A Low-Voltage Process Corner Insensitive Subthreshold CMOS Voltage Reference Circuit

A reference voltage circuit is presented for generating a constant reference voltage of 278mV using subthreshold characteristics of 0.18μm CMOS technology at supply voltages from 0.8V to 2.6V with total current of 3.6μA. The threshold voltage variation due to process corner variation is minimized by a threshold voltage tracking technique between the normal and high threshold NMOS transistors. In the mean time, channel-length modulation effect is also compensated. The proposed circuit on chip area of 0.04mm
²
achieves the total reference voltage variation of 2.5mV for various process corners and temperature variation from -20°C to 120°C.