An Ultralow Power Multirate FSK Demodulator With Digital-Assisted Calibrated Delay-Line Based Phase Shifter for High-Speed Biomedical Zero-IF Receivers

An ultralow power (ULP), multirate frequency shift keying (FSK) demodulator applied for high-speed biomedical zero-IF receivers is presented. A digital-assisted calibrated delay-line (DL) based phase shifter is used for realizing multirate and low jitter demodulation under reported highest data rate. All circuits are operated in subthreshold region for achieving ULP consumption. Moreover, the power consumption of the demodulator is relative to the data rate. Therefore, energy consumption per received bit can be optimized according to the applications. Implemented in 0.18 μm CMOS process, a minimum energy consumption of 11 pJ per received bit and demodulated peak-to-peak jitter of 1.89 ns are achieved under the maximum data rate of 40 Mb/s.