1

LT3466

3466fa

Dual Full Function White LED

Step-Up Converter with

Built-In Schottky Diodes

Figure 1. Li-Ion Powered Driver for 8/8 White LEDs

per Converter) from a 3.6V Supply

■

Two Independent Step-Up Converters Capable of

Driving Asymmetric LED Strings

of the Two LED Strings

■

(Eight per Driver) from a 3.6V Supply

Enhanced TSSOP Packages

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

■

Main/Sub Displays

■

Automotive

LT

specifically designed to drive up to 20 White LEDs (10 in

series per converter) with a constant current. Series

connection of the LEDs provides identical LED currents

resulting in uniform brightness and eliminating the need

for ballast resistors and expensive factory calibration.

The two independent converters are capable of driving

asymmetric LED strings. The dimming of the two LED

strings can also be controlled independently. The LT3466

is ideal for providing backlight for main and sub-displays

in cell phones and other handheld devices.

The LT3466 operating frequency can be set with an

external resistor over a 200kHz to 2MHz range. A low

200mV feedback voltage minimizes power loss in the

current setting resistor for better efficiency. Additional

features include output voltage limiting when LEDs are

disconnected and internal soft-start.

The LT3466 is available in the 10-pin (3mm

× 3mm ×

0.75mm) DFN and 16-pin thermally enhanced TSSOP

packages.

CTRL1

GND CTRL2

SW1

SW2

3V TO 5V

L2

47

µH

1

µF

2.2

µF

2.2

µF

LED1

LED2

L1

47

µH

LT3466

SHUTDOWN

AND DIMMING

CONTROL 2

SHUTDOWN

AND DIMMING

CONTROL 1

FB1

10

Ω

10

Ω

3466 F01a

FB2

63.4k

OFF ON

OFF ON

Conversion Efficiency

LED CURRENT (mA)

0

70

75

20

3466 F01b

60

50

65

55

5

10

15

85

8/8 LEDs

80

DESCRIPTIO

FEATURES

APPLICATIO S

TYPICAL APPLICATIO