General Description

The MAX1684/MAX1685 are high-efficiency, internal switch, pulse-width modulation (PWM) step-down switching regulators intended to power cellular phones, communicating PDAs, and handy-terminals. These devices deliver a guaranteed 1A output current from two lithium-ion (Li+) batteries. Their wide-input voltage range of 2.7V to 14V gives design flexibility and allows batteries to charge from a wall cube, since the ICs operate at the higher voltages that occur when the battery is removed. The output voltage is preset to 3.3V or can be externally adjusted from 1.25V to VIN.

Features

♦ Up to 96 Efficiency

♦ 1A Guaranteed Output Current

♦ 100 Duty Cycle in Dropout

♦ 2.7V to 14V Input Range (15V Absolute Max)

♦ ±1 Accurate Reference Output

♦ 0.24Ω P-Channel On-Resistance

♦ Synchronizable Switching Frequency

♦ Fixed-Frequency PWM Operation

300kHz (MAX1684)

600kHz (MAX1685)

♦ 150µA Normal-Mode Quiescent Current

♦ 25µA Low-Power Mode Quiescent Current

♦ 2µA Shutdown Current

♦ Dual Mode™ Fixed 3.3V (±1) Output or Adjustable Output (1.25V to VIN)

♦ Small 16-QSOP Package

♦ Auxiliary Output (CVL): 3V/5mA

Applications

Cellular Phones

Two-Way Radios and Walkie-Talkies

Computer Peripherals

Personal Communicators

PDAs and Handy-Terminals