General Description

The MAX1623 switch-mode buck regulator with synchronous rectification provides local CPU and bus-termination power in notebook and desktop computers. An internal 55mΩ (typ), 3A PMOS power switch and 60mΩ (typ), 3A NMOS synchronous-rectifier switch deliver continuous load currents up to 3A from a 5V supply with 95 typical efficiency. Output accuracy is ±1, including line and load regulation.

Features

♦ ±1 Output Accuracy, Including Line and Load

Regulation

♦ 94 Efficiency

♦ Internal Switches

55mΩ PMOS Power Switch

60mΩ NMOS Synchronous-Rectifier Switch

♦ Guaranteed 3A Load Capability

♦ Minimal External Components

♦ Pin-Selectable Fixed 3.3V, 2.5V, or

Adjustable (1.1V to 3.8V) Output Voltage

♦ 4.5V to 5.5V Input Voltage Range

♦ 400µA (typ) Supply Current

♦ <1µA Shutdown Supply Current

♦ Constant-Off-Time PWM Operation

♦ Switching Frequencies Up to 350kHz

♦ Idle Mode™ Operation at Light Loads

♦ Thermal Shutdown Protection

♦ Available in 20-Pin SSOP

Applications

5V to 3.3V Conversion

Notebook Computer CPU I/O Supply

Desktop Computer Bus-Termination Supply

CPU Daughter Card Supply

DSP Supply