1. Products
  2. Power Management
  3. Switching Regulators
  4. SEPIC Regulators
  5. LTC3873-5

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
  • ±1.5% Voltage Reference Accuracy
  • Current Mode Operation for Excellent Line and Load Transient Response
  • 4.1V Undervoltage Threshold for Logic Level
    MOSFET Applications
  • Low Quiescent Current: 300µA
  • Low Profile (1mm) ThinSOT and (0.75mm) 2mm × 3mm DFN Package

Product Details

The LTC3873-5 is a constant frequency current mode controller for boost, flyback or SEPIC DC/DC converters designed to drive an N-channel MOSFET for high input and output voltage converter applications.

The LTC3873-5 provides ±1.5% output voltage accuracy and consumes only 300μA quiescent current during normal operation and only 50μA during micropower start-up. Using a 9.3V internal shunt regulator, the LTC3873-5 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. Soft-start can be programmed using an external capacitor.

The LTC3873-5 is available in 8-lead ThinSOT and 2mm × 3mm DFN packages.


LTC3873 LTC3873-5
VCC UV+ 8.4V 3.9V
VCC UV 4V 2.9V


  • Telecom Power Supplies
  • Automotive Power Supplies
  • PoE Applications

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.

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:


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-5#TRMPBF Material Declaration Reliability Data 8-Lead DFN (3mm x 2mm w/ EP)
LTC3873EDDB-5#TRPBF Material Declaration Reliability Data 8-Lead DFN (3mm x 2mm w/ EP)
LTC3873ETS8-5#TRMPBF Material Declaration Reliability Data 8-Lead SOT-23
LTC3873ETS8-5#TRPBF Material Declaration Reliability Data 8-Lead SOT-23
LTC3873IDDB-5#TRMPBF Material Declaration Reliability Data 8-Lead DFN (3mm x 2mm w/ EP)
LTC3873IDDB-5#TRPBF Material Declaration Reliability Data 8-Lead DFN (3mm x 2mm w/ EP)
LTC3873ITS8-5#TRMPBF Material Declaration Reliability Data 8-Lead SOT-23
LTC3873ITS8-5#TRPBF Material Declaration Reliability Data 8-Lead SOT-23
Wafer Fabrication Data R421 Reliability Data

Sample & Buy

Ordering FAQs

See our Ordering FAQs for answers to questions about online orders, payment options and more.


Buy Now Pricing

(**) Displayed Buy Now Price and Price Range is based on small quantity orders.


List Pricing

(*)The 1Ku 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. authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.


Lead Times

Please see the latest communication from our CCO regarding lead times.



A Sample link will be shown above, next to the part, only for parts that are included in our sample program. Selecting the Sample button will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.

Price Table Help