LT3496



3496ff

Features

applications

Description

Triple Output LED Driver

to operate as a constant-current source and is ideal for

driving LEDs. The LT3496 works in buck, boost or buck-

boost mode. The LT3496 uses a fixed frequency, current

mode architecture resulting in stable operation over a

wide range of supply and output voltages. A frequency

adjust pin allows the user to program switching frequency

between 330kHz and 2.1MHz to optimize efficiency and

external component size.

The LT3496 supports 3000:1 dimming control on each

channel. Each of the three regulators is independently

operated by that channel’s PWM signal. The PWM feature

allows precise adjustment of the color mixing or dimming

ratio of the LED source. Each of the three channels has

a built-in gate driver to drive an external LED-disconnect

P-channel MOSFET, allowing high dimming range. The

output current range of each channel of the LT3496 is

programmed with an external sense resistor.

The CTRL pins are used to adjust the LED currents either

for analog dimming or overtemperature protection.

L

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

ThinSOT and True Color PWM are trademarks of Linear Technology Corporation. All other

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

7199560, 7321203, and others pending.

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True Color PWM™ Dimming Delivers Up to 3000:1

Dimming Ratio

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Built-In Gate Driver for PMOS LED Disconnect

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Three Independent Driver Channels with 750mA,

45V Internal Switches

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Operates in Buck, Boost, Buck-Boost Modes

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CTRL Pin Accurately Sets LED Current Sense

Threshold Over a Range of 10mV to 100mV

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Adjustable Frequency: 330kHz to 2.1MHz

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Open LED Protection

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Operation from 3V to 30V

Transient Protection to 40V

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Surface Mount Components

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28-Lead (4mm

× 5mm) QFN and TSSOP Packages

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RGB Lighting

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Billboards and Large Displays

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Automotive and Avionic Lighting

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Constant-Current Sources

High Dimming Ratio Triple Output LED Power Supply

3000:1 PWM Dimming at 120Hz

typical application

PWM

5V/DIV

0.5µs/DIV

3496 TA01b

0.5A/DIV

0.5A/DIV

0.5A

0.47µF 0.47µF

LED1

200m

200m

TG1

42V

7 LEDs

18µH

CAP1

0.5A

LED2

TG2

18µH

CAP2

0.5A

0.47µF

LED3

1µF

3

200m

470pF

3496 TA01a

TG3

18µH

CAP3

SW1

SW2

LT3496

GND

SW3 TG1, TG2, TG3

VC1, VC2, VC3

CTRL1, CTRL2, CTRL3

OVP1, OVP2, OVP3

CAP1, CAP2, CAP3

LED1, LED2, LED3

PWM1, PWM2, PWM3

SHDN

PWM1, PWM2, PWM3

SHDN

3V TO 24V

1µF

22k