LTC3127 - 1A Buck-Boost DC/DC Converter with Programmable Input Current Limit


  • Programmable (0.2A to 1A) ±4% Accurate Average Input Current Limit
  • Regulated Output with Input Voltages Above, Below or Equal to the Output
  • 1.8V to 5.5V (Input) and 1.8V to 5.25V (Output) Voltage Range
  • 0.6A Continuous Output Current: VIN > 1.8V
  • 1A Continuous Output Current: VIN > 3V
  • Single Inductor
  • Synchronous Rectification: Up to 96% Efficiency
  • Burst Mode® Operation: IQ = 35μA (Pin Selectable)
  • Output Disconnect in Shutdown
  • <1μA Shutdown Current
  • Small, Thermally Enhanced 10-Lead (3mm × 3mm × 0.75mm) DFN and 12-Lead MSOP Packages

Typical Application

LTC3127 Typical Application
LTC3127 Typical Application


The LTC3127 is a wide VIN range, highly efficient, 1.35MHz fixed frequency buck-boost DC/DC converter that operates from input voltages above, below or equal to the output voltage. The LTC3127 features programmable average input current limit, making it ideal for power-limited input sources. The input current limit is programmed with a single resistor and is accurate from 0.2A to 1A of average input current.

The topology incorporated provides a continuous transfer function through all operating modes. Other features include <1μA shutdown current, pin-selectable Burst Mode operation and thermal overload protection. The LTC3127 is housed in thermally enhanced 10-lead (3mm × 3mm × 0.75mm) DFN packages and 12-lead MSOP packages.


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
LTC3127EDD#PBF 3x3 DFN-10 DD E 05-08-1699 Yes
LTC3127EDD#TRPBF 3x3 DFN-10 DD E 05-08-1699 Yes
LTC3127EMSE#PBF MS-12E MSE E 05-08-1666 Yes
LTC3127EMSE#TRPBF MS-12E MSE E 05-08-1666 Yes

LTC3127 Package Drawing
LTC3127 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
LTC3127EDD#PBF 3x3 DFN-10 E $4.22 $2.95 Yes
LTC3127EDD#TRPBF 3x3 DFN-10 E $3.01 Yes
LTC3127EMSE#PBF MS-12E E $4.29 $3.00 Yes
LTC3127EMSE#TRPBF MS-12E E $3.06 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
DC1451A LTC3127EDD Demo Board | Prog Average Input Current Limit, 1.2MHz, 1.8V ≤ VIN ≤ 5.5V, Vout = 3.8V @ 2A Pulsed $100.00
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