Analog Devices MAX1623 Product Info

• ±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

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.

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.

Applications

• 5V to 3.3V Conversion
• CPU Daughter Card Supply
• Desktop Computer Bus-Termination Supply
• DSP Supply
• Notebook Computer CPU I/O Supply