LT3591EDDB Datasheet, PDF (1/16 Pages) Linear Integrated Systems – White LED Driver with Integrated Schottky in 3mm 2mm DFN

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 PWM}^TM _{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 Profile 8-Lead DFN Package}
(3mm × 2mm × 0.75mm)
APPLICATIONS
■ _{Cellular Phones}
■ _{PDAs, Handheld Computers}
■ _{Digital Cameras}
■ _{MP3 Players}
■ _{GPS Receivers}
LT3591
White LED Driver with
Integrated Schottky in
3mm × 2mm DFN
DESCRIPTION
The LT^®3591 is a fixed frequency step-up DC/DC converter
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.
, 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.
TYPICAL APPLICATION
V_IN
3V TO 5V
Li-Ion Driver for Ten White LEDs
SHUTDOWN AND
DIMMING CONTROL
22µH
1µF
CTRL
V_IN
CAP
LT3591
SW
LED
GND
R_SENSE
10Ω
2.2µF
3591 TA01a
Conversion Efficiency
80
V_IN = 3.6V
10 LEDs
75
70
65
60
55
0
5
10
15
20
LED CURRENT (mA)
3591 TA01b
3591f
1