Adjustable Output CMOS Voltage Reference Design

In this brief, a CMOS voltage reference based on mutual temperature compensation using NMOS transistors of the same threshold type is advanced. The technique consists in subtracting two voltages that present similar complementary-to-absolute-temperature (CTAT) behavior, which are appropriately generated from the same threshold-type NMOS transistors operating as diodes in different inversion levels. The proposed topology provides an adjustable voltage and avoids the use of start-up drivers. The circuit design was carried out in a 180 nm CMOS process. Experimental results verified the effectiveness of the presented technique, and produced a reference voltage of 500 mV. The circuit operates with a supply voltage ranging from 1.2 V to 1.8 V, consumes $4.7~\mu \text{A}$ at 27 °C, has a temperature coefficient (TC) of 22 ppm/°C from 0 °C to 100 °C, and presents a power supply rejection ratio (PSRR) of −42 dB.