1. Products
  2. Power Management
  3. Switching Regulators
  4. Step-Down (Buck) Regulators
  5. Internal Power Switch Buck Regulators
  6. MAX640


Features and Benefits

  • High Efficiency for a Wide Range of Load Currents
  • 10µA Quiescent Current
  • Output Currents Up to 225mA
  • Preset or Adjustable Output Voltage:
    • 5.0V (MAX639)
    • 3.3V (MAX640)
    • 3.0V (MAX653)
  • Low-Battery Detection Comparator
  • Current-Limiting PFM Control Scheme

Product Details

The MAX639/MAX640/MAX653 step-down switching regulators provide high efficiency over a wide range of load currents, delivering up to 225mA. A current-limiting pulse-frequency-modulated (PFM) control scheme gives the devices the benefits of pulse-width-modulated (PWM) converters (high efficiency at heavy loads), while using only 10µA of supply current (vs. 2mA to 10mA for PWM converters). The result is high efficiency over a wide range of loads.

The MAX639/MAX640/MAX653 input range is 4V to 11.5V, and the devices provide lower preset output voltages of 5V, 3.3V, and 3V, respectively. Or, the output can be user-adjusted to any voltage from 1.3V to the input voltage.

The MAX639/MAX640/MAX653 have an internal 1A power MOSFET switch, making them ideal for minimum-component, low- and medium-power applications. For increased output drive capability, use the MAX649/MAX651/MAX652 step-down controllers, which drive an external P-channel FET to deliver up to 5W.


  • 5V to 3.3V Conversion
  • 9V Battery to 5V, 3.3V, or 3V Conversion
  • High-Efficiency Linear Regulator Replacement
  • Portable Instruments and Handy-Terminals

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.

Product Recommendations

MAX640 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.View our quality and reliability program and certifications for more information.

Part Number Material Declaration Reliability Data Pin/Package Drawing CAD Symbols, Footprints & 3D Models
MAX640CPA+ Material Declaration Reliability Data Plastic Dual-In-Line, Narrow (0.3in)
MAX640CSA+ Material Declaration Reliability Data Small-Outline IC, Narrow (0.15in)
MAX640CSA+T Material Declaration Reliability Data Small-Outline IC, Narrow (0.15in)
MAX640ESA+ Material Declaration Reliability Data Small-Outline IC, Narrow (0.15in)
MAX640ESA+T Material Declaration Reliability Data Small-Outline IC, Narrow (0.15in)
Wafer Fabrication Data

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Sample & Buy

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Buy Now Pricing

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List Pricing

(*)The 1Ku list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.


Lead Times

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