A 400-MHz super-regenerative receiver with digital calibration for capsule endoscope systems in 0.18-μm CMOS

Abstract

A low-power super-regenerative receiver (SR-RX) with a digitally-controlled oscillator for the capsule endoscope system is reported in this paper. In this work, an open-loop frequency calibration loop is proposed to adjust the oscillator center frequency to the desired frequency band. The RX operates in the 402-405 MHz MICS band, and is designed to receive on-off keying modulation signal. This chip was fabricated in the TSMC 0.18-mum CMOS process. The RX start-up time is only 14.8 mus and is capable of a maximum data rate of 1 Mbps. The SR-RX consumes 5.5 mW from a 1.5-V supply voltage.