LT3512

1

3512f

TYPICAL APPLICATION

DESCRIPTION

Monolithic High Voltage

Isolated Flyback Converter

The LT3512 is a high voltage monolithic switching regula-

tor specifically designed for the isolated flyback topology.

No third winding or opto-isolator is required for regula-

tion as the part senses output voltage directly from the

primary-side flyback waveform. The device integrates a

420mA, 150V power switch, high voltage circuitry, and

control into a high voltage 16-lead MSOP package with

four leads removed.

The LT3512 operates from an input voltage range of 4.5V

to 100V and delivers up to 4.5W of isolated output power.

Two external resistors and the transformer turns ratio

easily set the output voltage. Off-the-shelf transformers

are available for several applications. The high level of

integration and the use of boundary mode operation results

in a simple, clean, tightly regulated application solution to

the traditionally tough problem of isolated power delivery.

48V to 5V Isolated Flyback Converter

FEATURES

APPLICATIONS

Opto-Isolator Required for Regulation

Load Regulation

Switch Driver

Supplies

EN/UVLO

SW

VC

GND BIAS

LT3512

3512 TA01a

57.6k

12.7k

36V TO 72V

+

5V

0.5A

–

4:1

1M

43.2k

1μF

11μH

175μH

47μF

4.7nF

4.7μF

10k

169k

LOAD CURRENT (mA)

0

4.75

4.85

4.95

5.05

100

200

400

300

3512 TA01b

5.15

5.25

4.80

4.90

5.00

5.10

5.20

500

Output Load and Line Regulation

L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks

property of their respective owners. Protected by U.S. Patents, including 5438499, 7471522.