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