General Description

The MAX1775 is a dual, step-down DC-DC converter that generates both the main (+3.3V at over 2A) and core (+1.8V at up to 1.5A) supplies for a complete power solution for PDAs, subnotebooks, and other hand-held devices. The main output is adjustable from +1.25V to +5.5V. The core output is adjustable from 1V to 5V. Both switching converters operate at up to 1.25MHz for small external components and use synchronous rectifiers to achieve efficiencies up to 95. Operation with up to 100 duty cycle provides the lowest possible dropout voltage to extend useful battery life.

Features

♦ Dual, High-Efficiency, Synchronous Rectified Step-Down Converter

♦ Main Power

Adjustable from +1.25V to +5.5V

Over 2A Load Current

Up to 95 Efficiency

♦ Core Power

Adjustable from 1V to 5V

Internal Switches

Up to 1.5A Load Current

Up to 92 Efficiency

♦ 100 (max) Duty Cycle

♦ Up to 1.25MHz Switching Frequency

♦ Input Voltage Range from +2.7V to +28V

♦ 170µA Quiescent Current

♦ 5µA Shutdown Current

♦ Digital Soft-Start

♦ Independent Shutdown Inputs