================================================================================ IBIS INTERCONNECT TASK GROUP Mailing list: ibis-interconnect@freelists.org ================================================================================ Attendees from December 6, 2023 Meeting (* means attended at least using audio) ANSYS Curtis Clark Broadcom James Church Intel Corp. Michael Mirmak* Michael Brownell Keysight Technologies Ming Yan Marvell Steve Parker MathWorks Walter Katz* Micron Technology Justin Butterfield Siemens EDA Weston Beal, Arpad Muranyi*, Randy Wolff* ST Microelectronics Aurora Sanna Teraspeed Labs Bob Ross* University of Illinois Jose Schutt-Aine Zuken USA Lance Wang* Michael Mirmak convened the meeting and took minutes. No patents were declared. During the minutes review, Arpad Muranyi moved to approve the November 15 minutes with a correction to the following sentence: "In addition, he expected Pete, Steve - still open" Michael stated that this was an incomplete summary of two outstanding items: an update to the Interconnect web pages by Steve Parker and a report on the S-parameter compression algorithm from Pete Pupalaikis. Bob Ross seconded approving the minutes with this expansion. There were no objections and the minutes were approved. The team also reviewed the minutes of the November 29 meeting. Arpad noted several changes he requested through the e-mail reflector: 1) A missing word “in” in the following phrase: “inclusion in a separate revision” 2) Please change: “Arpad noted that yellow highlights in the document show minor changes/updates.” to: “Arpad noted that yellow highlights in the document indicate the most recent changes/updates.” Arpad moved to approve the minutes with these changes; Bob seconded. There were no objections and the minutes were approved. During the AR review, Bob outlined his findings related to the equations in the Touchstone pole-residue proposal document. He suggested that the document can continue with its current formatting, but one format was shown in Jose Schutt-Aine's presentation on vector fitting in a recent summit where the numerator and denominator had the same formatting. Vector-fitting involves toggling between them. The professor's format exists in current textbooks. He additionally suggested inclusion of pole-zero-to-Foster-to-PLS format conversion information with emphasis on the fact that this uses an IBIS-ISS format. Michael noted that his AR to provide restructuring suggestions offline was closed, as this information was sent to the reflector. Randy Wolff asked to keep his AR regarding the known-issues document open. All other ARs were closed or completed. Arpad reviewed the current pole-residue format proposal. He noted that he is maintaining the use of capital letters A and B for readability. Michael commented that his own research showed no convention on this issue. Arpad also noted that adding a File_revision subparameter was also proposed. In addition, the team needs to revisit italic formatting. In the current draft, the phrase "Such items shall be combined..." was pointed out by Randy and Weston Beal as unclear. Bob noted that this operation should be performed by the EDA tool (extraction/fitting, not extractor as pointed out by Arpad). Randy replied that the issue is that the sentence is not clear at all; the problem is unrelated to the duplicate-pole rule. Arpad added that duplicate poles can appear in real life but are not supported here. Bob replied that duplicate poles are not supported by vector fitting algorithms. Further, Jose Schutt-Aine says manually adjusting the data to be nearly identical is the practice. Walter Katz asked whether it is common knowledge that duplicate poles are bad. If so, we should just prohibit them without further explanation. Randy added that he has seen this issue in pole-zero data before. Bob stated that he has seen presentations using duplicate data in European summits. Randy noted that this will have to be checked in the parser. Bob asked about signs and sign conventions in the data. Arpad showed the latest information he has from Vladimir Dmitriev-Zdorov on Foster format vs. what Siemens EDS actually uses/recommends for Touchstone. These are equivalent but there are five reasons why PLS has advantages over Foster as a format. Arpad advocates not including this information in the specification itself but posting it as background separately. Michael agreed, for PLS-to-Foster format conversion. Bob asked whether the Foster format mentioned here the IBIS-ISS Foster format. Randy noted that he wanted to ensure there was an explanation of conversion available. Walter asked whether IBIS-ISS supports Foster but whether Touchstone 3.0 would not. This could be embarrassing. Michael asked about the burden of supporting both. Walter suggested that the team members ask knowledgeable internal colleagues about preferences and whether they agree on the format advantages of pole-residue over Foster. Arpad replied that IBIS-ISS is standardizing the Synopsys version of HSPICE's passive elements per their donation, and that includes a library of controlled sources, one of which is Foster. There could be a compatibility issue if other formats are adopted. Walter asked whether, if you get a PLS data set, if it can be used in other commercial tools. Randy replied that every EDA tool has some fitting format or algorithm. We need to show format equivalence. Arpad added that all tools can accept S-parameters and perform independent fitting of the data. Walter proposed sending out the pole-residue analysis document to a wider audience for review; the PDF was included in the reflector e-mail. Michael accepted the AR to send the e-mail attachment to the reflector with a different cover letter and questions asking for review. [AR] Bob added that our decision may impact data and formatting in the numerator coefficient (the equations would change). Arpad moved to adjourn the meeting; Bob seconded. The meeting adjourned. The next meeting will take place on December 13, 2023. ================================================================================ Bin List: 1) [Complete draft Touchstone document separating version 1.0 and 2.0 into their own chapters] - REMOVED 2) Create structures to encapsulate Touchstone 1.0 data in Touchstone 2+ specifications - TABLED 3) Complete draft Touchstone 2.0 document containing TSIRD3 and TSIRD4 draft (Muranyi) – COMPLETED IN DRAFT 10 4) Complete pole-residue format BIRD draft (Muranyi) 5) Complete port naming proposal (Katz) 6) Create alternatives to the Touchstone 1.0 option line before the "R" character - TABLED 7) Complete ISS-IRD 1 Draft - Enable Cascading of S-parameters Through W-element (Mirmak) - TABLED 8) Complete/revise Touchstone 3.0 draft outline (Mirmak) – dependent on several items above Tabled ARs: - Arpad to give an example of the physical connectivity needed for EMD automation.