The LTC3531-3 from Analog Devices is a Synchronous Buck-Boost DC-DC Converter that converts an input voltage of 1.8 - 5.5 V to an output voltage of 2 - 5 V. It delivers efficiency of up to 90%. This DC-DC converter consists of two 0.5 Ω N-channel MOSFET switches and two 0.5 Ω and 0.8 Ω P-channel switches. It operates in burst mode to minimize solution footprint and component count while providing high conversion efficiency over a wide range of load currents. The DC-DC converter is equipped with a built-in current limiter, thermal shutdown, and output disconnecting function to prevent short-circuit-related damages. It is available in a surface-mount package that measures 3 x 3 x 0.75 mm and is ideal for PDA, GPS, MP3 players, handheld instruments, and handheld computer applications.