Wireless Circuits and Systems: FM Telemetry Devices

This chapter presents frequency modulated (FM) telemetry devices for wireless circuits and systems. A low-power implantable monitoring system in Med-Radio band is introduced and includes a sampling amplifier, and a Gm-C filter, a voltage control oscillator with temperature compensation and bandgap reference (BGR). The chip is designed based on a standard TSMC 0.18-µm CMOS process. The power consumption of the sampling amplifier and Gm-C filter is 10.7 µW and 300 µW, respectively. The cutoff frequency of the filter is 4 MHz. The output frequency of VCO with temperature compensation ranges from 401 MHz to 406 MHz, and the temperature variation coefficient is only 10 ppm/oC. The VCO power consumption is 661 µW. The output voltage of the bandgap reference circuit is 1 V, and the voltage variation coefficient is 0.52%/V. The temperature variation coefficient is 2 ppm/oC, and the power consumption is 131.6 µW. In the temperature measurements, the maximal error is 0.057° with the standard deviation of ±0.034°.