Features and Benefits

  • High Efficiency (Up to 96%) Dual Step-Down Outputs
  • 300mA Output Current per Channel at VIN = 3V
  • 2.25MHz Constant-Frequency Operation
  • 2.5V to 5.5V Input Voltage Range
  • Low Dropout Operation: 100% Duty Cycle
  • No Schottky Diodes Required
  • Internally Compensated for All Ceramic Capacitors
  • Independent Internal Soft-Start for Each Channel
  • Available in Fixed Output Versions
  • Current Mode Operation for Excellent Line and Load Transient Response
  • 0.6V Reference Allows Low Output Voltages
  • Short-Circuit Protected
  • Ultralow Shutdown Current: IQ < 1µA
  • Low Profile (0.75mm) 8-Lead 3mm × 2mm DFN Package

Product Details

The LTC3547B is a dual, 2.25MHz, constant-frequency, synchronous step-down DC/DC converter in a tiny 3mm × 2mm DFN package. 100% duty cycle provides low dropout operation, extending battery life in portable systems. Low output voltages are supported with the 0.6V feedback reference voltage. Each regulator can supply 300mA continuous output current.

The input voltage range is 2.5V to 5.5V, making it ideal for Li-Ion polymer and USB powered applications. Supply current is only 1µA in shutdown.

An internally set 2.25MHz switching frequency allows the use of tiny surface mount inductors and capacitors. Internal soft-start reduces inrush current during start-up. All outputs are internally compensated to work with ceramic capacitors. The LTC3547B is available in a low profile (0.75mm) 3mm × 2mm DFN package. The LTC3547B is also available in a fixed output voltage configuration selected via internal resistor dividers.


  • Cellular Telephones
  • Digital Still Cameras
  • Wireless and DSL Modems
  • Portable Media Players
  • PDAs/Palmtop PCs

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)

Tools & Simulations


LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.


Models for the following parts are available in LTspice:



LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.


Design tools for the following parts are available in LTpowerCAD:


Product Recommendations

LTC3547B 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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The USA 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. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.

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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.