LT3748



3748f

Features

applications

Description

100V Isolated

Flyback Controller

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.

Operatingfrequencyissetbyloadcurrentandtransformer

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.

25W, 12V Output, Isolated Telecom Supply

n

5V to 100V Input Voltage Range

n

1.9A Average Gate Drive Source and Sink Current

n

Boundary Mode Operation

n

No Transformer Third Winding or Opto-Isolator

Required for Regulation

n

Primary-Side Winding Feedback Load Regulation

n

n

n

Programmable Soft Start

n

Programmable Undervoltage Lockout

n

Available in MSOP Package

n

Isolated Telecom Converters

n

High Power Automotive Supplies

n

Isolated Industrial Power Supplies

Output Load and Line Regulation

typical application

L

, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. All other trademarks are the property of their respective owners.

Protected by U.S. Patents, including 5438499 and 7471522.

EN/UVLO

TC

SS

GND

LT3748

3748 TA01a

56.2k

2nF

36V TO 72V

12V

2A

4:1

412k

15.4k

GATE

SENSE

4700pF

6.04k

243k

0.033

10k

LOAD CURRENT (A)

0

11.4

11.6

11.8

12.0

12.2

14.4

12.6

0.5

1.0

1.5

2.0

3748 TA01b