A 0.5-nW 29ppm/°C Voltage Reference Circuit

This paper presents a novel sub-nW voltage reference circuit for ultra-low-power systems. It saves power by using a 2-transistor (2-T) structure that produces a stable voltage based on transistor threshold voltage difference. A well-controlled bias current is produced by a novel current generator that reduces the temperature coefficient (TC). Fabricated in 180nm CMOS process, this reference circuit consumes only 0.5nW power. It achieves an average TC of 29ppm/°C and a line sensitivity (LS) of 0.18%/V, measured across 22 chips.