================================================================================ IBIS INTERCONNECT TASK GROUP Mailing list: ibis-interconnect@freelists.org ================================================================================ Attendees from February 22, 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* Randy Wolff* Siemens EDA Arpad Muranyi* ST Microelectronics Aurora Sanna Teraspeed Labs Bob Ross* University of Illinois Jose Schutt-Aine Zuken USA Lance Wang* Michael Mirmak convened the meeting. No patents were declared. Justin Butterfield took minutes. Review of Minutes: - Michael called for review of the minutes from the February 15, 2023 meeting. Michael displayed the minutes. Arpad Muranyi moved to approve the minutes. Bob Ross seconded. The minutes were approved without objection. Review of ARs: - Arpad Muranyi to give an example of the physical connectivity needed for EMD automation [AR]. - Arpad suggested to keep this open. - Michael to check with Synopsys on permission for using the W-element S-parameter feature and what they can share on the algorithm details and model restrictions [AR]. - Michael has reached out to Ted Mido to ask details on the algorithm and features required for accuracy. He has invited Ted to this meeting and is waiting for a reply. He suggested to keep this open. - Michael to look for the original Touchstone manual. - Michael reported Touchstone was the software and the files were called the Touchstone file format. He did find an HP 8753D Network Analyzer manual which discusses the "S2P" file formating. A more recent RF Network Analyzer (HP E5070B) manual does mention other Touchstone formats such as "S1P", "S3P", and "S4P". Walter Katz asked if there was any mention of Noise data. Michael replied he has not seen Noise data. Arpad asked if we can place the documents on the IBIS page. Michael will check with Keysight [AR]. Bob asked if there was any limit to the number of ports. Michael asked if Bob could find this information. Bob noted it is was mentioned in one of his IBIS Summit presentation, but he is not sure where this came from. Walter noted one difference between Touchstone 1 and Touchstone 2 is that Noise data is normalized in Touchstone 2. He would like to have a discussion if Noise data makes sense in a file with per port references. Walter noted there are complications for non-interconnect devices. Arpad will ask Vladimir his thoughts on this. Michael will add Noise data discussion to the bin list as a future discussion topic. - Michael to ask if there is any need from Walter to support Touchstone 1 files with port mapping. - Michael reported this is done. Opens: - Michael noted the major discussion topic is how to integrate Touchstone 1 with Touchstone 3 and new features, such as port mapping. Discussion: Touchstone 3.0 Direction: Michael noted, in the past, Walter had stated the industry has not adopted Touchstone 2, and we would like to have a discussion on why. Walter commented that he always objected to Touchstone 2. He suggested the only reason we needed Touchstone 2 was to add the impedance per port for rail nets. We added additional features, and he has not seen these features widely used. Walter suggested to have a Touchstone 1.1 with per port impedance. He noted the other important features are port information in a machine readable format, and how to enable smaller files sizes. Walter's preference would be to take Touchstone 1 add per port impedance, port naming, and sparse matrix. Arpad asked if parsers would need to be changed. Walter replied, if you add per port impedance, parsers will have to change. The port naming could be carefully constructed comments. And, the sparse matrix would have to be converted back to the original format. Arpad asked why not just continue with the keyword approach. Walter was concerned users would not upgrade to the new format if there is not a need to use the new features. Bob asked if Randy Wolff has shipped Touchstone 2 files. Randy replied Micron has provided Touchstone 2 files for the per port impedance and to reduce the file size with the upper or lower matrix. Arpad asked if there were customers that could not use the Touchstone 2 files. Randy reported that there have been cases where customers could not use the Touchstone 2 files without down converting. Michael stated that we have a proposal to encapsulate the Touchstone 1 data either in-line in the file or as a file pointer to the raw data. The Touchstone 3 file would be a wrapper. Michael asked if either of these options would be a good solution. Walter noted this would not work for per port impedance, since the data will change. Arpad commented the purpose of the wrapper file would be for pole-residue and port mapping. Walter stated we could work out the formatting and add port naming as standardized comments. Arpad asked if it makes sense to have the comments, which are there already. Walter stated their solution is to have a separate file for the port naming information. Michael asked, given that Touchstone 1 is limited, is it worth it to only add the port naming feature. Walter asked if impedance per port is the only feature necessary to solve today's problems. Arpad noted there was ambiguity in the Touchstone 1 specification. Walter asked if there is any other feature in Touchstone 2 that users must have to solve today's problems. Randy noted that file size reduction is very helpful. Walter agreed with the usefulness of file size reduction. Michael noted we are looking at a Touchstone 3 without all the Touchstone 2 features. Walter suggested we should not continue with Touchstone 2 and introduce a new Touchstone X format. Michael gave an AR to everyone to think about what assurances we have that Touchstone X will be adopted by the industry [AR]. Randy moved to adjourn. Bob seconded. Next Meeting: The next meeting will be March 1, 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)