1. Products
  2. Power Management
  3. Switching Regulators
  4. Step-Down (Buck) Regulators
  5. Internal Power Switch Buck Regulators
  6. MAX8643A


Features and Benefits

  • Internal 37mΩ RDSON MOSFETs
  • Continuous 3A Output Current
  • ±1% Output Accuracy Over Load, Line, and Temperature
  • Operates from 2.35V to 3.6V Supply
  • Adjustable Output from 0.6V to (0.9 x VIN)
  • Soft-Start Reduces Inrush Supply Current
  • 500kHz to 2MHz Adjustable Switching Frequency
  • Compatible with Ceramic, Polymer, and Electrolytic Output Capacitors
  • VID-Selectable Output Voltages
    • 0.6, 0.7, 0.8, 1.0, 1.2, 1.5, 1.8, 2.0, and 2.5V
  • Fully Protected Against Overcurrent and Overtemperature
  • Safe-Start into Prebiased Output
  • Sink/Source Current in DDR Applications
  • Lead-Free, 24-Pin, 4mm x 4mm Thin QFN Package

Product Details

The MAX8643A high-efficiency switching regulator delivers up to 3A load current at output voltages from 0.6V to (0.9 x VIN). The IC operates from 2.35V to 3.6V, making it ideal for on-board point-of-load and postregulation applications. Total output error is less than ±1% over load, line, and temperature.

The MAX8643A features fixed-frequency PWM mode operation with a switching frequency range of 500kHz to 2MHz set by an external resistor. High-frequency operation allows for an all ceramic capacitor design. The high operating frequency also allows for small-size external components.

The low-resistance on-chip nMOS switches ensure high efficiency at heavy loads while minimizing critical inductances, making the layout a much simpler task with respect to discrete solutions. Following a simple layout and footprint ensures first-pass success in new designs.

The MAX8643A comes with a high-bandwidth (> 14MHz) voltage-error amplifier. The voltage-mode control architecture and the voltage-error amplifier permit a type III compensation scheme to be utilized to achieve maximum loop bandwidth, up to 20% of the switching frequency. High loop bandwidth provides fast transient response, resulting in less required output capacitance and allowing for all-ceramic capacitor designs.

The MAX8643A provides two three-state logic inputs to select one of nine preset output voltages. The preset output voltages allow customers to achieve ±1% output-voltage accuracy without using expensive 0.1% resistors. In addition, the output voltage can be set to any customer value by either using two external resistors at the feedback with 0.6V internal reference or applying an external reference voltage to the REFIN input. The MAX8643A offers programmable soft-start time using one capacitor to reduce input inrush current. The MAX8643A is available in a lead-free, 24-pin, 4mm x 4mm thin QFN package.


  • ASIC/CPU/DSP Core and I/O Voltages
  • Base-Station Power Supplies
  • DDR Power Supplies
  • POLs
  • RAID Control Power Supplies
  • Telecom and Networking Power Supplies

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

MAX8643A Companion 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
MAX8643AETG+ Material Declaration Reliability Data 24-LFCSP-4X4X0.75
MAX8643AETG+T Material Declaration Reliability Data 24-LFCSP-4X4X0.75
MAX8643AETG/V+ Material Declaration Reliability Data 24-LFCSP-4X4X0.75
MAX8643AETG/V+T Material Declaration Reliability Data 24-LFCSP-4X4X0.75
Wafer Fabrication Data MAX8643A Reliability Data

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