LTC3118 - 18V, 2A Buck-Boost DC/DC Converter with Low-Loss Dual Input PowerPath


  • Integrated High Efficiency Dual Input PowerPath™ Plus Buck-Boost DC/DC Converter
  • Ideal Diode or Priority VIN Select Modes
  • VIN1 and VIN2 Range: 2.2V to 18V
  • VOUT Range: 2V to 18V
  • Either VIN Can Be Above, Below or Equal to VOUT
  • Generates 5V at 2A for VIN > 6V
  • 1.2MHz Low Noise Fixed Frequency Operation
  • Current Mode Control
  • All Internal N-Channel MOSFETs
  • Pin-Selectable PWM or Burst Mode® Operation
  • Accurate, Independent RUN Pin Thresholds
  • Up to 94% Efficiency
  • VIN and VOUT Power Good Indicators
  • IQ of 50μA in Sleep, 2μA in Shutdown
  • 4mm × 5mm 24-Lead QFN or 28-Lead TSSOP Packages

Typical Application

LTC3118 Typical Application
LTC3118 Typical Application


The LTC®3118 is a dual-input, wide voltage range synchronous buck-boost DC/DC converter with an intelligent, integrated, low loss PowerPath control. The unique power switch architecture provides efficient operation from either input source to a programmable output voltage above, below or equal to the input. Voltage capability of up to 18V provides flexibility and voltage margin for a wide variety of applications and power sources.

The LTC3118 uses a low noise, current mode architecture with a fixed 1.2MHz PWM mode frequency that minimizes the solution footprint. For high efficiency at light loads, automatic Burst Mode operation can be selected consuming only 50μA of quiescent current in sleep.

System level features include ideal diode or VIN priority modes, VIN and VOUT power good indicators, accurate RUN comparators to program independent UVLO thresholds, and output disconnect in shutdown. Other features include 2μA shutdown current, short-circuit protection, soft-start, current limit and thermal overload protection.

The LTC3118 is offered in thermally enhanced 24-lead 4mm × 5mm QFN and 28-lead TSSOP 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
LTC3118EFE#PBF TSSOP-28 FE E 05-08-1663 (EB) Yes
LTC3118EFE#TRPBF TSSOP-28 FE E 05-08-1663 (EB) Yes
LTC3118EUFD#PBF 4x5 QFN-24 UFD E 05-08-1696 Yes
LTC3118EUFD#TRPBF 4x5 QFN-24 UFD E 05-08-1696 Yes
LTC3118HFE#PBF TSSOP-28 FE H 05-08-1663 (EB) Yes
LTC3118HFE#TRPBF TSSOP-28 FE H 05-08-1663 (EB) Yes
LTC3118HUFD#PBF 4x5 QFN-24 UFD H 05-08-1696 Yes
LTC3118HUFD#TRPBF 4x5 QFN-24 UFD H 05-08-1696 Yes
LTC3118IFE#PBF TSSOP-28 FE I 05-08-1663 (EB) Yes
LTC3118IFE#TRPBF TSSOP-28 FE I 05-08-1663 (EB) Yes
LTC3118IUFD#PBF 4x5 QFN-24 UFD I 05-08-1696 Yes
LTC3118IUFD#TRPBF 4x5 QFN-24 UFD I 05-08-1696 Yes
LTC3118MPFE#PBF TSSOP-28 FE MP 05-08-1663 (EB) Yes
LTC3118MPFE#TRPBF TSSOP-28 FE MP 05-08-1663 (EB) Yes
LTC3118MPUFD#PBF 4x5 QFN-24 UFD MP 05-08-1696 Yes
LTC3118MPUFD#TRPBF 4x5 QFN-24 UFD MP 05-08-1696 Yes

LTC3118 Package Drawing
LTC3118 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
LTC3118EFE#PBF TSSOP-28 E $8.57 $6.00 Yes
LTC3118EFE#TRPBF TSSOP-28 E $6.06 Yes
LTC3118EUFD#PBF 4x5 QFN-24 E $8.22 $5.75 Yes
LTC3118EUFD#TRPBF 4x5 QFN-24 E $5.81 Yes
LTC3118HFE#PBF TSSOP-28 H $9.79 $6.85 Yes
LTC3118HFE#TRPBF TSSOP-28 H $6.91 Yes
LTC3118HUFD#PBF 4x5 QFN-24 H $9.40 $6.58 Yes
LTC3118HUFD#TRPBF 4x5 QFN-24 H $6.64 Yes
LTC3118IFE#PBF TSSOP-28 I $9.43 $6.60 Yes
LTC3118IFE#TRPBF TSSOP-28 I $6.66 Yes
LTC3118IUFD#PBF 4x5 QFN-24 I $9.04 $6.33 Yes
LTC3118IUFD#TRPBF 4x5 QFN-24 I $6.39 Yes
LTC3118MPFE#PBF TSSOP-28 MP $25.46 $17.82 Yes
LTC3118MPFE#TRPBF TSSOP-28 MP $17.88 Yes
LTC3118MPUFD#PBF 4x5 QFN-24 MP $24.40 $17.08 Yes
LTC3118MPUFD#TRPBF 4x5 QFN-24 MP $17.14 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
DC2045A LTC3118EUFD Demo Board | Dual Input Buck-Boost, 2.5V ≤ VIN ≤ 18V, Vout = 5V @ up to 2A $175.00
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Click here to view our complete list of demo boards


  • Systems with Multiple Input Sources
  • Back Up Power Systems
  • Wall Adapter or Li-Ion(s) Input to 5VOUT
  • Battery or Super Capacitor Input for Reserve Power
  • Replace Diode-OR Designs with Higher Efficiency, Flexibility and Performance

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Design Tools


LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

Models for the following parts are available in LTspice:


The LTpowerCAD design tool is a complete power supply design tool program that can significantly ease the tasks of power supply design. It guides users to a solution, selects power stage components, provides detailed power efficiency, shows quick loop bode plot stability and load transient analysis, and can export a final design to LTspice for simulation. Click here to download LTpowerCAD

To open the project file for this circuit:

  • Step 1: If you have not installed LTpowerCAD on this computer, download and install LTpowerCAD
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Design tools for the following parts are available in LTpowerCAD:

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