LT3844

1

3844fb

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

High Voltage, Current Mode

Switching Regulator Controller with

Programmable Operating Frequency

High Voltage Step-Down Regulator 48V to 12V, 50W

Efficiency and Power Loss

vs Load Current

500kHz

The LT

low part count, high efficiency supplies. It offers a wide

4V to 60V input range (7.5V minimum start-up voltage)

and can implement step-down, step-up, inverting and

SEPIC topologies.

The LT3844 includes Burst Mode operation, which reduces

quiescent current below 120μA and maintains high effi-

ciency at light loads. An internal high voltage bias regulator

allows for simple biasing.

Additional features include current mode control for fast

line and load transient response; programmable fixed

operating frequency that can be synchronized to an ex-

ternal clock for noise sensitive applications; a gate driver

capable of driving large N-channel MOSFETs; a precision

undervoltage lockout function; 10μA shutdown current;

short-circuit protection and a programmable soft-start

function.

The LT3844 is available in a 16-lead thermally enhanced

TSSOP package.

L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.

Burst Mode is a registered trademark of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

Protected by U.S. Patents, including 5731694, 6498466, 6611131

SHDN

BURST_EN

SYNC

BOOST

TG

SW

PGND

SGND

LT3844

3844 TA01

R7

49.9k

12V

50W

68μF

680p

22μF

120pF

68μF

10k

10Ω

1000pF

0.22μF

10μH

33μF

0.015Ω

14.7k

130k

82.5k

1M

1μF

PDS5100H

Si7850DP

36V TO 60V

LOAD CURRENT (A)

76

82

80

78

90

88

86

84

0

3

2

1

7

6

5

4

3844 TA01b

0.1

10

1

LOSS

EFFICIENCY