LT3466-1
White LED Driver and Boost
Converter in 3mm × 3mm
DFN Package
U
FEATURES
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.
■
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
)
■
■
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
to2MHzrange.ThewhiteLEDdriverfeaturesalow200mV
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.
■
■
Wide Input Voltage Range: 2.7V to 24V
Tiny (3mm × 3mm) 10-Lead DFN Package
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APPLICATIO S
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White LED and OLED Displays
■
Digital Cameras, Sub-Notebook PCs
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PDAs, Handheld Computers
■
TFT - LCD Bias Supply
, LTC and LT are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
■
Automotive
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TYPICAL APPLICATIO
3V TO 5V
Conversion Efficiency
1µF
90
33µH
33µH
V
IN
= 3.6V
85
80
75
70
65
60
55
50
LED DRIVER
SW1
V
SW2
IN
BOOST CONVERTER
16V
6 LEDs
V
V
OUT2
LT3466-1
OUT1
30mA
1µF
1µF
475k
FB1
FB2
R
CTRL1
GND
CTRL2
T
63.4k
SHUTDOWN
AND DIMMING
CONTROL 1
SHUTDOWN
AND DIMMING
CONTROL 2
10Ω
24.9k
0
5
10
15
20
25
30
OUTPUT CURRENT (mA)
34661 F01a
34661 F01b
Figure 1. Li-Ion Powered Driver for 6 White LEDs and OLED Display
34661f
1