Generation of the HDL-A-model of a Micromembrane from its Finite-element-description Klaus Hofmann 1 , Manfred Glesner 1 , Nicu Sebe 2 , A. Manolescu 2 , Santiago Marco 3 , Josep Samitier 3 , Jean-Michel Karam 4 , Bernard Courtois 4 1 :Darmstadt University of Technology, Institute of Microelectronic Systems, Karlstrasse 15, 64283 Darmstadt / Germany, E-Mail: hofmann@mes.th-darmstadt.de 2 :„Politehnica“ University Bucharest / Romania 3 :University of Barcelona / Spain 4 :INPG / TIMA, Grenoble / France Abstract A CAD-tool for the automated generation of behavioral models in HDL-A is presented. This CAD- tool has been implemented in the frame of a project for automatical modeling of microsystem components for the co-simulation with VHDL- or Spice-Models. Starting from the Finite-Element-description of a microcomponent a nonlinear behavioral HDL-A- model is generated by successively adding or deleting effects to the HDL-A-model according to the observed differences between the two models. Using the example of a micromembrane the practicability of this approach will be demonstrated. This CAD-tool provides a method for decoupling the generation of behavioral models from the Finite-Element-simulation process. 1 Introduction Simulation of heterogeneous systems on the system level implies the simulation of the whole system and that of particular devices with a special emphasis on points of interest like functional behavior, timing, power consumption and so on. Simulation is very closely connected to modeling because only the system- or device-behavior can be simulated that has been taken into account while developing the models. Functional simulation of microsystems and microcomponents can be done efficiently by using a single system description language suitable for a single simulator. The advent of analog HDLs like HDL-A by Anacad, MAST by Analogy and the future standard VHDL-AMS offer the possibility to create behavioral models of electrical and non-electrical devices without having the limitations of Spice. At VHDL-AMS´ stage of infancy not much work is known to the authors concerning the insertion of VHDL-AMS-like descriptions in the design flow for analog or heterogeneous systems (see [MOS95], [ELT93], [ARB91], [SEI95], [SAX95]). The creation of behavioral models for microsystem components causes several problems: • The engineer responsible for creating the behavioral models needs excellent theoretical knowledge about the component as well as excellent know-how about the simulation tools. • No verification of the behavioral models with regard to the 2D/3D FEM-models is done. • There is no quantitative number for the accuracy of the behavioral model for other waveforms than the one used during the creation. • The behavioral models have to obey certain standards concerning system-interfaces, generics etc.. : difficult to manage from the FEM-designers view. Some of the problems mentioned above need to be explained: The main problem for the global functional simulation of microsystems is to create accurate models of micromechanical and microoptical devices in the transient domain. Due to the fact that most system-engineers are not familiar with micromechanics and Finite-element-(FE) modeling and technology- experts do only scarcely know the needs for system- modeling on all levels of interest, in general a simple linear parameter extraction is performed to create a simple behavioral model of that device. With the miniaturization of mechanical and optical devices this will not be sufficient for an accurate simulation of system behavior. Furthermore, the fact that engineers have to be the experts for two CAD-tools in very different domains violates the idea of dividing the work to specialists. ED&TC ’97 on CD-ROM Permission to make digital/hard copy of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for fee or commercial advantage, the copyright notice,the title of the publication, and its date appear, and notice is given that copying is by permission of the ACM, Inc. To copy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and/or a fee.  1997 ACM/0-89791-849-5/97/0003/$3.50