The MAX1552 is a complete power management chip for low-cost personal digital assistants (PDAs) and portable devices that operate from 1-cell lithium-ion (Li+), or 3-cell NiMH batteries. It includes all the regulation, output and voltage monitoring necessary for a small PDA, while requiring a minimum of external components. This device features four linear regulators, a step-up DC-DC converter for LCD biasing, microprocessor reset output and low-voltage detection in a tiny QFN package. For lithium-ion chargers compatible with USB and AC adapter inputs, refer to the MAX1551*. Linear regulator with four-element PMOS bypass for efficient low-dropout operation. The main supply of this LDO is 300mA over 3.3V. An SD card slot has a 3.3V output power supply at 200mA. The COR1 200mA LDO output is 1.5V and the LDO power supply is 1.8V COR2 at 20mA. The SD output and COR2 LDO have pin-controlled shutdown. For other output voltage combinations, contact Maxim. The step-up DC-DC converter features an on-board MOSFET and true shutdown when turned off. This means that during shutdown, the input power is disconnected. Therefore, the inductor boosts the output instead of dropping to 0V leaving a diode drop below the input voltage. A microprocessor reset output clears when the input voltage rises to 3.4V to ensure an orderly start. Low battery output warns of impending power loss to safely shut down the system. Thermal shutdown protects from overheat death. The MAX1552 operates from a 5.5V supply from a voltage of 3.1V and consumes 50µA of no-load supply current. This comes in a 1.3W package with 16-pin thin QFN power pads on the bottom of the package. The MAX1552 is operable over a temperature range of -40°C to +85°C