DESCRIPTION

The LT®3591 is a fixed frequency step-up DC/DC converter specifi cally 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.

FEATURES

■ Drives Up to Ten White LEDs from a 3V Supply

■ High Side Sense Allows “One Wire Current Source”

■ Internal Schottky Diode

■ One Pin Dimming and Shutdown

■ 80:1 True Color PWMTM Dimming Range

■ 42V Open LED Protection

■ 1MHz Switching Frequency

■ ±5 Reference Accuracy

■ VIN Range: 2.5V to 12V

■ Requires Only 2.2µF Output Capacitor

■ Low Profi le 8-Lead DFN Package (3mm × 2mm × 0.75mm)

APPLICATIONS

■ Cellular Phones

■ PDAs, Handheld Computers

■ Digital Cameras

■ MP3 Players

■ GPS Receivers