LTC3129 - 15V, 200mA Synchronous Buck-Boost DC/DC Converter with 1.3μA Quiescent Current


  • Regulates VOUT Above, Below or Equal to VIN
  • Wide VIN Range: 2.42V to 15V, 1.92V to 15V After Start-Up (Bootstrapped)
  • Wide VOUT Range: 1.4V to 15.75V
  • 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

Typical Application

LTC3129 Typical Application
LTC3129 Typical Application


The LTC®3129 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 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.

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

The LTC3129 is available in thermally enhanced 3mm × 3mm QFN and 16-lead MSOP packages. For fixed output voltage options, see the functionally equivalent LTC3129-1, which eliminates the need for an external feedback divider.

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


CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
LTC3129EMSE#PBF MS-16E MSE E 05-08-1667 Yes
LTC3129EMSE#TRPBF MS-16E MSE E 05-08-1667 Yes
LTC3129EUD#PBF 3x3 QFN-16 UD E 05-08-1700 Yes
LTC3129EUD#TRPBF 3x3 QFN-16 UD E 05-08-1700 Yes
LTC3129IMSE-1#PBF MS-16E MSE I 05-08-1667 Yes
LTC3129IMSE#PBF MS-16E MSE I 05-08-1667 Yes
LTC3129IMSE#TRPBF MS-16E MSE I 05-08-1667 Yes
LTC3129IUD#PBF 3x3 QFN-16 UD I 05-08-1700 Yes
LTC3129IUD#TRPBF 3x3 QFN-16 UD I 05-08-1700 Yes

LTC3129 Package Drawing
LTC3129 Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
LTC3129EMSE#PBF MS-16E E $4.22 $2.95 Yes
LTC3129EMSE#TRPBF MS-16E E $3.01 Yes
LTC3129EUD#PBF 3x3 QFN-16 E $4.22 $2.95 Yes
LTC3129EUD#TRPBF 3x3 QFN-16 E $4.28 $3.01 Yes
LTC3129IMSE-1#PBF MS-16E I $4.64 $3.25 Yes
LTC3129IMSE#PBF MS-16E I $4.64 $3.25 Yes
LTC3129IMSE#TRPBF MS-16E I $3.31 Yes
LTC3129IUD#PBF 3x3 QFN-16 I $4.64 $3.25 Yes
LTC3129IUD#TRPBF 3x3 QFN-16 I $3.31 Yes
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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 Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Part Number Description Price Documentation
DC1922A LTC3129 Demo Board | Micropower, Sync Buck-Boost, 2.42V ≤ VIN ≤ 15V, Vout = 5V @ 200mA $125.00
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Design Tools


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