[ibis-macro] Minutes from the 20 Mar 2012 ibis-atm meeting
- From: Mike LaBonte <mike@xxxxxxxxxxx>
- To: IBIS-ATM <ibis-macro@xxxxxxxxxxxxx>
- Date: Tue, 27 Mar 2012 14:52:58 -0400
Minutes from the 20 Mar 2012 ibis-atm meeting are attached.
Mike
IBIS Macromodel Task Group
Meeting date: 20 March 2012
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:
- None
--------------------------
Call for patent disclosure:
- None
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Review of ARs:
- Mike post GetWave_Exists presentation to work archive
- Done
- Arpad send suggested GetWave_Exists wording changes to 5.1 editorial group
- Done
- Arpad to write a new revision of BIRD 117 and 118 to generalize references
to parameters in files (.ami or any)
- in progress
- Ambrish update BIRD 145 for pad to pin mapping and other clarifications
- Need to say what it will not solve
- in progress
-------------
New Discussion:
Arpad: We need to know if [External Model] allows additional nodes
BIRD 144:
- Ambrish: Feras could not make it today, would prefer to defer
- Arpad: The complexity of this originally simple proposal is growing
- The value is becoming questionable
- Ambrish: This could be discussed by email
- Walter: Does BIRD 144 add something beyond what ISS has?
- Ambrish: It eliminates the need for the ISS subcircuit
- Some cases might be handled by direct association
BIRD 145:
- Arpad: We spent a whole meeting on this
- Walter: The idea is to model all on-die circuits between a single buffer
[Model] and pad?
- A bank of 96 SerDes buffers can share the same power circuit
- Ambrish: We should discuss this by email
- James: We concluded that 5.0 already allows using [External Circuit] for
power dist
- Page 136 has an example circuit with a PDN
- There are some pin mapping issues, but BIRD 145 does not resolve that
- The diagram shows 2 buffers connected to 1 circuit, there could be more
- Arpad: Agree, this BIRD introduces cascading models
- Tools may have trouble telling which model in the circuit goes to a certain
pin
- Walter: A package model can model a slice of the package
- You have a similar problem there too
- Arpad: That is a more general problem that BIRD 145 need not address
Arpad showed "The AMI analog model" from 25 Jan 2011:
- Arpad: Are the isolation amplifiers needed?
- Input signals are often from ideal sources anyway
- Output signals usually have no load
- Scott McMorrow had insisted on these
- No recent supporting arguments
- Walter: These are not needed
- Mike: We should state that input sources and output loads must be ideal
- Bob: The language could be made technically equivalent to the amplifiers
- Walter: The simulator can add them only where needed
- James: Something needs to terminate the left side block
- Terry drew a circuit with a current driver and 50 ohm load
- That is not backward isolated
- Arpad: The EDA tool can figure this out
- James: The question is what information to give the tool
- Radek: This goes back to AMI methodology
- The analog part is a single transfer function
- We need a non-ideal source with a certain impedance
- It can be communicated in the spec
- Arpad: It could be included in an ISS subcircuit
- Once a non-ideal source is specified you can't override it
- Bob: Is the outlined box the s-param itself?
- Radek: That could be other circuit types
- Walter: If termination is needed it will be in the ISS subcircuit
- Arpad: They can add linear gain elements too
- James: Why have the unity gain amp then?
- Arpad: To assure that there are no boundary condition requirements
- James: A real IC could not have that
- The signals on the left are AMI_Getwave output?
- Walter: Yes
- Radek: The amplifier after an ideal source adds no value
- Bob: An s-param might have some input impedance
- We can't leave it for the tool to calculate
- Walter: It is the responsibility of the model maker to specify the input
- James: It will be difficult to model Terry's circuit
- Walter: The unity gain amplifier can be in the subcircuit
- James: Can ISS model amplifiers with arbitrary impedance?
- Walter: Yes
- Arpad: Thevenin equivalents are easy
- James: IBIS has not specified that
- Arpad: We decided in Jan to have no analog model between Getwave and
convolution
- James: The flow shows Getwave connected to the analog model
- Arpad: That is the impulse response
- Walter: Engineers will come to the conclusion that it can be done that way
- James: Why show the signals being input to the ISS block?
- Arpad: We can take out these amplifiers and define the inputs and outputs
- Bob: You don't know if you need the amplifier or not
- James: Model makers will know when to put it in
- The spec just needs to have everything that might be needed
- Bob: An s-param block might not be interchangeable with an RC block
- That needs to be spelled out
- James: There is a question whether or not that needs to be spelled out
- Bob: I will send a mathematical discussion to the group
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Next meeting: 27 Mar 2012 12:00pm PT
Next agenda:
1) Task list item discussions
-------------
IBIS Interconnect SPICE Wish List:
1) Simulator directives
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