A Ultra Low Supply Voltage Bandgap Reference Based on Substrate Bias

A CMOS bandgap reference (BGR) capable of operating at supply voltage of 0.9V was proposed in this paper. To guarantee its normal operation at ultra low supply voltage, the substrate bias techniques is used to reduce the threshold voltage. Meanwhile, an amplifier biased by subthreshold current is designed. This circuit is designed in tsmc 0.35μm CMOS technology. An average reference voltage of 658mV with a temperature coefficient of 18.5 ppm/°C is achieved.