GENERAL DESCRIPTION
Featured are three linear regulators, a boost DCDC converter for LCD bias, an efficient 4MHz buck DC-DC converter for core power, a microprocessor (µP) reset output, and low-battery shutdown in a 0.8mm high thin QFN package. All linear regulators feature PMOS pass elements for efficient low-dropout operation. A MAIN LDO supplies 3.3V at 500mA. A securedigital (SD) card slot output supplies 3.3V at 500mA, and a COR2 LDO supplies 1.8V at 50mA. Each output has its own logic-controlled enable. For other output voltage combinations, contact 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 the boost output 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, the COR1 regulator is not started until the 3.3V main output is in regulation.
Maxim Integrated
