Towards Ultra-Low-Voltage and Ultra-Low-Power Discrete-Time Receivers for Internet-of-Things

In this paper, we investigate an impact of voltage supply scaling on power consumption and performance of a new class of wireless receivers (RX) for Internet-of-Things (IoT) applications: a discrete-time (DT) superheterodyne architecture realized in nanoscale CMOS using inverter-based gm and switched capacitors. The power supply is partitioned into three separate domains: RF, intermediate frequency (IF) processing, and clocking, which allows them to be independently regulated to assess their respective impact. The DT-RX maintains its functionality, albeit with some acceptable loss of performance, when the core supplies are varied by as much as an octave, i.e., from the nominal 1.1 V down to 0.55V. The DT-RX IC is then connected to a switched-capacitor based voltage doubler array on a companion IC die such that the DT-RX can be powered at the octave range of 0.275-0.55 V from an energy harvester. The sensitivity at the doubler's 0.275/0.55 V input is -85/-95 dBm while consuming 1.0/2.4mW. Both ICs are implemented in TSMC 28-nm LP CMOS.