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MAX1574：180mA, 1x/2x, White LED Charge Pump in 3mm x 3mm TDFN

White LED Charge Pump in 3mm x 3mm TDFN Achieves 83% Average Efficiency

The MAX1574 charge pump drives up to three white LEDs with regulated constant current for uniform intensity. By utilizing adaptive 1x/2x charge-pump modes and very-low-dropout current regulators, it achieves 180mA output drive capability and high efficiency over the 1-cell lithium-battery input voltage range. Fixed-frequency (1MHz) switching allows for tiny external components, and the regulation scheme is optimized to ensure low EMI and low input ripple. The MAX1574 uses an external resistor to set the fullscale 100% LED current. An enable input (EN) is used for simple on/off control or can be pulsed repeatedly to set lower LED current in multiple steps down to 5%. Once the desired brightness is set, the MAX1574 maintains constant LED current as long as EN is kept high. If EN is kept low for more than 2ms, the MAX1574 enters shutdown. The MAX1574 is available in a 10-pin 3mm x 3mm TDFN package (0.8mm max height).

Key Features Up to 180mA (60mA/LED) Drive Capability 83% Average Efficiency (PLED / PBATT) Over Li+ Battery Discharge 0.5% (typ) LED Current Matching Adaptive 1x/2x Mode Switchover Low Input Ripple and EMI 5% to 100% Dimming Through Single-Wire Serial Pulse Interface Low 0.1µA Shutdown Current 2.7V to 5.5V Supply Voltage Range Soft-Start Limits Inrush Current Output Overvoltage Protection Thermal-Shutdown Protection 10-Pin 3mm x 3mm TDFN Package

MAX1574: Typical Operating Circuit Applications/Uses Camera Strobes/Flashes and Movie Lights Cell Phones/Smartphones LCD Backlights PDAs, Digital Cameras, and Camcorders

DataSheet

Parametrics

Design kits & evaluation modules

• MAX1574EVKIT

Quality and Environmental Data

• MAX1574.pdf

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