A 0.5mW passive telemetry IC for biomedical applications

The radiated power received by a small coil in implantable telemetry systems is less than a milliwatt. This requires a very efficient RF to DC converter, as well as the lowest possible power consumption for the biomedical sensor and data acquisition/transmisson system. This paper describes the design of a BiCMOS integrated circuit that includes a low noise amplifier, a lowpass notch filter, an A/D converter, voltage doubler/rectifier as well as a low power voltage regulator. The entire system, including the 1.7kΩ MR bridge sensor, consumes only 520µW average power @3V.