LTC3119 - 18V, 5A Synchronous Buck-Boost DC/DC Converter


  • Input Voltage Range: 2.5V to 18V
  • Runs Down to VIN = 250mV After Start-Up
  • Output Voltage Range: 0.8V to 18V
  • 5A Output Current in Buck Mode, VIN > 6V
  • 3A Output Current for VIN = 3.6V, VOUT = 5V
  • Programmable Switching Frequency: 400kHz to 2MHz
  • Synchronizable with an External Clock Up to 2MHz
  • Accurate Run Comparator Threshold
  • Burst Mode® Operation, No-Load IQ = 35μA
  • Ultralow Noise Buck-Boost PWM
  • Current Mode Control
  • Maximum Power Point Control
  • Power Good Indicator
  • Internal Soft-Start
  • 28-Lead 4mm × 5mm QFN and TSSOP Packages

Typical Application

LTC3119 Typical Application
LTC3119 Typical Application


The LTC®3119 is a high efficiency 18V monolithic buck-boost converter that can deliver up to 5A of continuous output current. Extensive feature integration and very low resistance internal power switches minimize the total solution footprint for even the most demanding applications. A proprietary 4-switch PWM architecture provides seamless low noise operation from input voltages above, equal to, or below the output voltage.

External frequency programming as well as synchronization using an internal PLL enable operation over a wide switching frequency range of 400kHz to 2MHz. The wide 2.5V to 18V input range is well suited for operation from unregulated power sources including battery stacks and backup capacitors. After start-up, operation is possible with input voltages as low as 250mV.

Other features include: output short-circuit protection, thermal overload protection, less than 3μA shutdown current, power good indicator, Burst Mode operation, and maximum power point control.

The LTC3119 is offered in thermally enhanced 28-lead 4mm × 5mm QFN and TSSOP packages.


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

Part Number Package Code Temp Package
LTC3119EFE#PBF TSSOP-28 FE E 05-08-1663 (EA) Yes
LTC3119EFE#TRPBF TSSOP-28 FE E 05-08-1663 (EA) Yes
LTC3119EUFD#PBF 4x5 QFN-28 UFD E 05-08-1712 Yes
LTC3119EUFD#TRPBF 4x5 QFN-28 UFD E 05-08-1712 Yes
LTC3119HFE#PBF TSSOP-28 FE H 05-08-1663 (EA) Yes
LTC3119HFE#TRPBF TSSOP-28 FE H 05-08-1663 (EA) Yes
LTC3119IFE#PBF TSSOP-28 FE I 05-08-1663 (EA) Yes
LTC3119IFE#TRPBF TSSOP-28 FE I 05-08-1663 (EA) Yes
LTC3119IUFD#PBF 4x5 QFN-28 UFD I 05-08-1712 Yes
LTC3119IUFD#TRPBF 4x5 QFN-28 UFD I 05-08-1712 Yes
LTC3119MPFE#PBF TSSOP-28 FE MP 05-08-1663 (EA) Yes
LTC3119MPFE#TRPBF TSSOP-28 FE MP 05-08-1663 (EA) Yes

LTC3119 Package Drawing
LTC3119 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
LTC3119EFE#PBF TSSOP-28 E $10.50 $7.35 Yes
LTC3119EFE#TRPBF TSSOP-28 E $10.56 $7.41 Yes
LTC3119EUFD#PBF 4x5 QFN-28 E $10.22 $7.15 Yes
LTC3119EUFD#TRPBF 4x5 QFN-28 E $10.28 $7.21 Yes
LTC3119HFE#PBF TSSOP-28 H $11.43 $8.00 Yes
LTC3119HFE#TRPBF TSSOP-28 H $11.49 $8.06 Yes
LTC3119IFE#PBF TSSOP-28 I $11.00 $7.70 Yes
LTC3119IFE#TRPBF TSSOP-28 I $11.06 $7.76 Yes
LTC3119IUFD#PBF 4x5 QFN-28 I $10.64 $7.45 Yes
LTC3119IUFD#TRPBF 4x5 QFN-28 I $10.70 $7.51 Yes
LTC3119MPFE#PBF TSSOP-28 MP $28.36 $19.85 Yes
LTC3119MPFE#TRPBF TSSOP-28 MP $28.42 $19.91 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
DC2129A LTC3119 Demo Board | Sync Buck-Boost, 2.5V ≤ VIN ≤ 18V, VOUT = 5V @ Up to 5A $225.00
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