LT3959

1

3959f

TYPICAL APPLICATION

FEATURES

DESCRIPTION

Wide Input Voltage Range

Boost/SEPIC/Inverting Converter

with 6A, 40V Switch

2.5V to 24V Input, 12V Output SEPIC Converter

Excellent for Automotive 12V Post Regulator

APPLICATIONS

with a Single Feedback Pin

n

PGOOD Output Voltage Status Report

with One External Resistor

Hysteresis

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

ThinSOT are trademarks of Linear Technology Corporation. All other trademarks are the

property of their respective owners. Protected by U.S. Patents, including 7825665.

controller which is capable of regulating either positive or

negative output voltages from a single feedback pin. It can

be configured as a boost, SEPIC or inverting converter.

It features an internal low side N-channel MOSFET rated

for 6A at 40V and driven from an internal regulated sup-

current-mode architecture results in stable operation over

a wide range of supply and output voltages. The operating

frequency of LT3959 can be set over a 100kHz to 1MHz

range with an external resistor, or can be synchronized to

an external clock using the SYNC pin.

The LT3959 features soft-start and frequency foldback

functions to limit inductor current during start-up and

output short-circuit. A window comparator on the FBX

pin reports via the PGOOD pin, providing output voltage

status indication.

Efficiency vs Output Current

OUTPUT CURRENT (mA)

0

90

95

100

600

1000

3959 TA01b

85

200

400

800

80

75

70

65

60

LT3959

2.5V TO

24V

22μF

50V

×2

27.4k

300kHz

4.7μF

50V

GND

DRIVE

FBX

SGND

EN_UVLO

PGOOD

SYNC

TIE TO SGND

IF NOT USED

RT

SS

L1A

L1B

GNDK

SW

124k

121k

0.1μF

7.5k

22nF

105K

150k

4.7μF

12V

3959 TA01a

15.8K

47μF

16V

×2