Design Procedure of Subbandgap Voltage Reference for Energy Harvesting Power Management Unit in 65 nm CMOS Technology

This paper presents the design procedure of subbandgap voltage reference intended for energy harvesting systems. The circuit provides a stable nominal output voltage of 1 V, cross supply voltage range from 1.4 to 2.5 V. The best achieved temperature coefficient is 35 ppm/°C, with an average value of 48 ppm/°C over 12 samples Vdd. The designed circuit exhibits strong immunity against supply voltage fluctuation and good overall stability, with an average power supply rejection ratio of 54 dB. Implemented in 65 nm CMOS technology, the circuit occupies an area of 280 × 213 µm2 and consumes an average current of 32 µA under supply voltage range from 1.4 to 2.5 V.