Features and Benefits

  • ±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

Product Details

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.


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

Product Lifecycle icon-recommended Production

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.

Evaluation Kits (1)

Product Recommendations

MAX1623 Companion Parts

Recommended Related Parts

Design Resources

ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well.  "Zero defects" for shipped products is always our goal.

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