Tools for Model-based Design and Test

Tools for Model-based Design and Test Martin Vlach Lynguent, Inc. 2828 SW. Corbett Ave., Ste 122 Portland, OR 97201 Ph: 503-241-7195 mvlach@lynguent.com H. Alan Mantooth Mixed-Signal CAD Laboratory University of Arkansas Fayetteville, AR 72701 Ph: 479-575-4838 mantooth@{lynguent.com,uark.edu}

Outline • Compact modeling yesterday and today • C based • Verilog-A based with compilers • Compact modeling tomorrow • Conceptual level methodology • Importing legacy HDL models • Optimized for ADMS compilation • Advanced diagnostics • Self-documenting • Reusable effects • PDK support • Model-based toolkits • Multi-lingual from single root • Conclusions

Yesterday and Today • Compact modeling yesterday and today • C based • Simulator data structures • Unwieldy code • Typically, poorly documented • Underanalyzed • Derivatives • Verilog-A based with compilers • Still totally code based • Underanalyzed • Maintenance for multiple simulators

Paragon/ModLyng

Tomorrow • Conceptual • Importing • Optimized • Diagnostics • Self-documenting • Reusable effects • PDK support • Toolkits • Multi-lingual Focus on what to model, not how

Tomorrow • Conceptual • Importing • Optimized • Diagnostics • Self-documenting • Reusable effects • PDK support • Toolkits • Multi-lingual • Reuse legacy HDL code as either: • A starting point for modification or • Perhaps a migration to another format

Tomorrow • Conceptual • Importing • Optimized • Diagnostics • Self-documenting • Reusable effects • PDK support • Toolkits • Multi-lingual Code generation understands parameters, constants, etc.

Tomorrow • Conceptual • Importing • Optimized • Diagnostics • Self-documenting • Reusable effects • PDK support • Toolkits • Multi-lingual • Produce plots of evaluated code • Check continuity • Perform differentiation

Tomorrow • Conceptual • Importing • Optimized • Diagnostics • Self-documenting • Reusable effects • PDK support • Toolkits • Multi-lingual • Modeling at this level IS documentation • Tool clearly does more to convey model functionality than simply code analogous to a state machine diagram

Tomorrow • Conceptual • Importing • Optimized • Diagnostics • Self-documenting • Reusable effects • PDK support • Toolkits • Multi-lingual Compact models often have many of the same effects

Tomorrow • Conceptual • Importing • Optimized • Diagnostics • Self-documenting • Reusable effects • PDK support • Toolkits • Multi-lingual Elimination of PDK macromodels and scripts for geometric, thermal, and correlative effects

Tomorrow • Conceptual • Importing • Optimized • Diagnostics • Self-documenting • Reusable effects • PDK support • Toolkits • Multi-lingual Complete with regression analysis, commonly used graph definitions, commonly used diagnostics.

Tomorrow • Conceptual • Importing • Optimized • Diagnostics • Self-documenting • Reusable effects • PDK support • Toolkits • Multi-lingual • Can generate multiple HDLs • Can generate code for multiple simulation platforms • API-based, so user-definable

Transistor Modeling Demonstration of BSIM4 • Import • Documented BSIM4 • Search • Threshold voltage • BSIM4 improvement through ModLyng

Conclusions • Compact modeling continues moving toward a new approach • Foundation is comprehensive • ModLyng is equally valid for analog and mixed-signal behavioral modeling • Much more to tell such as: • CMX: open source format • Effects modeling • Extensions to mixed-signal • Model synthesis tools

Block example Q6 Q5 Q1 Q2 Q7 Q8 Q3 Q4 Ictrl RL RL I1 Vo+ Ibias Vo- In+ Re In- Ictrl

Bias Current Circuit Start-up PTAT voltage generator Gm/ID regulator

Model of Bias Current • I vs. T I = 0.0645*T + 4.65 mA p I(T) m

Tools for Model-based Design and Test