A 228µW injection locked ring oscillator based BPSK demodulator in 65nm CMOS

This paper presents an ultra-low power BPSK demodulator based on injection locked oscillators (ILOs). Two second harmonic ILOs are employed to convert BPSK signals to ASK signals which are demodulated by an envelope detector to baseband signals. For sub-GHz applications, the ILOs are implemented using ring oscillators to allow compact chip area and ultra-low power dissipation. The prototype demodulator is fabricated in a 65nm CMOS technology that consumes 228μW of power and occupies 0.014mm² of die area. Measurement results reveal the demodulation of BPSK signal at 750-900MHz carrier with the minimum sensitivity of -33dBm.