Manufacture of custom CMOS LSI for an implantable multipurpose biotelemetry system

Implantable biotelemetry systems are indispensable tools not only in animal research but also in clinical medicine as such systems enable the acquisition of otherwise unavailable physiological data. This paper describes the manufacture of custom CMOS LSI to implement an implantable biotelemetry system. The internal circuits of this system are fabricated on a single silicon chip with a size of 4 x 5 mm. This IC is designed and manufactured not only to achieve as small size and low power dissipation as possible, but also to have multiple functions. Its main functions are to select one of implanted sensors and to accomplish On-Off power switching of an implanted battery by receiving appropriate control signals and command signals from an external circuit. This system, used together with appropriate sensors, is expected to be capable of measuring and transmitting such significant parameters as pressure, pH and temperature.