LT3517

1

3517ff

FEATURES

APPLICATIONS

DESCRIPTION

Full-Featured LED Driver

with 1.5A Switch Current

The LT

internal 1.5A, 45V switch specifically designed to drive

LEDs. The LT3517 operates as a LED driver in boost,

buck mode and buck-boost mode. It combines a tradi-

tional voltage loop and a unique current loop to operate

as a constant-current source or constant-voltage source.

Programmable switching frequency allows optimization of

the external components for efficiency or component size.

The switching frequency of LT3517 can be synchronized

to an external clock signal. The LED current is externally

programmable with a 100mV sense resistor. The external

PWM input provides up to 5000:1 LED dimming. The CTRL

pin provides further 10:1 dimming ratio.

The LT3517 is available in the tiny footprint 16-lead QFN

(4mm × 4mm) and the 16-pin TSSOP packages. The

LT3517 provides a complete solution for both constant-

voltage and constant-current applications.

■

5000:1 True Color PWM

■

1.5A, 45V Internal Switch

■

100mV High Side Current Sense

■

Open LED Protection

■

Adjustable Frequency: 250kHz to 2.5MHz

■

Wide Input Voltage Range:

Operation from 3V to 30V

Transient Protection to 40V

■

Operates in Boost, Buck Mode and Buck-Boost Mode

■

Gate Driver for PMOS LED Disconnect

■

Constant-Current and Constant-Voltage Regulation

■

CTRL Pin Provides 10:1 Analog Dimming

■

Low Shutdown Current: <1μA

■

Available in (4mm × 4mm) 16-Lead QFN and 16-Pin

TSSOP Packages

■

Display Backlighting

■

Automotive and Avionic Lighting

■

Illumination

■

Scanners

1A

10μF

15μH

2.2μF

0.1μF

100mΩ

2.2μF

ISP

TGEN

GND

16.9k

1MHz

3517 TA01a

0.1μF

SHDN

CTRL

PWM

SYNC

FB

SS

RT

SW

24V

3.3V

ISN

LT3517

TG

PWM

1A Buck Mode LED Driver

Efficiency

PWM DUTY CYCLE (%)

0

40

50

60

70

80

90

100

20

40

60

80

3517 TA01b

100

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

trademarks and True Color PWM is a trademark of Linear Technology Corporation. All other

trademarks are the property of their respective owners. Protected by U.S. Patents, including

7199560, 7321203, 7746300.

TYPICAL APPLICATION