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3A, Low-Voltage, Step-Down Regulator with Synchronous Rectification and Internal Switches

Industry's Smallest 3A DC-DC with Synchronous Rectifier

Product Details

Key Features

Parametric specs for Step-Down Switching Regulators
VIN (V) (min) 4.5
VIN (V) (max) 5.5
VOUT1 (V) (min) 1.1
VOUT1 (V) (max) 3.8
IOUT1 (A) (max) 3
Switch Type Internal
Preset VOUT (V) 2.5
3.3
Output Adjust. Method Preset
Resistor
Synchronous Switching? Yes
# DC-DC Outputs 1
Switching Frequency (kHz) 350
Package/Pins SSOP/20
Budgetary
Price (See Notes)
6.57
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Simplified Block Diagram

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Parameters

Parametric specs for Step-Down Switching Regulators
VIN (V) (min) 4.5
VIN (V) (max) 5.5
VOUT1 (V) (min) 1.1
VOUT1 (V) (max) 3.8
IOUT1 (A) (max) 3
Switch Type Internal
Preset VOUT (V) 2.5
3.3
Output Adjust. Method Preset
Resistor
Synchronous Switching? Yes
# DC-DC Outputs 1
Switching Frequency (kHz) 350
Package/Pins SSOP/20
Budgetary
Price (See Notes)
6.57

Key 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/Uses

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

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.

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.

Simplified Block Diagram

MAX1623: Typical Operating Circuit MAX1623: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .