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LT3465

White LED Step-Up Converter with Built-In Schottky in ThinSOT

Linear Technology 

FEATURES

s Inherently Matched LED Current

s Drives Up to Six LEDs from a 3.6V Supply

s No External Schottky Diode Required

s Automatic Soft-Start

s Open LED Protection

s High Efficiency: 81% Typical

s Requires Only 0.22µF Output Capacitor

s Low Profile (1mm) SOT-23 Packaging

U

APPLICATIO S

s Cellular Phones

s PDAs, Handheld Computers

s Digital Cameras

s MP3 Players

s GPS Receivers

Final Electrical Specifications

LT3465

White LED Step-Up

Converter with Built-In

Schottky in ThinSOT

May 2003

DESCRIPTIO

The LT®3465 is a step-up DC/DC converter designed to

drive up to six LEDs in series from a Li-Ion cell. Series

connection of the LEDs provides identical LED currents

and eliminates the need for ballast resistors. This device

integrates the Schottky diode required externally on com-

peting devices. Additional features include output voltage

limiting when LEDs are disconnected, one-pin shutdown

and dimming control, and internal soft-start.

The LT3465 switches at 1.2MHz, allowing the use of tiny

external components. Constant frequency switching re-

sults in low input noise and a small output capacitor. Just

0.22µF is required for 3-, 4-, 5- or 6-LED applications.

The LT3465 is available in a low profile (1mm) 6-lead

SOT-23 (ThinSOTTM) package.

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

ThinSOT is a trademark of Linear Technology Corporation.

TYPICAL APPLICATIO

3V TO 5V

L1

22µH

SW VOUT

VIN

C1

SHUTDOWN

1µF

LT3465

C2

0.22µF

AND DIMMING

CTRL

FB

CONTROL

GND

10Ω

C1, C2: X5R OR X7R DIELECTRIC

L1: MURATA LQH32CN220

3465 F01a

Figure 1. Li-Ion Powered Driver for Four White LEDs

Conversion Efficiency

82

80

78

76

74

72

70

0

5

10

15

LED CURRENT (mA)

20

3465 F01b

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.

However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-

tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.

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