================================================================================ IBIS INTERCONNECT TASK GROUP https://urldefense.proofpoint.com/v2/url?u=http-3A__www.ibis.org_interconnect-5Fwip_&d=DwIGAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=DcQR-qLpQg5lIreuM6-NYECRIAFXt268PRNS5WO043M&m=shdzGd1TwO7ysVmNzVS5KHtMWTmHrx_EE8yYeTotYm-igtIMbKKO4Dy0hzeLi364&s=rdcQZc4qZVw9A_2J3nzxSLalv_k2agTqxX-rh2HUHpM&e= Mailing list: ibis-interconnect@freelists.org Archives at https://urldefense.proofpoint.com/v2/url?u=http-3A__www.freelists.org_archive_ibis-2Dinterconn_&d=DwIGAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=DcQR-qLpQg5lIreuM6-NYECRIAFXt268PRNS5WO043M&m=shdzGd1TwO7ysVmNzVS5KHtMWTmHrx_EE8yYeTotYm-igtIMbKKO4Dy0hzeLi364&s=aHDDEHFbXA5A4DnfD2CVL4WaawdHuZPbT5yo_Eq1_gI&e= ================================================================================ Attendees from January 26, 2022 Meeting (* means attended at least using audio) ANSYS Curtis Clark Intel Corp. Michael Mirmak* 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 Professor Jose Schutt-Aine from the University of Illinois introduced himself. His current research is on algorithms for signal integrity simulation and modeling. 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 January 19, 2022 meeting. Michael displayed the minutes. Randy Wolff moved to approve the minutes. Arpad Muranyi seconded. The minutes were approved without objection. Review of ARs: - Arpad to ask Vladimir if it is possible to reduce ports in the pole-zero format. - Arpad reported, from his discussion with Vladimir, it is possible to reduce ports in a pole-zero format. - Everyone to provide their requirements for the pole-zero format. - Michael reported this is the topic for today's discussion. Opens: - Walter Katz sent out an email about the format of the network data, and he thought there could be an issue with the specification. - Walter asked if we have reviewed the survey. Michael replied that we did briefly discuss it, and he sent out the link to the survey results. We can add this to bin list. Pole-Zero Discussion: Jose shared a presentation on interconnect modeling using model order reduction. Since the interconnect circuit model is linear, model order reduction can be done to reduce the complexity of the frequency dependent system model. The model form can be a rational function that can be used in SPICE. Jose gave an overview of the process going from S-parameters to SPICE simulation. He presented the flow of model order reduction with vector fitting. He showed the flow for passivity enforcement with the Hamiltonian Matrix. The goal is to generate a circuit netlist which is modeled as an admittance calculated from the S-parameter. He compared simulation results from the recursive convolution method and the pole/zero SPICE model, which showed good agreement between the simulation methods. Jose noted the algorithm may come up with negative circuit element values. But, his team developed an approach to add dependent sources to keep the circuit elements positive. Arpad asked if causality can be a problem. Jose replied, when you find a solution for the rational function, it will be causal. The passivity enforcement is more computationally intensive due to the size of the matrix and number of eigenvalues. Michael stated we are considering a pole-zero format as a way to convey the same information as a Touchstone model. If we were to use the pole-zero format, would the pole-zero data be the only data required, or would we need additional information? Jose replied getting to the pole-zero values is not easy, while the S-parameters are straightforward for field solvers and VNAs to measure. Arpad stated the motivation is to reduce the size of the model format, and the idea was to standardize the pole-zero format. Jose agreed the pole-zero format would be a much smaller format. Michael commented we have the opportunity to update Touchstone. For Touchstone 3, one of the feedback items was to reduce the size, and pole-zero format is attractive for that. Michael asked if there is any additional information needed to ensure a quality model and the circuit synthesis is correct. Jose replied you need to take care of the model order reduction and passivity enforcement. Michael noted IBIS does not describe how the data should be created and extracted. Jose stated you would only need the constant term, poles, and zeros, as complex numbers. You would also want to specify the order of the model, and you may want to state whether the passivity has been enforced. Bob Ross asked about support for active S-parameters. Jose replied, for active systems, the stability depends on the load and is not guaranteed. Bob asked if there are strategies for zeroing out "Sij" cross terms that are not significant. Jose replied this exercise does not address this, and this would be better to address at the S-parameter level. This is a judgment if the term is important or not. Next Meeting: The next meeting will be February 2. ================================================================================ Bin List: 1. Touchstone 3 2. Pole-zero support for Touchstone 3. New version of Touchstone to include 3 TSIRDs 4. Clarification BIRD drafts from ATM 5. Review Touchstone survey results