A 14.5 pW, 31 ppm/°C resistor-less 5 pA current reference employing a self-regulated push-pull voltage reference generator

Abstract

This paper presents a gate-leakage-based supply- and temperature-stabilized current reference generator that can output currents as low as 5 pA with minimal power overhead. The output reference current is generated by driving a set of gate-leakage transistors designed to have opposing temperature coefficients with a stabilized voltage reference. Low-power operation is achieved by generating the voltage reference via a novel two-stage, 4T push-pull structure that can operate at a low supply voltage, and driving this reference to the gate-leakage transistors via a low-voltage self-biased amplifier. Designed in a 65 nm CMOS process, the proposed current reference generator is simulated to consume 14.5 pW at a 0.5 V supply voltage. Due to the push-pull structure and complementary gate-leakage transistors, the design achieves a temperature stability of 31 ppm/°C from 0 °C to 100 ° C, and a line sensitivity of 0.94%/V averaged across 500 Monte Carlo samples, thereby enabling an ultra-low-power, area-efficient, and temperature- and supply-stabilized current reference solution at pA-levels.