Assembly Influence on the Small-Signal Parameters of a Packaged Transistor

Abstract

A detailed analysis of the assembly influence on the small-signal parameters of a packaged transistor is presented. A new method, based on 3D field simulation and mixed-mode scattering parameters approach is proposed. Differences in scattering parameters caused by assembly change are computed using the new proposed method and compared to the standard method based on admittance matrix. The differences, accuracy, error sources and suitability of both methods are discussed. Results are verified experimentally in microstrip line for two fundamental assembly changes of a transistor in SOT 343 package in frequency range 45 MHz - 18 GHz.