0.5-V operational transconductance amplifier for CMOS bandgap reference application

A positive feedback technique that make possible the operation of operational transconductance amplifier (OTA) with very low supply voltage, down to 0.5V, is proposed. The MOSFETs providing quasi-linear temperature characteristic are used along with the proposed OTA to design a low voltage bandgap reference circuit. The 0.045-mm
²
chip fabricated in SMIC 0.18-mum CMOS process generates 0.4V reference voltage with the supply down to 0.56V with a maximum temperature coefficient of 80ppm/degC, The total current is 4.8 muA at the room temperature