Techniques to Achieve High Isolation with GaAs MMIC Switch Chips

The achievable isolation of a GaAs MMIC switch is a function of how low an inductance one can achieve between the ground pad of the MMIC and the ground plane within a particular circuit. The lower the inductance, of course, the higher the isolation that can be achieved.

For example, the curves shown for the MASW6010G* chip in the catalog were obtained using coplanar RF probes directly on the chip Because this is a coplanar probe configuration (which also includes the ground plane), there is virtually no ground inductance in the measurement. Thus, the isolation obtained in the data sheet is for a very small ground inductance that exists and should be considered optimum.