LT3518
1
3518ff
For more information www.linear.com/LT3518
Features
applications
Description
Full-Featured LED Driver
with 2.3A Switch Current
The LT
®
3518 is a current mode DC/DC converter with an
internal 2.3A, 45V switch specifically designed to drive
LEDs. The LT3518 operates as a LED driver in boost, buck
mode and buck-boost mode. It combines a traditional
voltage loop and a unique current loop to operate as a
constant-current source or constant-voltage source. Pro
-
grammable switching frequency allows optimization of the
external components for efficiency or component size. The
switching frequency of the LT3518 can be synchronized
to an external clock signal. The LED current is externally
programmable with a 100mV sense resistor. The external
PWM input provides 3000:1 LED dimming. The CTRL pin
provides further 10:1 dimming ratio.
The LT3518 is available in the tiny footprint 16-lead QFN
(4mm × 4mm) and the 16-pin TSSOP package. The LT3518
provides a complete solution for both constant-voltage
and constant-current applications.
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3000:1 True Color PWM™ Dimming Ratio
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2.3A, 45V Internal Switch
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100mV High Side Current Sense
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Open LED Protection
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Adjustable Frequency: 250kHz to 2.5MHz
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Wide Input Voltage Range:
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Operation from 3V to 30V
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Transient Protection to 40V
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Operates in Boost, Buck Mode and Buck-Boost Mode
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Gate Driver for PMOS LED Disconnect
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Constant-Current and Constant-Voltage Regulation
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CTRL Pin Provides 10:1 Analog Dimming
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Low Shutdown Current: <1µA
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Available in (4mm × 4mm) 16-Lead QFN and 16-Pin
TSSOP Packages
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Display Backlighting
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Automotive and Avionic Lighting
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Illumination
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Scanners
1.5A Buck Mode LED Driver
Efficiency
L, LT, LTC and LTM are registered trademarks and True Color PWM is a trademark of Analog
Devices Inc. All other trademarks are the property of their respective owners. Protected by U.S.
Patents, including 7199560, 7321203, 7746300. Patent Pending.
1.5A
10µF
15µH
2.2µF
0.1µF
68mΩ M1
2.2µF
V
REF
ISP
TGEN GNDV
REF
VC
16.9k
1MHz
3518 TA01a
0.1µF
V
IN
SHDN
CTRL
PWM
SYNC
FB
SS
RT
SW
PV
IN
24V
V
IN
3.3V
ISN
LT3518
TG
PWM
PWM DUTY CYCLE (%)
0
40
EFFICIENCY (%)
50
60
70
80
90
100
20 40 60 80
3518 TA01b
100
CTRL = V
REF
typical application