A CMOS Voltage Reference Based on Threshold Voltage for Ultra Low-Voltage and Ultra Low-Power

This work describes a CMOS voltage reference using only resistors and transistors working in weak inversion, without any bipolar transistors. The circuit operation is similar to bandgap references, but the voltage reference is given by the threshold voltage of an nMOS transistor. The circuit was implemented in a standard 0.35μm TSMC CMOS process. The circuit generates a reference of 514mV for a power supply of just 900mV and presents a 20 ppm/°C variation for the range of 0°C a 100°C.