Texas Instruments TPS63051RMWT, 1 Buck Boost Switching, Boost/Buck Converter 500mA, 3.3 V, 2.5 MHz 12-Pin, VQFN

This highly efficient buck-boost converter uses a single inductor for DC to DC conversion. With automatic transmission between its Step Down and Step Up functions, buck-boost converters can be employed in battery powered products that use either a two-cell and three-cell alkaline battery, a NiCd or NiMH, or a single cell Lithium battery. This makes it ideal for use with cellular phones and similar hand-held devices.

DC/DC Switching Regulator Converters (Integrated Switch), Texas Instruments

The range of highly integrated high-efficiency switching voltage regulators from Texas Instruments includes Step-up (Boost), Step-down (Buck), Step-up/down (Boost/Buck) and Inverting types providing efficient solutions for every DC Voltage Regulator application.