General Description
The MAX1570 fractional charge pump drives up to five white LEDs with regulated constant current for uniform intensity. The MAX1570 maintains the highest possible efficiency over the full 1-cell lithium-ion (Li+) battery input voltage range by utilizing a 1x/1.5x fractional charge pump and very-low-dropout current regulators.

Features
♦ Excellent 0.3% LED-to-LED Current Matching
♦ 30mA/LED Drive Capability
♦ Proprietary 1x/1.5x Modes for Ultra-High
   Efficiency
♦ Low Input Ripple and EMI
♦ Eliminates Ballast Resistors
♦ Digital or PWM LED Dimming Control
♦ 0.1µA Shutdown Current
♦ 2.7V to 5.5V Supply Voltage Range
♦ Soft-Start Limits Inrush Current
♦ Thermal-Shutdown Protection
♦ No External Inductor, Schottky, or Zener Diode
   Required
♦ Tiny 16-Pin 4mm ✕ 4mm Thin QFN Package

Applications
   White LED Backlighting
   Cell Phones and Smart Phones
   PDA and Palmtop Computers
   Portable MP3 Players
   Digital Cameras and Camcorders