A 28 ppm/°C, 2.54 ppm/V, −77 dB@100 Hz pico-ampere voltage reference for high-end IoT systems

This paper presents a pico-ampere voltage reference for IoT systems with high performance in line regulation and power supply rejection ratio (PSRR). Based on the leakage current characteristics of MOSFETs, the reference voltage is obtained by taking advantage of the threshold voltage differences between two types of MOSFETs with different gate oxide thicknesses. By employing a self-regulation technique, the impacts of drain-induced barrier lowering (DIBL), gate-induced drain leakage (GIDL) and gate-drain capacitance feedthrough effects can be mitigated, resulting in high performance in line regulation and PSRR. Based on a 0.18 μm standard CMOS process, post-layout simulation results show the temperature coefficient is 28.0 ppm/°C over the temperature range of 0–120 °C with a 0.6 V supply voltage. The line regulation is 2.54 ppm/V, which is at least two orders of magnitude lower than existing designs in the literature. The PSRR is −77 dB@100 Hz that is improved by at least 10 dB over existing designs in the literature.