LT3591

1

3591f

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Cellular Phones

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PDAs, Handheld Computers

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Digital Cameras

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MP3 Players

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GPS Receivers

TYPICAL APPLICATION

FEATURES

APPLICATIONS

DESCRIPTION

White LED Driver with

Integrated Schottky in

3mm × 2mm DFN

specifically designed to drive up to ten white LEDs in series

from a Li-Ion cell. Series connection of the LEDs provides

identical LED currents resulting in uniform brightness

and eliminating the need for ballast resistors. The device

features a unique high side LED current sense that enables

the part to function as a “one wire current source;” one

side of the LED string can be returned to ground anywhere,

allowing a simpler one wire LED connection. Traditional

LED drivers use a grounded resistor to sense LED current,

requiring a 2-wire connection to the LED string.

The high switching frequency allows the use of tiny induc-

tors and capacitors. A single pin performs both shutdown

and accurate LED dimming control. Few external compo-

nents are needed: open-LED protection and the Schottky

diode are all contained inside a low profile 3mm × 2mm

DFN package.

Li-Ion Driver for Ten White LEDs

■

Drives Up to Ten White LEDs from a 3V Supply

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High Side Sense Allows “One Wire Current Source”

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Internal Schottky Diode

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One Pin Dimming and Shutdown

■

■

42V Open LED Protection

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1MHz Switching Frequency

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±5% Reference Accuracy

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■

Requires Only 2.2µF Output Capacitor

■

Low Profile 8-Lead DFN Package

(3mm × 2mm × 0.75mm)

Conversion Efficiency

CTRL

22

µH

3V TO 5V

10

Ω

3591 TA01a

LT3591

SHUTDOWN AND

DIMMING CONTROL

SW

CAP

LED

GND

2.2

µF

1

µF

LED CURRENT (mA)

0

60

20

3591 TA01b

5

10

15

80

70

55

65

75

10 LEDs

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

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

the property of their respective owners.