Compact thermal model for transient temperature fields in electronic systems

A thermal model is presented, which describes the evolution of the temperature distribution in electronic systems. Introducing a set of deliberately chosen effective time constants, the time dependence is given by convolution integrals with the dissipated power, which are independent of position. Multiplying with a low order matrix which depends on position but not on time, the temperature field is obtained. The matrix constitutes the model and is fitted with a linear and fast algorithm to measurement or simulation. The number of space positions for which the matrix is defined may be reduced arbitrarily to locations of interest to obtain a compact model. As a consequence of the separation of the variables of position and time, a very fast and accurate calculation of the temperature evolution in MCM (multi-chip-modules) is achieved which is beyond the possibilities of FEM-analysis in the case of power pulses over long time intervals. The thermal interaction of different chips in a MCM is investigated.