A Low Power Low Supply MOS-Only Subthreshold Voltage Reference for Wide Temperature Range

Abstract

A Sub-1V, MOS-only Voltage Reference Circuit (VRC) has been proposed with the utmost of transistors working as subthreshold region for low-supply and low-power applications. A supply-insensitive current is passed to Active Load Circuit (ALC) for supply and temperature independence at the output reference voltage. It has four current mirrors connected in a closed loop configuration to generate a supply-independent current which is passed through the ALC resulting supply and temperature insensitive output reference voltage. The ALC has a combination of two subthreshold NMOS transistors having different threshold voltages. The presented VRC is simulated using standard 90 nm CMOS model for 0.25-1 V supply voltage range. The simulation result gives minimum operating voltage required as 0.25 V for which all transistors work in their respective region of operation. For the supply range of 0.25-1 V, the obtained mean voltage reference is 100.4 mV with the line regulation of 0.186 mV/V. The temperature coefficient (TC) of 51ppm/°C is achieved for a wide temperature range of -50 to 135°C with the given minimal operating supply voltage. The power dissipation for minimal supply voltage at room temperature is 33 nW. The proposed VRC exhibits a high PSRR of -52.5 dB at 100Hz and -29 dB at 1 MHz.