Features and Benefits

  • 600mA Output Current
  • 2.5V to 5.5V Input Voltage Range
  • 2.25MHz Constant-Frequency Operation, Spread Spectrum or Synchronized PLL (1MHz to 3MHz)
  • High Efficiency: Up to 95%
  • 1A Peak Inductor Current
  • Very Low Quiescent Current: Only 45µA During Burst Mode Operation
  • No Schottky Diode Required
  • Low Dropout Operation: 100% Duty Cycle
  • Overtemperature Protected
  • Stable with Ceramic Capacitors
  • Shutdown Mode Draws <1µA Supply Current
  • ±2% Output Voltage Accuracy
  • Current Mode Operation for Excellent Line and Load Transient Response
  • Soft-Start
  • Available in a Low Profi le (0.75mm) 2mm × 3mm 6-Lead DFN Package

Product Details

The LTC3543 is a high efficiency monolithic synchronous current mode buck regulator.

The switching frequency is internally set at 2.25MHz, allowing the use of small surface mount inductors and capacitors. In PLL mode, the LTC3543 can acquire frequencies between 1MHz and 3MHz. Also, the LTC3543 has spread spectrum capability providing a lower noise regulated output, as well as low noise at the input.

In Burst Mode® operation, the supply current is only 45µA, dropping to <1µA in shutdown. The 2.5V to 5.5V input voltage range makes the LTC3543 ideally suited for single Li-Ion battery-powered applications. The 100% duty cycle provides a low dropout operation, extending the battery life in portable systems. 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.


  • Portable Instruments
  • Cellular Phones

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:


Product Recommendations

LTC3543 Companion Parts

Recommended Related Parts

Recommended Suggested Oscillator

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.

Sample & Buy

Sample & Buy functionality exists in desktop site
Check Inventory

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.

Price Table Help

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.