LT3466-1_15 Datasheet, PDF (1/20 Pages) Linear Technology – White LED Driver and Boost Converter in 3mm 3mm DFN Package

FEATURES
■ _{Drives Up to 10 White LEDs from a 3.6V Supply}
■ _{Two Independent Step-Up DC/DC Converters}
■ _{Independent Dimming and Shutdown Control}
of the Outputs
■ _{±1.5% Output Voltage Accuracy (Boost Converter)}
■ _{±4% LED Current Programming Accuracy}
■ _{Internal Schottky Diodes}
■ _{Internal Soft-Start Eliminates Inrush Current}
■ _{Output Overvoltage Protection (39.5V Max VOUT)}
■ _{Fixed Frequency Operation Up to 2MHz}
■ _{83% Efficiency Driving 8 White LEDs at 15mA}
from a 3.6V Supply
■ _{Wide Input Voltage Range: 2.7V to 24V}
■ _{Tiny (3mm × 3mm) 10-Lead DFN Package}
U
APPLICATIO S
■ _{White LED and OLED Displays}
■ _{Digital Cameras, Sub-Notebook PCs}
■ _{PDAs, Handheld Computers}
■ _{TFT - LCD Bias Supply}
■ _Automotive
LT3466-1
White LED Driver and Boost
Converter in 3mm × 3mm
DFN Package
DESCRIPTIO
LT^®3466-1 is a dual switching regulator that combines a
white LED driver and a boost converter in a low profile,
small footprint (3mm × 3mm × 0.75mm) DFN package.
The LED driver can be configured to drive up to 10 White
LEDs in series and the boost converter can be used for
generating the LCD bias voltages or driving a secondary
OLED display. 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 LT3466-1 provides independent dimming and shut-
down control of the two converters. The operating fre-
quency can be set with an external resistor over a 200kHz
to 2MHz range. The white LED driver features a low 200mV
reference, thereby minimizing power loss in the current
setting resistor for better efficiency. The boost converter
achieves ±1.5% output voltage accuracy by the use of a
precision 0.8V reference. Protection features include out-
put overvoltage protection and internal soft-start. Wide
input supply range allows operation from 2.7V to 24V.
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
TYPICAL APPLICATIO
3V TO 5V
33µH
1µF
33µH
SW1
V_IN
SW2
6 LEDs
V_OUT1
LT3466-1
V_OUT2
1µF
16V
1µF
30mA
475k
FB1
FB2
CTRL1
R_T GND CTRL2
10Ω
SHUTDOWN ^63.4k
AND DIMMING
CONTROL 1
SHUTDOWN
AND DIMMING
CONTROL 2
24.9k
34661 F01a
Figure 1. Li-Ion Powered Driver for 6 White LEDs and OLED Display
Conversion Efficiency
90
V_IN = 3.6V
85
LED DRIVER
80
BOOST CONVERTER
75
70
65
60
55
50
0
5 10 15 20 25 30
OUTPUT CURRENT (mA)
34661 F01b
34661f
1