GENERAL DESCRIPTION

The CM3718 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 CM3718 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 CM3718 can deliver over 1.5A. The output voltage can be adjusted from VREF to VIN. The input range is from 2.0V to 5.0V. Other features of the CM3718 include high efficiency, low dropout voltage. It is available in a space-saving 8-pin SOP package.

FEATURES

♦ Patent Number #6,452,366

♦ 1.2MHz switching and synchronization

♦ Dynamic output-voltage adjustment from VREF to VIN

♦ 1.5A Guaranteed Output Current

♦ 95 Efficiency

♦ No Schottky Diode Required

♦ External Soft Start

♦ 8-pin PSOP power packages

APPLICATIONS

♦ Cellular Phone

♦ Cordless Phone

♦ PDAs and Handy-Terminals

♦ CPU I/O Supplies

♦ Notebook Chipset Supplies

♦ Battery Operated Devices