LT3748 - 100V Isolated Flyback Controller

Features

  • 5V to 100V Input Voltage Range
  • 1.9A Average Gate Drive Source and Sink Current
  • Boundary Mode Operation
  • No Transformer Third Winding or Opto-Isolator Required for Regulation
  • Primary-Side Winding Feedback Load Regulation
  • VOUT Set with Two External Resistors
  • INTVCC Pin for Control of Gate Driver Voltage
  • Programmable Soft Start
  • Programmable Undervoltage Lockout
  • Available in MSOP Package
Designed for Automotive and Transportation Applications
AEC-Q100 data available for specific packages


Typical Application

LT3748 Typical Application
LT3748 Typical Application

Description

The LT3748 is a switching regulator controller specifically designed for the isolated flyback topology and capable of high power. It drives a low side external N-channel power MOSFET from an internally regulated 7V supply. No third winding or opto-isolator is required for regulation as the part senses the isolated output voltage directly from the primary-side flyback waveform.

The LT3748 utilizes boundary mode to provide a small magnetic solution without compromising load regulation. Operating frequency is set by load current and transformer magnetizing inductance. The gate drive of the LT3748 combined with a suitable external MOSFET allow it to deliver load power up to several tens of watts from input voltages as high as 100V.

The LT3748 is available in a high voltage 16-lead MSOP package with four leads removed.

Packaging

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

Part Number Package Code Temp Package
Drawing
RoHS
LT3748EMS#PBF MS-16 MS E 05-08-1847 Yes
LT3748EMS#TRPBF MS-16 MS E 05-08-1847 Yes
LT3748HMS#PBF MS-16 MS H 05-08-1847 Yes
LT3748HMS#TRPBF MS-16 MS H 05-08-1847 Yes
LT3748IMS#PBF MS-16 MS I 05-08-1847 Yes
LT3748IMS#TRPBF MS-16 MS I 05-08-1847 Yes
LT3748MPMS#PBF MS-16 MS MP 05-08-1847 Yes
LT3748MPMS#TRPBF MS-16 MS MP 05-08-1847 Yes


LT3748 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
(1-99)
Price
(1k)*
RoHS
LT3748EMS#PBF MS-16 E $4.46 $3.12 Yes
LT3748EMS#TRPBF MS-16 E $3.18 Yes
LT3748HMS#PBF MS-16 H $5.66 $3.71 Yes
LT3748HMS#TRPBF MS-16 H $3.77 Yes
LT3748IMS#PBF MS-16 I $4.93 $3.45 Yes
LT3748IMS#TRPBF MS-16 I $3.51 Yes
LT3748MPMS#PBF MS-16 MP $13.22 $9.25 Yes
LT3748MPMS#TRPBF MS-16 MP $9.31 Yes
Buy NowRequest Samples
* 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
DC1557A LT3748EMS Isolated Demo Board | 30V Vin 75V; Vout = 12V @ 1A $175.00
DC1694B LT3748EMS Isolated Demo Board | 22V ≤ VIN ≤ 75V; VOUT = 12V @ 2.5A $175.00
DC1860B LT3748EMS Isolated Demo Board | 10V ≤ Vin ≤ 15V; Vout = 52.5V @ 0.7A $175.00
DC1961A LT8309ES5/LT3748EMS Isolated Demo Board | 36V ≤ VIN ≤ 72V; VOUT = 12V @ 5A $175.00
Buy Now
Click here to view our complete list of demo boards

Designed for Automotive and Transportation Applications

AEC-Q100 data is available for these specific part numbers. Please contact your local sales representative for more information regarding reliability reports or to inquire about parts that are not included. For more information, view our Automotive and Transportation page

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LT3748HMS#PBF MS-16 H $5.66 $3.71 Yes
LT3748HMS#TRPBF MS-16 H $3.77 Yes
LT3748IMS#PBF MS-16 I $4.93 $3.45 Yes
LT3748IMS#TRPBF MS-16 I $3.51 Yes
LT3748MPMS#PBF MS-16 MP $13.22 $9.25 Yes
LT3748MPMS#TRPBF MS-16 MP $9.31 Yes
Buy NowRequest Samples
* 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.

Applications

  • Isolated Telecom Converters
  • High Power Automotive Supplies
  • Isolated Industrial Power Supplies

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Design Tools

LTspice

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

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Models for the following parts are available in LTspice IV:
LT3748

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