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