Embedded 5V-to-3.3V voltage regulator for supplying digital ICs in 3.3V CMOS technology

A fully-integrated 5V-to-3.3V supply voltage regulator for application in digital ICs has been designed in a 3.3V 0.5µm CMOS process. The regulator is able to deliver peak current transients of 300mA while the output voltage remains within a margin of 10% around the nominal value. The circuit draws a static quiescent current of 1mA during normal operation and includes also a power-down mode with only 12µA current consumption. The die area is 1mm²and can be scaled proportional to the maximum peak current. Special precautions have been taken to allow 5V in the 3.3V process.