IBIS Advanced Technology Modeling (ATM) Task Group Meeting date: 29 May 2018 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 Mentor, A Siemens Business: John Angulo * Arpad Muranyi Micron Technology: * Randy Wolff * Justin Butterfield SiSoft: * Walter Katz Todd Westerhoff 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. Justin Butterfield took the minutes. -------------------------------------------------------------------------------- Opens: - None. ------------- Review of ARs: - None. -------------------------- Call for patent disclosure: - None. ------------------------- Review of Meeting Minutes: Arpad asked for any comments or corrections to the minutes of the May 22 meeting. Justin moved to approve the minutes. Bob seconded the motion. There were no objections. ------------- New Discussion: - Discussion: Allow Terminator as a Model_type for IBIS-AMI receivers Michael Mirmak stated he had heard that the group was leaning toward his solution #1, which was to simply remove the AMI restriction on the Terminator Model_type. He commented that this would be a very easy BIRD to draft. Arpad commented that Figure 11 in IBIS 6.1 shows the Rac and Cac connecting to the node 0 symbol. If someone wants to use these in a power aware simulation, they would not be very useful. Arpad commented that if we only use these features for AMI simulations with ideal power, we could go with solution #1. But, we would need more edits to the IBIS Specification to make them suitable for power aware simulations. He has heard of some EDA tools discussing support for power aware simulation with AMI. Walter stated he would like to review the three options Michael had presented. Michael shared his slides with the 3 options: 1. Remove the prohibition on Model_type Terminator for IBIS-AMI. 2. Permit [Rac], [Cac], [Rgnd] and [Rpower] in the other Model_types. 3. Create New Model_type that only uses [Rac], etc. Arpad noted that Walter had also suggested to put these parameters in the AMI file. Walter stated he would limit these to Input models, allowing those keywords for Input models only. Walter commented on the Figure 11, what we want is to not have the clamp curves, and these are not required for Inputs. He thought we could just add the Rgnd and Rpower to the Input model. Radek stated that it would be okay to put in these keywords for the Input model, but the option #1 is easier. He suggested that the ground in Figure 11 is a separate issue that we do not need to resolve now. Walter stated on page 31 of IBIS 6.1 there is a description of the Model_types including Terminator. He thought that it would be easier and more logical to change the Input, then we would not need to scrub the IBIS Specification to clarify Terminator. Arpad suggested that we should add Rac_pullup, Rac_power_clamp, Cac_pullup, Cac_power_clamp, etc. keywords. Walter clarified that we do not have the Pullup and Pulldown versions for Input Model_types. Arpad agreed. Michael commented that this could also be applied to single-ended models and asked if this would make things more complicated for the new C_comp model. Randy stated you could also do this inside the IBIS-ISS subcircuit for C_comp. Arpad agreed and stated we can also do this with External Model. Walter asked if these would override or replace the Ground Clamp and Power Clamp or if they should be in parallel. Bob suggested that they should be in parallel. Michael stated the difficulty is that we want the true diode clamps to be there, but it is more difficult to measure the curves independently. Bob stated this is an extraction problem, and there are multiple solutions that work. Arpad noted that you cannot represent the diode clamps with a resistor. Michael asked if we should write up a BIRD for a modified version of option #2. Arpad suggested to also add the Rac_powerclamp, Rac_gndclamp, Cac_powerclamp, and Cac_gndclamp. Michael asked if we should make new keywords or subparameters. Bob replied we should make them new keywords. Michael asked about support for the I/O Model_type. Walter suggested to restrict it to Input only. Walter asked if Rgnd and Rpower can be represented in the clamp curves. Michael stated, yes, that the purpose is to simplify the models. Walter asked if we need Rac and Cac support for Michael's purposes. Michael replied that he has not seen these in differential algorithmic models. Walter stated these could cause problems for drivers and C_comp compensation. Arpad asked if Rac and Cac are not a high importance and if we can wait for Randy's C_comp BIRD for these. Michael stated he would be okay with this. Bob stated that we should still have the clamp tables in parallel, and for I/Os things are more complicated. Arpad asked for outputs how the Rgnd and Rpower would toggle with the buffer state or if they would be there all the time. He asked if Walter was intending to include these on the driver. Walter stated if you have Rgnd or Rpower would only replace the clamps. Bob commented for Submodels there could some complications with the different modes. Arpad asked if these keywords are available for Submodels. Michael noted that the are currently not. But, he agreed that it could be a problem if we allow support for I/Os. Bob suggested to limit these keywords to Inputs and Terminators. Arpad asked if we could add Rgnd and Rpower to Terminators and Inputs and if this would work for Michael's needs. Michael replied that this would work. Bob asked why not Rac and Cac. Michael noted that these might not be that useful for differential drivers and Randy's C_comp should address this. Radek noted that he still prefers to allow the Terminator for AMI, as the thresholds are not that useful. Arpad stated that he prefers to allow for Rgnd and Rpower the Input. Radek thought we could do both. Bob was concerned we should not allow thresholds for Terminators. Michael noted that this is illegal. Michael took an AR to prepare a draft BIRD allowing Rgnd and Rpower for the Input Model_type. Bob commented he does still have concern with not including split versions of the Rac and Cac. - Discussion: BIRD194 Comments Arpad asked about Michael's BIRD194 comments and if we need to keep it on the Agenda. Michael replied that if people have comments to please send them out to the reflector, but he does not see a need to keep this topic on the agenda. AR: Michael to prepare a draft BIRD allowing Rgnd and Rpower for the Input Model_type. -------------------------- Motion to Adjourn: Randy moved to adjourn. Michael seconded the motion. Arpad thanked everyone for joining. ------------- Next meeting: 5 June 2018 12:00pm PT ------------- IBIS Interconnect SPICE Wish List: 1) Simulator directives