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  2. Power Management
  3. Switching Regulators
  4. Buck-Boost Regulators
  5. Internal Power Switch Buck-Boost Regulators
  6. LTC3129-1


Features and Benefits

  • Regulates VOUT Above, Below or Equal to VIN
  • Wide VIN Range: 2.42V to 15V, 1.92V to 15V After Start-Up (Bootstrapped)
  • Fixed Output Voltage with Eight User-Selectable Settings from 2.5V to 15V
  • 200mA Output Current in Buck Mode
  • Single Inductor
  • 1.3μA Quiescent Current
  • Programmable Maximum Power Point Control
  • 1.2MHz Ultralow Noise PWM
  • Current Mode Control
  • Pin Selectable Burst Mode® Operation
  • Up to 95% Efficiency
  • Accurate RUN Pin Threshold
  • Power Good Indicator
  • 10nA Shutdown Current
  • Thermally Enhanced 3mm × 3mm QFN and 16-Lead MSOP Packages

Product Details

The LTC3129-1 is a high efficiency, 200mA buck-boost DC/DC converter with a wide VIN and VOUT range. It includes an accurate RUN pin threshold to allow predictable regulator turn-on and a maximum power point control (MPPC) capability that ensures maximum power extraction from non-ideal power sources such as photovoltaic panels.

The LTC3129-1 employs an ultralow noise, 1.2MHz PWM switching architecture that minimizes solution footprint by allowing the use of tiny, low profile inductors and ceramic capacitors. Built-in loop compensation and soft-start simplify the design. For high efficiency operation at light loads, automatic Burst Mode operation can be selected, reducing the quiescent current to just 1.3μA. To further reduce part count and improve light load efficiency, the LTC3129-1 includes an internal voltage divider to provide eight selectable fixed output voltages.

Additional features include a power good output, less than 10nA of shutdown current and thermal shutdown.

The LTC3129-1 is available in thermally enhanced 3mm × 3mm QFN and 16-lead MSOP packages. For an adjustable output voltage, see the functionally equivalent LTC3129.

Output Voltage
LTC3129 Adjustable 1.4V to 15.75V via resistor divider
LTC3129-1 8 pin programmable output voltages from 2.5V to 15V


  • Industrial Wireless Sensor Nodes
  • Post-Regulator for Harvested Energy
  • Solar Panel Post-Regulator/Charger
  • Intrinsically Safe Power Supplies
  • Wireless Microphones
  • Avionics-Grade Wireless Headsets

Product Lifecycle icon-recommended Recommended for New Designs

This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.

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

LTC3129-1 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
LTC3129EMSE-1#PBF Material Declaration Reliability Data 16-Lead MSOP w/ EP
LTC3129EMSE-1#TRPBF Material Declaration Reliability Data 16-Lead MSOP w/ EP
LTC3129EUD-1#PBF Material Declaration Reliability Data 16-Lead QFN (3mm x 3mm x 0.75mm w/ EP)
LTC3129EUD-1#TRPBF Material Declaration Reliability Data 16-Lead QFN (3mm x 3mm x 0.75mm w/ EP)
LTC3129IMSE-1#TRPBF Material Declaration Reliability Data 16-Lead MSOP w/ EP
LTC3129IUD-1#PBF Material Declaration Reliability Data 16-Lead QFN (3mm x 3mm x 0.75mm w/ EP)
LTC3129IUD-1#TRPBF Material Declaration Reliability Data 16-Lead QFN (3mm x 3mm x 0.75mm w/ EP)
Wafer Fabrication Data R526 Reliability Data

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Sample & Buy

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Lead Times

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Evaluation Boards

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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.