Micro-transponder systems for medical applications

The low power consumption of CMOS electronics with on-chip cointegrated sensors or actuators make it ideal for use in implanted systems that need a very low power consumption. Three examples are presented here, which are powered by the energy of an external RF-field. The first microsystem described is a system for measuring the intraocular pressure (IOP). Second, a system for measuring blood pressure will be introduced The third system is used for stimulating the nerve cells of the retina of patients suffering from retinitis pigmentosa. Typical microsystem chip dimensions are about 2.5 mm × 2.5 mm and typical power consumption is about 240 (mu)W