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Compact model standardization – a GNU perspective

Compact model standardization – a GNU perspective. Paolo Nenzi - CNR-INFM Wladek Grabinski - GMC. Standard. What a standard is ?

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Compact model standardization – a GNU perspective

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  1. Compact model standardization – a GNU perspective Paolo Nenzi - CNR-INFM Wladek Grabinski - GMC 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  2. Standard • What a standard is ? • a documented agreement containing technical specifications or other precise criteria to be used consistently as rules, guidelines, or definitions of characteristics, to ensure that materials, products, processes, and services are fit for their purpose. 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  3. Actual: The standard is the compact model. Not all candidates for a given technology are standardized. GNU: The standard specifies the rules to develop compact models. The standard must be open. The compact model must be free. Perspectives 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  4. Actual perspective The models are standards. First class models (BSIM, PSP) and second class models. Long delays in model release in circuit simulators. Lack of models for new or less common devices. GNU perspective Models conform to an open standard. All models are equals. Faster development and acceptance. Development of model for frontier devices (MEMS, etc.) Consequences 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  5. An Open Standard • The GNU compact model standard should be open (as defined by OSI): • No intentional secrets. • Availability (publicly available, royalty-free). • Based on royalty free patents. • No agreements (NDAs, etc.) to deploy conforming implementations. • No dependencies on non open technology (according to this definitions) 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  6. A free model • The compact models should give the 4 freedoms: • The freedom to run the model, for any purpose. • The freedom to study how the model works, and adapt it to your needs. • The freedom to redistribute copies so you can help your neighbor. • The freedom to improve the model, and release the improvements to the public, so that the whole community benefits. 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  7. Key points of the standard • What should be standardized: • How model equations are formulated. • How model is coded. • How model is implemented into simulators. • A benchmarking procedure and the benchmarks required to validate the model. • How to extract parameters and verify libraries. 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  8. A GNU Compact Model DevKit • The open standard should lead to a free compact model development kit. • The DevKit will be an integrated suite of tools that will interface with the parametric measurement instrumentation on one end and with circuit simulators on the other. • The DevKit will integrate into IC-CAD flows to evaluate models on real circuits. 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  9. A GNU Compact Model DevKit • The bottleneck today is the implementation of compact models into circuit simulators. • CM-DevKit must allow for easily integration of the models into each simulator’s compiled model interface (compliant approach). • CM-DevKit must be able to process measured data to generate parameters sets. 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  10. The CM DevKit – key tools • A compact model capture tool (to generate a Verilog-A or VHDL-AMS description of the model). • A compact model analyzer/synthesizer (to generate an intermediate form). • A set of intermediate form languages compiler and interpreters to assist in model development, playback and debug. • Circuit simulators to evaluate the model (both free and commercial). • A parameter extraction tool. 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  11. Existing tools: gEDA is an extensible schematic capture tool able to generate spice netlist from schematics. Paragon (?) Open Issue: There is no gEDA verilog-A or VHDL-AMS extension. There is no capture environment specifically targeted to CM development. The CM DevKit – Model Capture 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  12. Existing tools: ADMS (Laurent - Freescale). This tool generate codes that can be compiled into simulators using their CM extensions. Generated code runs almost at the same speed of human written code. Open Issues: ADMS is under development. ADMS translation script writing is poorly documented. The CM DevKit – Model synthesizer 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  13. Languages Tcl/Tk Python C / C++ Open Issues: None!Tcl/Tk and Python are already used in CAD flows and most of the simulators provide a C/C++ API for CM integration. The CM DevKit – Intermediate languages 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  14. Existing tools: fREEDA GNUcap Ngspice QUCS Open Issues: Input language compatibility. Common set of analyses. Common set of modeling API. Common data output format. The CM DevKit - Simulators 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  15. The CM DevKit – Simulators • The ADMS approach of translating the model description into each simulator’s API is winning as does not require any intervention on the simulator itself. • Faster development time, no more implementation bottleneck. 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  16. Existing tools: None!Octave (free Matlab-like software) should be used to process IC-CAP .mdm data. Open Issues: Need to write an extraction tool based on a standard “measurement language” that can interface to IC-CAP data server. Writing a parser for .mdm files. The CM DevKit - Extraction 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  17. Benefits of the GNU perspective • No discrimination between models and availability of models for new devices (MEMS/NEMS, etc.) • Model developers will be receive feedback on the models shortly after release as designers can test them on their simulators without the need to wait for CAD vendors implementations. • Model acceptance speed-up, as the end-users entered in the development loop have had more time to evaluate the model (on real circuits) and, by contributing to it, were able to direct the development effort toward what they really needed. 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  18. GNU perspective - Summary • The EDA community will benefit by using free compact models conforming to an open standard. • A CM DevKit to integrate CM development into IC-CAD flow can be built using only free/open source software. • The core tools of this DevKit are already in place (ADMS, simulators). 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  19. CM Standardization – A GNU perspective Thank you ! 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  20. Modeling overall goal ITRS 2007 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  21. DevKit – EKV example 1 • Simulator independence 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

  22. DevKit – EKV Example 2 1st MOS-AK International Meeting - San Francisco Dec. 13th, 2008

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