MAX8594A

The MAX8594/MAX8594A complete power-management hips for low-cost personal digital assistants As) operates from a 1-cell lithium-ion (Li+) or 3-cell NiMH battery. They include all regulators, outputs, and oltage monitors necessary for small portable devices hile requiring a bare minimum of external components. eatured are three linear regulators, a boost DCDC onverter for LCD bias, an efficient 4MHz buck C-DC converter for core power, a croprocessor (µP) reset output, and low-battery shutdown in a 0.8mm igh thin QFN package.

he COR1 buck DC-DC converter supplies a pin-selectable utput at 400mA. All linear regulators feature MOS pass elements for efficient low-dropout operation. MAIN LDO supplies 3.3V at 500mA. A securedigital SD) card slot output upplies 3.3V at 500mA, nd a COR2 LDO supplies 1.8V at 50mA. Each output as its own logic-controlled enable. For other output oltage combinations, ntact Maxim.

An LCD bias boost DC-DC converter features an onboard MOSFET and True Shutdown™ when off. This means that during shutdown, input power is disconnected from the inductor so output the boost falls to 0V rather than remaining one diode drop below the input voltage.

A µP reset output clears 20ms (typ) after the COR1 output achieves regulation to ensure an orderly start. In addition,is n the COR1 regulator ot started until the 3.3V main output is in egulation. Also included are a 1% accurate reference and low-battery monitor. Thermal shutdown protects the die from verheating.The AX8594/MAX8594A operate from a 3.1V to a 5.5 supply voltage and consume 46µA no-load supply current. They are packaged in a tiny, 4mm x 4mm, 4-pin thin QFN capable of dissipating 1.67W. The devicesare specified for operation from -40°C to +85°C.