the EDA vendor whether to include those
- Fangyi: The E element is not the same as a short
- Arpad: The circled "1" symbol in that drawing does not represent a
short. It represents an infinite input impedance and zero
output impedance unity gain ideal amplifier
- Fangyi: The E element may confuse model developers
- Arpad: Scott wants to insure the boundary condition is correct no
matter what the EDA vendor does outside this model
- We might simply write that into the spec
- James: We should have matching impedance at the RX load end
- Walter: Scott said E elements are not required when Touchstone is used
- Arpad: But only if the Touchstone data incorporates the effects of
the isolation amplifier.
- Arpad: The general solution in BIRD 116 would be better
- Deciding on hard-coded subcircuits is not working
- Ambrish: There does not seem to be support for BIRD 144
- Bob: I support it
- Arpad: We should handle this in two steps:
- Modify BIRD 144 and remove the user defined corners (putting it
into BIRD 118)
- Then discuss BIRD 144 as the direct connected Touchstone proposal
- Feras: This does not address the termination impedance
- Bob: That is a reference impedance, not termination
- Arpad: With [External Circuit] all ports are user defined and other
[External Circuit]s can be connected to implement the port
termination for the Touchstone [External Circuit]
- With [External Model] the ports are all reserved port names and
the port impedances are implemented by the EDA tool. In this
case we have to define in the specification how the s-param
model should be connected (terminated) in the EDA tool.
- Feras: Agree
- Bob: You just hook it up, there really is no issue
- Arpad: It must be documented
- Bob: We could standardize on 50 ohm reference impedance
- Arpad: We can't have unwritten assumptions
- The Touchstone model maker may have a different assumption than
the EDA tool vendor's implementation (assumption)
- Walter: To make BIRD 144 general we would have to specify that
- Bob: S11 tells what the reference impedance is
Meeting ended.
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Next meeting: 14 Feb 2011 12:00pm PT
Next agenda:
1) Task list item discussions
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IBIS Interconnect SPICE Wish List:
1) Simulator directives
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