Simplified Block Diagram
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- Minimal External Components
- 3.3V, 500mA MAIN LDO
- 3.3V, 400mA SD Card Output
- 1V, 250mA Core LDO
- 1.8V, 30mA Second Core LDO
- High-Efficiency LCD Boost
- LCD 0V True Shutdown when Off
- 50µA Quiescent Current
- 3.1V to 5.5V Input Range
- Cell Phones/Cordless Phones
- Handheld Devices
- MP3 Players
The four linear regulators feature PMOS pass elements for efficient low-dropout operation. A MAIN LDO supplies 3.3V at 500mA. A signal-detect (SD) card-slot output supplies 3.3V at 400mA. The COR1 LDO outputs 1V at 250mA, and the COR2 LDO supplies 1.8V at 30mA. The SD output and COR2 LDO have pin-controlled shutdown. For other output-voltage combinations, contact Maxim.
The DC-DC boost converter features an on-board MOSFET and True Shutdown when off. This means that during shutdown, input power is disconnected from the inductor so that the boost output falls to 0V rather than remaining one diode drop below the input voltage.
A µP reset output clears when the MAIN LDO achieves regulation to ensure an orderly start. Thermal shutdown protects the die from overheating.
The MAX1559 operates from a 3.1V to 5.5V supply and consumes 50mA of no-load supply current. It is packaged in a 1.3W, 16-pin thin QFN with a power pad on the underside of the package. The MAX1559 is specified for operation from -40°C to +85°C.