LT3465_15 Datasheet, PDF (1/16 Pages) Linear Technology – 1.2MHz/2.4MHz White LED Drivers with Built-in Schottky in ThinSOT

LT3465/LT3465A
1.2MHz/2.4MHz White
LED Drivers with Built-in
Schottky in ThinSOT
FEATURES
■ _{Inherently Matched LED Current}
■ _{Drives Up to Six LEDs from a 3.6V Supply}
■ _{No External Schottky Diode Required}
■ _{1.2MHz Switching Frequency (LT3465)}
■ _{2.4MHz Switching Frequency Above AM Broadcast}
Band (LT3465A)
■ _{VIN Range: 2.7V to 16V}
■ _{VOUT(MAX) = 30V}
■ _{Automatic Soft-Start (LT3465)}
■ _{Open LED Protection}
■ _{High Efficiency: 81% (LT3465) 79% (LT3465A)}
Typical
■ _{Requires Only 0.22µF Output Capacitor}
■ _{Low Profile (1mm) SOT-23}
U
APPLICATIO S
■ _{Cellular Phones}
■ _{PDAs, Handheld Computers}
■ _{Digital Cameras}
■ _{MP3 Players}
■ _{GPS Receivers}
DESCRIPTIO
The LT^®3465/LT3465A are step-up DC/DC converters
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.
These devices integrate the Schottky diode required exter-
nally on competing devices. Additional features include
output voltage limiting when LEDs are disconnected, one-
pin shutdown and dimming control. The LT3465 has
internal soft-start.
The LT3465 switches at 1.2MHz, allowing the use of tiny
external components. The faster LT3465A switches at
2.4MHz. Constant frequency switching results in low input
noise and a small output capacitor. Just 0.22µF is required
for 3-, 4- or 5-LED applications.
The LT3465 and LT3465A are available in the low profile
(1mm) 6-lead SOT-23 (ThinSOT^TM) package.
, LTC and LT are registered trademarks of Linear Technology Corporation. ThinSOT is a
trademark of Linear Technology Corporation. All other trademarks are the property of their
respective owners.
TYPICAL APPLICATIO
3V TO 5V
L1
22µH
SW V_OUT
V_IN
C1
LT3465/
SHUTDOWN
1µF
LT3465A
C2
0.22µF
AND DIMMING
CTRL
FB
CONTROL
GND
10Ω
C1, C2: X5R OR X7R DIELECTRIC
L1: MURATA LQH32CN220
3465A F01a
Figure 1. Li-Ion Powered Driver for Four White LEDs
Conversion Efficiency
82 _{VIN = 3.6V}
80 4 LEDs
78
76
74
72
70
68
66
64
62
LT3465
LT3465A
60
0
5
10
15
20
LED CURRENT (mA)
3465A F01b
3465afa
1