Isolated Flyback DC/DC Controller operates up to 150°C.

Press Release Summary:

With input range of 5-100 V, Model LT3748H operates in boundary mode, current-mode control switching scheme, resulting in ±5% typical regulation over full line, load, and temperature range. Device facilitates design of isolated DC/DC converter since there is no requirement for opto-isolator, third winding, or signal transformer for feedback. Housed in MSOP-16 package, IC drives external N-channel power MOSFET, making it suited for automotive, industrial, telecom, and datacom applications.

Original Press Release:

100V Isolated Flyback DC/DC Controller Operates up to 150°C

MILPITAS, CA - - Linear Technology Corporation announces the LT3748H, a high input voltage isolated flyback DC/DC controller with guaranteed operation for junction temperatures as high as 150°C. This device significantly simplifies the design of an isolated DC/DC converter since there is no requirement for an opto-isolator, third winding or signal transformer for feedback, as the output voltage is sensed from the primary-side flyback signal. The LT3748 operates over a 5V to 100V input voltage range and drives an external N-channel power MOSFET, making it well suited for a wide variety of automotive, industrial, telecom and datacom applications.

The LT3748 operates in a boundary mode, current-mode control switching scheme, resulting in +/-5% typical regulation over the full line, load and temperature range. Boundary mode also permits the use of a smaller transformer compared to equivalent continuous conduction mode designs. The output voltage is easily set by two external resistors and the transformer turns ratio. Several off-the-shelf transformers identified in the data sheet can be used for numerous applications. The high level of integration and the use of boundary mode operation results in a simple, clean application solution to the traditional challenge of isolated power delivery. Additional features include an onboard low drop regulator for IC power, programmable soft start, undervoltage lockout, adjustable current limit and output voltage temperature compensation.

The LT3748H is available in a small MSOP-16 package with 4 pins removed for additional high voltage pin spacing. The 1,000 piece price starts at $3.71 each. For more information, visit

Summary of Features: LT3748H

o -40°C to 150°C Guaranteed Junction Temperature Operation

o VIN Range from 5V to 100V

o No Opto-isolator, Transformer or Third Winding Required for Feedback

o Drives External N-Channel Power MOSFET

o Current-Mode Control

o Boundary Mode Operation

o VOUT Set with Two External Resistors

o Off-the-Shelf Transformers

o Programmable Soft-Start

o Programmable Undervoltage Lockout

o Output Voltage Temperature Compensation

About Linear Technology

Linear Technology Corporation, a member of the S&P 500, has been designing, manufacturing and marketing a broad line of high performance analog integrated circuits for major companies worldwide for three decades. The Company's products provide an essential bridge between our analog world and the digital electronics in communications, networking, industrial, automotive, computer, medical, instrumentation, consumer, and military and aerospace systems. Linear Technology produces power management, data conversion, signal conditioning, RF and interface ICs, and µModule® subsystems.

LT, LTC, LTM, µModule and are registered trademarks of Linear Technology Corp. All other trademarks are the property of their respective owners.

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