1. Products
  2. Power Management
  3. Switching Regulators
  4. Step-Down (Buck) Regulators
  5. Micropower Buck Regulators
  6. LTC3447


Features and Benefits

  • I2C Programmable Output with 21.6mV Resolution
  • Overtemperature Protected
  • High Efficiency: Up to 93%
  • Very Low Quiescent Current: Only 33µA
  • 600mA Output Current at VIN = 3V
  • 2.5V to 5.5V Input Voltage Range
  • 1MHz Constant Frequency Operation
  • No Schottky Diode Required
  • Low Dropout Operation: 100% Duty Cycle
  • Stable with Ceramic Capacitors
  • Shutdown Mode Draws <1µA Supply Current
  • ±2% Output Voltage Accuracy
  • Standard (100kHz) or Fast Mode (400kHz) I2C
  • 6-Bit Voltage DAC (0.69V to 2.05V)
  • Disable Burst Mode Operation
  • Enable Power Good Blanking
  • Optional External Start-Up Resistors
  • Soft-Start
  • 10 Lead, 3mm × 3mm DFN Package

Product Details

The LTC3447 is a high efficiency monolithic synchronous current mode buck regulator. Using an I2C interface, the output voltage can be set between 0.69V and 2.05V using an internal 6-bit DAC.

The buck regulator has optional external feedback resistors that can be used for setting the initial start up voltage. The feedback voltage reference for this start-up option is 0.6V. Once the voltage DAC is updated via the I2C, the buck regulator switches from external to internal feedback resistors. When there are no external resistors, the default start-up voltage is 1.38V.

The switching frequency is internally set at 1MHz, allowing the use of small surface mount inductors and capacitors.

In Burst Mode® operation, supply current is only 33µA, dropping to <1µA in shutdown. The 2.5V to 5.5V input voltage range makes the LTC3447 ideally suited for single cell Li-Ion battery-powered applications. 100% duty cycle capability provides low dropout operation, extending battery life in portable systems. Automatic Burst Mode operation increases efficiency at light loads, further extending battery life.

The internal synchronous switch increases efficiency and eliminates the need for an external Schottky diode.

Protected by U.S. Patents, including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131.


  • Distributed Power Supplies
  • Notebook Computers
  • PDAs and Other Handheld Devices

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

LTC3447 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
LTC3447EDD#PBF Material Declaration Reliability Data 10-Lead DFN (3mm x 3mm w/ EP)
LTC3447EDD#TRPBF Material Declaration Reliability Data 10-Lead DFN (3mm x 3mm w/ EP)
Wafer Fabrication Data R415 Reliability Data

Sample & Buy

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Buy Now Pricing

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List Pricing

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Lead Times

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Evaluation Boards

Pricing displayed is based on 1-piece.

Up to two boards can be purchased through Analog.com. To order more than two, please purchase through one of our listed distributors.

Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.