An energy-efficient super-regenerative ASK receiver with a ΔΣ-based pulse-width demodulator

An energy-efficient ASK receiver (RX) designed for bio-medical application is presented. The RX is based on the super-regenerative architecture and incorporates a fast frequency calibration and a ΔΣ-based pulse-width demodulator (ΔΣ-based PWD) to enhance the pulse-width resolution of the demodulator. This RX is designed to operate at the 400-MHz band. The proposed fast frequency calibration based on the SAR algorithm can accomplish the frequency calibration in 12 reference cycles. The proposed ΔΣ-based PWD can be viewed as a pulse-width domain ΔΣ modulator which improves the performance of the demodulator. Realized in a 0.18-μm CMOS process, this RX draws 1.37 mA from a 1-V supply. With a 1-Mbps data rate, the RX achieves an energy efficiency of 1.37 nJ/bit and -75 dBm sensitivity.