LT3798 - Isolated No Opto-Coupler Flyback Controller with Active PFC


  • Isolated PFC Flyback with Minimum Number of External Components
  • VIN and VOUT Limited Only by External Components
  • Active Power Factor Correction
  • Low Harmonic Distortion
  • No Opto-Coupler Required
  • Constant-Current and Constant-Voltage Regulation
  • Accurate Regulated Voltage and Current (±5% Typical)
  • Energy Star Compliant (<0.5W No Load Operation)
  • Thermally Enhanced 16-lead MSOP Package

Typical Application

LT3798 Typical Application
LT3798 Typical Application


The LT®3798 is a constant-voltage/constant-current isolated flyback controller that combines active power factor correction (PFC) with no opto-coupler required for output voltage feedback into a single-stage converter. A LT3798 based design can achieve a power factor of greater than 0.97 by actively modulating the input current, allowing compliance with most Harmonic Current Emission requirements.

The LT3798 is well suited for a wide variety of off-line applications. The input range can be scaled up or down, depending mainly on the choice of external components. Efficiencies higher than 86% can be achieved with output power levels up to 100W. In addition, the LT3798 can easily be designed into high DC input applications.


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

Part Number Package Code Temp Package
LT3798EMSE#PBF MS-16E MSE E 05-08-1667 RoHS
LT3798EMSE#TRPBF MS-16E MSE E 05-08-1667 RoHS
LT3798HMSE#PBF MS-16E MSE H 05-08-1667 RoHS
LT3798HMSE#TRPBF MS-16E MSE H 05-08-1667 RoHS
LT3798IMSE#PBF MS-16E MSE I 05-08-1667 RoHS
LT3798IMSE#TRPBF MS-16E MSE I 05-08-1667 RoHS
LT3798MPMSE#PBF MS-16E MSE MP 05-08-1667 RoHS
LT3798MPMSE#TRPBF MS-16E MSE MP 05-08-1667 RoHS

LT3798 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
LT3798EMSE#PBF MS-16E E $3.22 $2.25 Yes
LT3798EMSE#TRPBF MS-16E E $2.31 Yes
LT3798HMSE#PBF MS-16E H $4.11 $2.88 Yes
LT3798HMSE#TRPBF MS-16E H $2.94 Yes
LT3798IMSE#PBF MS-16E I $3.70 $2.59 Yes
LT3798IMSE#TRPBF MS-16E I $2.65 Yes
LT3798MPMSE#PBF MS-16E MP $9.99 $6.99 Yes
LT3798MPMSE#TRPBF MS-16E MP $7.05 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
DC1817B LT3798EMSE Isolated Demo Board VIN = 90VAC to 265VAC, VOUT = 24V @ 2A High Voltage $200.00
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Click here to view our complete list of demo boards


  • Offline 5W to 100W+ Applications
  • High DC VIN Isolated Applications
  • Offline Bus Converter (12V, 24V or 48V Outputs)

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