Abstract- The paper presents a methodology for simulating the static and dynamic performance of integrated circuits in the presence of electro-thermal interactions on the integrated circuit die. The technique is based on the coupling of a finite element method (FEM) program with a circuit simulator. In difference to other known simulator couplings a time step algorithm is used. Its implementation into simulation tools is described. The thermal modeling of the die/package structure and the extended modeling of the electronic circuit is discussed. Simulation results which indicate the capabilities of the methodology for electrothermal simulation are compared to experimental results. Index Terms- Analog modeling with behavioral languages, circuit simulation, electro-thermal circuit simulation, finite element simulation, simulator coupling, thermal modeling. I.