General Description

The MAX8831 integrates a 60mA, 28V PWM DC-DC step-up converter with five low-dropout LED current regulators for display and keypad backlighting in cell phones, PDAs, and other portable devices. The IC provides up to 90 efficiency over the entire input voltage range of 2.7V to 5.5V. The step-up converter operates at a fixed 2MHz switching frequency, enabling the use of very small external components to achieve a compact circuit area. For improved efficiency, the step-up converter automatically transitions to pulse-skipping mode at light loads.

Benefits and Features

• Highly Integrated 28V Step-Up DC-DC Converter with Programmable Functionality Lowers System Cost

   • Integrated NMOS Power Switch

• Two 25mA Regulators for Display Backlighting

   • I2C-Programmable 50µA to 25.25mA Output Current

   • 128-Step Logarithmic Dimming

   • Individually Programmable Ramp (Up/Down) Timers

   • Low Dropout (200mV max)

• Three 5mA Current Regulators for Keypad Lighting with I2C-Programmable 50µA to 5.0mA Output Current

   • 32-Step Logarithmic Dimming

   • Individually Programmable Ramp (Up/Down) Timers

   • Individual Blink Rate and Duty Cycle Timers

   • Low Dropout (150mV max)

   • I2C Programmable Compatible with 1.8V Logic

• Protection Features Increase Reliability

   • Open/Short LED and Open-Circuit Diode Detection

   • Thermal-Shutdown and Output Overvoltage Protection

• High Efficiency and Low Shutdown Current Extend Battery Life

   • > 90 Efficiency

   • Pulse Skipping for Improved Light-Load Efficiency

   • Ultra-Low 0.1µA Shutdown Current

• Small Solution Size Saves Board Space

   • Tiny 2mm x 2mm, 16-Bump WLP Package

   • 2MHz Switching Frequency Allows Use of Tiny External Components

Applications

   Cell Phones

   PDAs

   Smartphones