The MAX17017 is a quad output controller for ultra-mobile portable computers (UMPCs) that rely on a low-power architecture. The MAX17017 provides a compact, low-cost controller capable of providing four independent regulators—a main stage, a 3AP-Pinternal step-down, a 5AP-Pinternal step-down, and a 2A source/sink linear regulator.The main regulator can be configured as either a step-down converter (for 2 to 4 Li+ cell applications) or as a step-up converter (for 1 Li+ cell applications). The internal switching regulators include 5V synchronous MOSFETs that can be powered directly from a single Li+ cell or from the main 3.3V/5V power stages. Finally, the linear regulator is capable of sourcing and sinking 2A to support DDR termination requirements or to generate a fixed output voltage.The step-down converters use a peak current-mode, fixed-frequency control scheme—an easy to implement architecture that does not sacrifice fast-transient response. This architecture also supports peak current-limit protection and pulse-skipping operation to maintain high efficiency under light-load conditions.Separate enable inputs and independent open-drain power-good outputs allow flexible power sequencing. A soft-start function gradually ramps up the output voltage to reduce the inrush current. Disabled regulators enter high-impedance states to avoid negative output voltage created by rapidly discharging the output through the low-side MOSFET. The MAX17017 also includes output undervoltage, output overvoltage, and thermal-fault protection.The MAX17017 is available in a 48-pin, 6mm x 6mm Thin QFN package.Applications1-to-4 Li+ Cell Battery-Powered DevicesLow-Power ArchitectureNotebook and Subnotebook ComputersPDAs and Mobile CommunicationPortable GamingUltra-Mobile PC (UMPC)