================================================================================ IBIS INTERCONNECT TASK GROUP Mailing list: ibis-interconnect@freelists.org ================================================================================ Attendees from April 12, 2023 Meeting (* means attended at least using audio) ANSYS Curtis Clark Intel Corp. Michael Mirmak* Michael Brownell Keysight Technologies Ming Yan Marvell Steve Parker MathWorks Walter Katz Micron Technology Justin Butterfield Siemens EDA Arpad Muranyi*, Randy Wolff* ST Microelectronics Aurora Sanna Teraspeed Labs Bob Ross* University of Illinois Jose Schutt-Aine Zuken USA Lance Wang* Michael Mirmak called the meeting order and took minutes. Randy Wolff was officially associated with with Siemens EDA. No patents were declared. Michael called for review of the mintues from the April 5, 2023 meeting. Michael displayed the minutes and noted a misspelling of "mintues". He also noted that Arpad Muranyi found a bad date for the next meeting. Arpad moved to approve the minutes with corrections; Randy seconded. The minutes were approved without objections. Review of ARs: - Michael to check if the Network Analyzer manuals documenting the original Touchstone can be posted to the IBIS website [AR]. Michael had completed his review of the documents provided by Keysight Technologies, and forwarded them and an associated agreement to the IBIS Open Forum board for posting. Randy took the AR to place posting the documents on the Open Forum agenda. [AR] Bob Ross observed that these are merely historical references and should not be considered critical to the current discussion. The essential question is what features should be considered part of the official Touchstone format versus a proprietary version of the format. Michael noted that the historial references provide guidance on what the oldest tools and parsers would have written and read, and therefore define the maximally compatible format. In the absence of an official Touchstone 1.0 document, we don't even know what parts of Touchstone 1.1 were improvements when compared to existing practice. Michael agreed to contact Stephen Peters [AR] regarding whether a copy of the Touchstone 1.0 document is avaiable, plus any background historyical data. Bob observed that, ultimately, we don't care what the original formats were, as we have an official version of 1.0 as part of the 2.0 document. Arpad clarified that our only question is whether *our* 1.0 portion of the 2.0 specification violates old parsers. Bob replied that there are possibly proprietary variations, but we ultimately don't care about them. Arpad asked for confirmation that our intent is to keep old parsers working. To finish AR review, Arpad observed that he completed his draft update AR. Michael noted that the document would be reviewed later in the meeting. During Opens, Michael mentioned that he had sent to the reflector a small portion of the EEsof ANACAT Reference Manual describing 1- and 2-port Touchstone formatted data files. Arpad wanted to know about ABCD naming; Michael gave a brief overview, and suggested he could send out a more detailed description later. Arpad reviewed the changes in his draft. This updated version supports "R " or "R ", etc. with only as many values as ports; no other combinations are permitted. Some rewording is still needed to explain new R reference values and their use. Randy mentioned that we wouldn't break proprietary parsers if we are more restrictive than what we know of extant proprietary formats. Michael asked for clarification: in this case, Touchstone 1.2 "stuff" would work in a proprietary tool, but proprietary "stuff" won't work in TS 1.2 parser. Randy agreed. Bob suggested that the green text that refers in the draft to "with editorial changes only" is ambiguous. This release would be 2.1 and designated 2.1. Randy suggested that this part of the document is not the right place to legislate what gets included Bob added that we have some syntax possibilities in 2.0 that would be captured in a 2.1 document. Randy clarified that the editorial description sets a strategic direction but should not be a requirement. Arpad replied that the BIRD's intent is to relax the 1.0 strict reference impedance rules. This is now a logical exercise. referring to Touchstone 2.1. Randy asked whether we could have a Touchstone 2.1 file that has the relaxed option line with multiple references. Arpad replied that Touchstone 2.0 embraces 1.0 syntax only. Michael suggested, per recent reflector discussions, that there are two approaches: allow a "relaxed" Touchstone 2.1, where all keywords (including [Version]) become optional, or define a Touchstone 1.2, where the only change from Touchstone 1.0/1.1 is the expansion of the reference impedance option line. Arpad noted that wordsmithing the new document for this will be burdensome . Randy added that the Touchstone separaration document also hasn't been looked at for a while. Bob stated that the [Version] keyword tracks wtih the document number, even if there is no change in syntax. This is similar to IBIS. We have something different with this document: versions are embedded (implied) before [Version] 2.1. These changes will be in a 2.1 document; version 2.1 has to be a permitted number. [Version] 2.1 is therefore required. Arpad suggested that the option definition in 2.1 would still be "active" for # line with multiple R values. Randy added that an expanded Touchstone 1.0-style option line with multiple R values would be easy for a parser to recognize, in the absence of Touchstone 2.1 features and keywords. Bob stated that it's a false assumption that [Version] keyword is required. The team agreed that a Touchstone 2.1 document could be written that allows the expanded option line without forcing [Version] or other keywords into otherwise Touchstone 1.0-compliant syntax. [AR] Arpad took the AR to create a draft 3 and distribute it to the reflector. The team will take up this and the separation document next time, assuming agreement is maintained on the direction in draft 3. Randy moved to adjourn. Arpad seconded. The meeting adjourned. Next Meeting: The next meeting will be April 19, 2023. ================================================================================ Bin List: 1. Draft Touchstone document separating version 1.0 and 2.0 2. Encapsulating Touchstone 1.0 data 3. Touchstone 2.0 draft with TSIRD3 and TSIRD4 4. Pole-residue format 5. Port naming 6. Alternatives to the Touchstone 1.0 option line 7. Enable Cascading of S-parameters Through W-element 8. Touchstone 3.0 draft outline (dependent on several items above) Tabled ARs: - Arpad to give an example of the physical connectivity needed for EMD automation.