GENERAL DESCRIPTION

The CM3708A is a low-noise, pulse-width-modulated (PWM), DC-DC step-down converter. It powers logic and transmitters in small wireless systems such as cellular phones, communicating PDAs, and handy-terminals. The device features an internal synchronous rectifier for high efficiency; it requires no external Schottky diode. Excellent noise characteristics and fixed-frequency operation provide easy post-filtering. The CM3708A is ideally suited for Li-lon battery applications. It is also useful for +3V or +5V fixed input applications.

The device operates in one of four modes. Forced PWM mode operates at a fixed frequency regardless of the load. Shutdown mode places the device in standby, reducing quiescent supply current to under 0.1μA.

The CM3708A can deliver over 3.0A. The output voltage can be adjusted from VREF to VIN. The input range is from 2.0V to 5.5V. Other features of the CM3708A include high efficiency, low dropout voltage. It is available in a space-saving 16-pin SOP & TSSOP package.

FEATURES

♦ Patent Filed #6,452,366

♦ 600KHz switching and synchronization

♦ Dynamic output-voltage adjustment from VREF to VIN

♦ 3A Guaranteed Output Current

♦ 95% Efficiency

♦ No Schottky Diode Required

♦ 16-pin PSOP/PTSSOP power packages

♦ 6A Low Noise Current Limit Protection

♦ External Soft Start

♦ Rail to Rail output Buck Converter

APPLICATIONS

♦ Cellular Phone

♦ Cordless Phone

♦ PDAs and Handy-Terminals

♦ AGP Chipset Supplies

♦ CPU I/O Supplies

♦ Notebook Chipset Supplies

♦ Battery Operated Devices