IBIS Macromodel Task Group Meeting date: 18 January 2011 Members (asterisk for those attending): Agilent: * Fangyi Rao Radek Biernacki Ansoft: Chris Herrick Danil Kirsanov Ansys: * Samuel Mertens * Dan Dvorjak Deepak Ramaswamy Jianhua Gu Cadence Design Systems: Terry Jernberg * Ambrish Varma Celsionix: Kellee Crisafulli Cisco Systems: * Mike LaBonte Stephen Scearce Ashwin Vasudevan Ericsson: Anders Ekholm IBM: Greg Edlund Intel: Michael Mirmak LSI Logic: Wenyi Jin Mentor Graphics: * John Angulo Vladimir Dmitriev-Zdorov Zhen Mu * Arpad Muranyi Micron Technology: Randy Wolff Nokia-Siemens Networks: Eckhard Lenski Sigrity: Brad Brim Kumar Keshavan Ken Willis SiSoft: * Walter Katz Mike Steinberger Todd Westerhoff 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 ------------- Review of ARs: - Arpad: Update Typos BIRD draft - In progress ------------- New Discussion: Arpad showed the update Typos BIRD: - Arpad: Ambrish brought up a leaf/parameter naming problem - The definitions of parameter and branch are adjusted - Fangyi: What if two parameters have the same reserved name - Arpad: They will be unique because they are contained in different branches - It says "each sub-branch of A BRANCH" - Maybe it could be worded better - Arpad: DLL data passing more explicitly described now - Everything In/InOut in the AMI file must be passed to the DLL - Everything Out/InOut in the AMI file must be passed out of the DLL - Bob: We should note that Table is yet to be resolved - Not all rules apply to tables - Arpad added new language for this - Arpad motioned to vote on submitting this BIRD with today's changes - Mike LaBonte seconded the motion - Roll call votes: Agilent: Y Ansys: Y Cadence: Y Cisco Systems: Y Mentor Graphics: Y SiSoft: Y Teraspeed Consulting Group: Y Texas Instruments: Y - The voted passed AR: Arpad submit Typos BIRD to IBIS Open Forum Arpad showed slide 4 of the analog model boundary definition presentation - Arpad: Do we need to mention these two usage models? - If the PWL sources are not part of the model that must be spelled out - We need to spell out how the TX GetWave output would be used - Where is the inverter? - Fangyi: Usually a voltage change triggers a rise or fall edge - Only the trigger threshold is relevant - Using TX GetWave as input breaks the model - The voltage can be anything - Arpad: The TX GetWave source is connect by an isolation amplifier - Fangyi: And this is part of the analog model - Ambrish: What has really changed between 5.0 and this? - Arpad: 5.0 said nothing about how to generate the impulse response - Scott: The boundary is defined as an infinite isolation boundary - Anything not isolated must be placed in the analog side - It would be nice to put all analog stuff in the TX analog side - That becomes unwieldly - We can't model it as a trigger unless it is only doing convolution - IBIS assumes all analog effects are in the analog model - We must allow continuous time EQ to be on the other side - Walter: Excellent explanation - Matlab implemented a C routine - Vendors use analog models in their internal tools - Opal has template models - We might want AMI-ISS models instead of External Model - John: These 2 models differ - The 2nd does not use the impulse response - Does this have consequences - Arpad: That is my understanding - Walter: The same model used in the picture below will give the same results - Arpad: The top and bottom have different impulse response flow - Walter: It's LTI so you can change the order of operations - AMI requires impulse response for TX input - John: Do we need to use the bottom method instead of the top? - Walter: It's just to say AMI models don't have triggered inputs - Arpad: in BIRD 122 the ideal sources would have to be redefined for the bottom - This was in the BIRD 122 drawings - This problem is not just with this BIRD - Scott: If TX is created with s-param, isolation amps must be in the model - This is the only way to ignore reflections from the algorithmic side - A template circuit should show the VCVS for both TX and RX - Bob: If TX has a 1ns driver where in the s-param does 1ns show up? - What is needed to capture it in an RC circuit - Scott: Opal broke the usage model by moving rise time to the PWL - The model builder should determine if the time is internal or external - Ambrish: AMI was supposed to have all analog outside - Scott: It is a practical issue - A CTLE with multiple settings might have to create 16 models - This allows us to have less analog models - Walter: Sometimes 128 analog models, it can be unwieldly - One model with multiple parameters makes it easier - It can be more accurate this way - Arpad: We agree that the analog portion can be s-param + isolation amp - Walter: Scott said the isolation E element would be in the s-param - Scott: Otherwise you have to define the s-param interface - We cut the driver at the output transistors - Bob: The isolation is at the S11 boundary - We have an S12 term but not S22 - Arpad: I thought Scott wanted an E element in there - Scott: The E element must be in the s-param - The s-param must have an isolation boundary - The input impedance must be either zero or infinite - If zero nothing can ever drive it - Infinite impedance is an isolation amp - Bob: An RC circuit needs an isolation amp - The s-param already has it - Arpad: Can we put the PWL sources back in? - An s-param can exactly duplicate an RC circuit - Walter: The intent was to address how IC vendors are doing it - Bob: Would TI produce an s-param models that includes driver rise time? - Alfred: We can do that - Bob: DO they state what rise time to use? - Walter: Opal recommends putting it all in the s-param - But vendors can do otherwise - Alfred: We can provide a single S4P for TX - Arpad: So voltage sources are needed only for RC circuits? - Walter: The vendor specifies - Alfred: Does the tool need to do different things? - Walter: Yes, it is different if there is an s-param - Bob: This should be in the BIRD ------------- Next meeting: 25 Jan 2011 12:00pm PT Next agenda: 1) BIRD 121-124 discussions ------------- IBIS Interconnect SPICE Wish List: 1) Simulator directives