A Frequency Accuracy Enhanced Sub-10 mu W On-Chip Clock Generator for Energy Efficient Crystal-Less Wireless Biotelemetry Applications

Abstract

A frequency accuracy enhanced clock generator is proposed for energy efficient crystal-less WBAN system. By applying a self-reference calibration and tracking a remote downlink wireless reference, the robust system clock with +/- 30ppm accuracy against both 20% voltage variation and 75 degrees C temperature variation is developed to enable over-Mbps uplink data transmission. Furthermore, the clock generator based on hysteresis delay cells consumes 7.6 mu W in 5MHz and is able to minimize significant always-on clock source power.