Compact model standardization – a GNU perspective Paolo Nenzi

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

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 Franci sco Dec. 13th, 2008

Perspectives 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. 1st MOS-AK International Meeting - San Franci sco Dec. 13th, 2008

Consequences 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.) 1st MOS-AK International Meeting - San Franci sco Dec. 13th, 2008

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 Franci sco Dec. 13th, 2008

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 Franci sco Dec. 13th, 2008

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 Franci sco Dec. 13th, 2008

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 Franci sco Dec. 13th, 2008

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 Franci sco Dec. 13th, 2008

The CM DevKit – key tools 1. 2. 3. 4. 5. 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 Franci sco Dec. 13th, 2008

The CM DevKit – Model Capture 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. 1st MOS-AK International Meeting - San Franci sco Dec. 13th, 2008

The CM DevKit – Model synthesizer 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. 1st MOS-AK International Meeting - San Franci sco Dec. 13th, 2008

The CM DevKit – Intermediate languages 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. 1st MOS-AK International Meeting - San Franci sco Dec. 13th, 2008

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

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 Franci sco Dec. 13th, 2008

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

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 Franci sco Dec. 13th, 2008

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 Franci sco Dec. 13th, 2008

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

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

DevKit – EKV example 1 Simulator independence Simulator ADS Version* EKV2.6 LEVEL 2003C Altium EKV3.0 LEVEL Verilog-A 6.5 Verilog-A 8 3.7a 23 APLAC 7.30h EKVMOS AVOSpice 1.82.0805 Verilog-A Verilog-A 44 (UPDATE 2.6) 61 Verilog-A ekv ekv3 4.6 Golden Gate 4 HSIM 2 example [wg] Released Aug.30 2006 AMI-Spice ELDO Comments released to be announced in beta 55 IntuSoft ICAP/4 LTspice/SwitcherCAD III 1.09p 12 free download MacSpice 3f5p10 44 free download MI-SUGAR 0.4.4 44 Mac OSX Micro-Cap 8.0.0 44 available now MINIMOS-NT NanoSpice shipping 2 1.1 Devices.{N;P}MosEkv with selfheating 55 1st MOS-AK International Meeting - San Franci sco Dec. 13th, 2008

DevKit – EKV Example 2 Simulator Version* Nexxim NG-Spice 1 rev.17 PSPICE [*] 0.0.14 SABER 4.3.2 SIMetrix Verilog-A Verilog-A 4.1 Spectre 4.43 6 SPICE3 Verilog-A released Feb 2002 55 SMASH Spice-Opus free download thru XML-ADMS 44 1.5.5.R Comments Verilog-A Verilog-A 5 4.1 SpectreRF EKV3.0 LEVEL 55 9 Qucs SmartSpice EKV2.6 LEVEL 5 ekv3 and Verilog-A released ekv Verilog-A tested at LEG ekv Verilog-A 2.04 3f5 44 Verilog-A Verilog-A available Verilog-A tested [wg] Star-Hspice 98.4 55 Verilog-A also CML libs Synopsys 98.4 55 Verilog-A also CML libs Verilog-A also CML libs T-Spice 11 44 or 55 TopSPICE 6.9 44 or 55 TRANZ-TRAN 3.5 WinSpice 1.03.02 44 1st MOS-AK International Meeting - San Franci sco Dec. 13th, 2008 free download