The MIC23031 is a high efficiency 4MHz 400mA synchronous buck regulator with Hyper Light LoadTM mode. Hyper Light LoadTM provides very high efficiency at light loads and ultra-fast transient response which is perfectly suited for supplying processor core voltages. An additional benefit of this proprietary architecture is very low output ripple voltage throughout the entire load range with the use of small output capacitors. The tiny 1.6mm x 1.6mm Thin MLF package saves precious board space and requires only three external components. The MIC23031 is designed for use with a very small inductor, down to 0.47H, and an output capacitor as small as 2.2 F that enables a sub-1mm height. The MIC23031 has a very low quiescent current of 21A and achieves as high as 88% efficiency at 1mA. At higher loads, the MIC23031 provides a constant switching frequency around 4MHz while achieving peak efficiencies up to 93%.