A 5 V-to-3.3 V CMOS Linear Regulator with Three-Output Temperature-Independent Reference Voltages

This paper presents a 5 V-to-3.3 V linear regulator circuit, which uses 3.3 V CMOS transistors to replace the 5 V CMOS transistors. Thus, the complexity of the manufacturing semiconductor process can be improved. The proposed linear regulator is implemented by cascode architecture, which requires three different reference voltages as the bias voltages of its circuit. Thus, the three-output temperature-independent reference voltage circuit is proposed, which provides three accurate reference voltages simultaneously. The three-output temperature-independent reference voltages also can be used in other circuits of the chip. By using the proposed temperature-independent reference voltages, the proposed linear regulator can provide an accurate output voltage, and it is suitable for low cost, small size, and highly integrated system-on-chip (SoC) applications. Moreover, the proposed linear regulator uses the cascode technique, which improves both the gain performance and the isolation performance. Therefore, the proposed linear regulator has a good performance in reference voltage to output voltage isolation. The voltage variation of the linear regulator is less than 2.153% in the temperature range of −40°C–120°C, and the power supply rejection ratio (PSRR) is less than −42.8 dB at 60 Hz. The regulator can support 0~200 mA output current. The core area is less than 0.16 mm2.