General Description

The MAX8640Y/MAX8640Z step-down converters are optimized for applications where small size, high efficiency, and low output ripple are priorities. They utilize a proprietary PWM control scheme that optimizes the switching frequency for high efficiency with small external components and maintains low output ripple voltage at all loads. The MAX8640Z switches at up to 4MHz to allow a tiny 1µH inductor and 2.2µF output capacitor. The MAX8640Y switches at up to 2MHz for higher efficiency while still allowing small 2.2µH and 4.7µF components. Output current is guaranteed up to 500mA, while typical quiescent current is 28µA. Factory-preset output voltages from 0.8V to 2.5V eliminate external feedback components.

Internal synchronous rectification greatly improves efficiency and replaces the external Schottky diode required in conventional step-down converters. Internal fast soft-start eliminates inrush current so as to reduce input capacitor requirements.

The MAX8640Y/MAX8640Z are available in the tiny 6-pin, SC70 (2.0mm x 2.1mm) and µDFN (1.5mm x 1.0mm) packages. Both packages are lead-free.

Features

♦ Tiny SC70 and µDFN Packages

♦ 500mA Guaranteed Output Current

♦ 4MHz or 2MHz PWM Switching Frequency

♦ Tiny External Components: 1µH/2.2µF or 2.2µH/4.7µF

♦ 28µA Quiescent Current

♦ Factory Preset Outputs from 0.8V to 2.5V

♦ ±1 Initial Accuracy

♦ Low Output Ripple at All Loads

♦ Ultrasonic Skip Mode Down to 1mA Loads

♦ Ultra-Fast Line- and Load-Transient Response

♦ Fast Soft-Start Eliminates Inrush Current

Applications

   Microprocessor/DSP Core Power

   I/O Power

   Cell Phones, PDAs, DSCs, MP3s

   Other Handhelds Where Space Is Limited