High-order temperature compensated CMOS bandgap reference

A high-order temperature compensated bandgap reference (BGR) based on CSMC 0.5-μm 2P3M n-well mixed signal CMOS process is presented. This novel proposed CMOS bandgap reference takes advantage of both a Buck's voltage transfer cell and a temperature independent current, to provide a high-order temperature compensation of the base-emitter voltage VBE. Cascode structures are also introduced in this CMOS bandgap reference to improve the power supply rejection ratio (PSRR). This circuit achieves 5.6 ppm/°C of temperature coefficient with temperature range from -20 to 100°C at 5 V power supply. The variation in the output voltage of the bandgap reference is 0.4 mV when power supply changes from 4 V to 6 V.