The SP6656 is a 400mA synchronous buck regulator that is ideal for portable applications that use a Li-Ion or 3 cell alkaline/NiCD/NiMH input. The SP6656's proprietary control loop, 20A light load quiescent current, and 0.3 power switches provide excellent efficiency across a wide range of output currents. As the input battery supply decreases towards the output voltage the SP6656 seamlessly transitions into 100% duty ratio operation further extending useful battery life. The SP6656 is protected against overload and short circuit conditions with a precise inductor peak current limit. Other features include externally programmable output voltage down to 1.0V, logic controlled output voltage selection, logic level shutdown control, and 140C over temperature shutdown.