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MAX1573：White LED 1x/1.5x Charge Pump in UCSP and Thin QFN

Smallest, Highest Efficiency White LED Charge Pump Packaged in a UCSP™

The MAX1573 fractional charge pump drives up to four white LEDs with regulated constant current for uniform intensity. By utilizing proprietary adaptive 1x/1.5x modes and ultra-low-dropout current regulators, it maintains the highest possible efficiency over the full 1-cell Li+ battery input voltage range. The 1MHz fixed-frequency switching allows for tiny external components and the regulation scheme is optimized to ensure low EMI and low input ripple. An external resistor sets the full-scale LED current, while two digital inputs control on/off and select amongst three levels of brightness. A pulse-width modulation (PWM) signal can also be used to modulate LED brightness, requiring no additional components. The MAX1573 is available in the tiny chip-scale UCSP™ (4 x 4 grid) and 16-pin thin QFN packages.

Key Features Proprietary Adaptive 1x/1.5x Modes High Efficiency (PLEDs/PBATT), Up to 92% 0.2% LED Current Matching 28mA/LED Drive Capability Low Input Ripple and EMI Eliminates Ballast Resistors Logic or PWM Dimming Control Low 0.1µA Shutdown Current 2.7V to 5.5V Input Voltage Range Soft-Start Limits Inrush Current Output Overvoltage Protection Thermal Shutdown Protection No External Schottky Diode Required Tiny UCSP (2.1mm x 2.1mm x 0.6mm) and Thin QFN (4mm x 4mm) Packages

MAX1573: Typical Operating Circuit Applications/Uses Cell Phones/Smartphones MP3 Players Other Handhelds with Color Displays PDAs, Digital Cameras, and Camcorders

DataSheet

Parametrics

Design kits & evaluation modules

• MAX1573EVKIT

Quality and Environmental Data

• MAX1573.pdf

Ordering Information