The inductive connection effects of a mounted SPDT in a plastic SO8 package

An investigation of the electrical performance of an assembled SO8 package is presented. The structure analyzed is based on the plastic SO8 package used for CMS applications assembled with a single-pole, double-throw (SPDT) switch integrated circuit. Using an equivalent electric network elaborated for the whole assembly, the isolation and the insertion losses are computed for a signal frequency up to 5 GHz. Modeling and simulation results show that the effect of the path connection to ground is significant. The results show that the SO8 package is suitable for applications up to 2 GHz (1.4 dB of insertion losses and 22 dB of isolation). The analysis of the insertion losses shows that the inductive bondings are the main sources of this limitation. It is pointed out that these inductive bonding effects must be reduced when higher frequencies are planned; reduction of the length and the distance to the ground would be required.<>