A 0.45V 687pW low noise amplifier front-end with 1.73 NEF for energy-scavenging IoT sensors

This paper presents a sub-nanowatt front-end amplifier for ultra-low-power wireless IoT sensor nodes. This chip consists of an instrumentation amplifier, a DC servo loop, a clock generator and a bias circuit. It is fully integrated, and therefore does not rely on any off-chip references. Fabricated in 65nm CMOS process, measurement results show that the amplifier system achieves 39dB gain and 0.1–130Hz bandwidth, sufficient for many low-frequency sensor interface applications. The measured power is 687pW for a 0.45V supply voltage, which when compared with previously published AFEs, is the only sub-nW low-noise amplifier.