The LTC®3605 is a high effi ciency, monolithic synchronousstep-down switching regulator that is capable of delivering5A of continuous output current from input voltages of4V to 15V. Its compact 4mm × 4mm QFN package hasvery low thermal impedance from the IC junction to thePCB, such that the regulator can deliver maximum powerwithout the need of a heat sink. A single LTC3605 circuitcan power a 1.2V microprocessor directly from a 12Vrail—no need for an intermediate voltage rail.