Simplified Block Diagram
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- Minimum External Components
- 4 Linear Regulator Outputs
- Main LDO 3.3V, 300mA
- SD Card Output 3.3V, 200mA
- Core LDO 1.5V, 200mA
- 2nd Core LDO 1.8V, 30mA
- High-Efficiency LCD Step-Up DC-to-DC Output
- Up to 28V
- LCD 0V True Shutdown When Off
- 50µA Quiescent Supply Current
- 1.3W Thin QFN Package
- Cell Phones/Cordless Phones
- Handheld Devices
- MP3 Players
The four linear regulators feature PMOS pass elements for efficient low-dropout operation. The MAIN LDO supplies 3.3V at over 300mA. An SD card slot output supplies 3.3V at 200mA. The COR1 LDO outputs 1.5V at 200mA and the COR2 LDO supplies 1.8V at 20mA. The SD output and COR2 LDOs have pin-controlled shutdown. For other output voltage combinations, contact Maxim.
The step-up DC-to-DC converter features an on-board 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 when the input voltage rises to 3.4V to ensure an orderly start. A low-battery output warns the system of impending power loss for safe shutdown. Thermal shutdown protects the die from overheating.
The MAX1552 operates from a 3.1V to a 5.5V supply voltage and consumes 50µA 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 MAX1552 is specified for operation from -40°C to +85°C.