General Description

The MAX1705/MAX1706 are high-efficiency, low-noise, step-up DC-DC converters with an auxiliary linearregulator output. These devices are intended for use in battery-powered wireless applications. They use a synchronous rectifier pulse-width-modulation (PWM) boost topology to generate 2.5V to 5.5V outputs from battery inputs, such as 1 to 3 NiCd/NiMH cells or 1 Li-Ion cell. The MAX1705 has an internal 1A n-channel MOSFET switch. The MAX1706 has a 0.5A switch. Both devices also have a built-in low-dropout linear regulator that delivers up to 200mA.

特性 Features

? Up to 96 Efficiency

? 1.1VIN Guaranteed Startup

? Up to 850mA Output (MAX1705)

? Step-Up Output (2.5V to 5.5V Adjustable)

? Linear Regulator (1.25V to 5.0V Adjustable)

? PWM/PFM Synchronous-Rectified Topology

? 300kHz PWM Mode or Synchronizable

? 1μA Shutdown Mode

? Voltage Monitor

? Pushbutton On/Off Control

Applications

Digital Cordless Phones

PCS Phones

Personal Communicators

Wireless Handsets

Palmtop Computers

Two-Way Pagers

Handheld Instruments