A 2-pJ/b 32-Gb/s D -Band Super-Regenerative Receiver for Energy-Efficient QAM Demodulations

This brief presents aD-band super-regenerative receiver (SRR) that supports energy-efficient QAM demodulations. By introducing super-regenerative operation, the receiver exhibits high gain and tunable bandwidth with low power consumption. The tunable gain and bandwidth enable energy-efficient operation at input signal with different power levels or bandwidths. Besides, a theory-guided optimization method of damping factor is proposed to optimize the performance of the super-regenerative amplifier in the SRR. A prototype was fabricated in a 40-nm CMOS technology. Measurement results show that the SRR achieves peak gains of 32.9 dB and 29.8 dB with 4-GHz and 8-GHz bandwidths, respectively. Furthermore, the proposed SRR supports QAM demodulations in two modes: main-lobe filtering and sub-sampling. Both modes demonstrate the demodulation of 32 Gb/s 16-QAM signals. The receiver presents a power consumption of 64 mW excluding local oscillator (LO) generation, corresponding to an energy efficiency of 2 pJ/bit. To the best of the authors’ knowledge, this is the first demonstration of QAM demodulations using an integrated super-regenerative receiver.