Conv DC-DC Single Step Down 4.5V to 5.5V 20-Pin SSOP T/R

The MAX1623 switch-mode buck regulator with synchronous rectification provides local CPU and bus-termination power in notebook and desktop computers. An internal 55mO (typ), 3A PMOS power switch and 60mO (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. The MAX1623 features constant-off-time, current-mode pulse-width-modulation (PWM) control with switching frequencies as high as 350kHz. An external resistor at the TOFF pin sets the off-time, allowing optimum design flexibility in terms of switching frequency, output switching noise, and inductor size. This device is available in a space-saving 20-pin SSOP package.

• ±1% Output Accuracy, Including Line and Load Regulation
• 94% Efficiency
• Internal Switches
  • 55mO PMOS Power Switch
  • 60mO 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