1. Products
  2. Power Management
  3. Switching Regulators
  4. Flyback, Forward, and Isolated Controller
  5. LTC3873

Alternative Parts


Features and Benefits

  • VIN and VOUT Limited Only by External Components
  • Internal or Programmable External Soft-Start
  • Constant Frequency 200kHz Operation
  • Adjustable Current Limit
  • Current Sense Resistor Optional
  • Maximum 60V on SW Node with RDS(ON) Sensing
  • ±1.5% Voltage Reference Accuracy
  • Current Mode Operation for Excellent Line and Load Transient Response
  • Low Quiescent Current: 300µA
  • Low Profile (1mm) ThinSOT and (0.75mm) 2mm × 3mm DFN Package

Product Details

The LTC3873 is a constant frequency, current mode, boost, flyback or SEPIC DC/DC controller that drives an N-channel power MOSFET in high input and output voltage converter applications. Soft-start can be programmed using an external capacitor.

The LTC3873 provides ±1.5% output voltage accuracy and consumes only 300μA quiescent current during normal operation and only 55μA during micropower start-up. Using a 9.3V internal shunt regulator, the LTC3873 can be powered from a high input voltage through a resistor or it can be powered directly from a low impedance DC voltage of 9V or less.

The LTC3873 is available in 8-lead ThinSOT and 2mm x 3mm DFN packages.


LTC3873 LTC3873-5
VCC UV+ 8.4V 4.1V
VCC UV 4V 2.9V


  • Telecom Power Supplies
  • 42V and 12V Automotive Power Supplies
  • Portable Electronic Equipment

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.

To launch ready-to-run LTspice demonstration circuits for this part:

Step 1: Download and install LTspice on your computer.

Step 2: Click on the link in the section below to download a demonstration circuit.

Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.


Models for the following parts are available in LTspice:


Product Recommendations

LTC3873 Companion Parts

Recommended µModule Regulator

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
LTC3873EDDB#TRMPBF Material Declaration Reliability Data 8-Lead DFN (3mm x 2mm w/ EP)
LTC3873EDDB#TRPBF Material Declaration Reliability Data 8-Lead DFN (3mm x 2mm w/ EP)
LTC3873ETS8#TRMPBF Material Declaration Reliability Data 8-Lead SOT-23
LTC3873ETS8#TRPBF Material Declaration Reliability Data 8-Lead SOT-23
Wafer Fabrication Data R421 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.

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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.