LT3492
1
3492fa
FEATURES
APPLICATIONS
DESCRIPTION
Triple Output LED Driver
with 3000:1 PWM Dimming
The LT
®
3492 is a triple output DC/DC converter designed
to operate as a constant-current source and is ideal for
driving LEDs. The LT3492 works in buck, boost or buck-
boost mode. The LT3492 uses a fi xed frequency, current
mode architecture resulting in stable operation over a
wide range of supply and output voltages. A frequency
adjust pin allows the user to program switching frequency
between 330kHz and 2.1MHz to optimize effi ciency and
external component size.
The external PWM input provides 3000:1 LED dimming
on each channel. Each of the three channels has a built-in
gate driver to drive an external LED-disconnect P-channel
MOSFET, allowing high dimming range. The output current
range of each channel of the LT3492 is programmed with
an external sense resistor.
The CTRL pin is used to adjust the LED current either for
analog dimming or overtemperature protection.
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True Color PWM™ Dimming Delivers Up to 3000:1
Dimming Ratio
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Built-In Gate Driver for PMOS LED Disconnect
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Three Independent Driver Channels with 600mA,
60V Internal Switches
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Operates in Buck, Boost, Buck-Boost Modes
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CTRL Pin Accurately Sets LED Current Sense
Threshold Over a Range of 10mV to 100mV
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Adjustable Frequency: 330kHz to 2.1MHz
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Open LED Protection
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Wide Input Voltage Range:
Operation from 3V to 30V
Transient Protection to 40V
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Surface Mount Components
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28-Lead (4mm × 5mm) QFN and TSSOP Packages
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RGB Lighting
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Billboards and Large Displays
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Automotive and Avionic Lighting
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Constant-Current Sources
High Dimming Ratio Triple Output Buck-Mode LED Power Supply
3000:1 PWM Dimming at 100Hz
TYPICAL APPLICATION
0.3A
0.47µF
0.47µF
ISN1
330m 330m
TG1
PV
IN
58V
10 LEDs
33µH
ISP1
0.3A
ISN2
TG2
33µH
ISP2
0.3A
0.47µF
ISN3
1µF
s3
330m
10k
150k
49.9k
680pF
3492 TA01a
TG3
33µH
ISP3
SW1 SW2
LT3492
GND
SW3 TG1-3
V
C1-3
V
REF
CTRL1-3
ISP1-3
ISN1-3
V
IN
PWM1-3
SHDN
V
IN
3V TO 24V
1µF
FADJ
OVP1-3
1.3MHz
L, LT, LTC, LTM, Linear Technology and the Linear logo 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. Protected by U.S. Patents,
including 7199560, 7321203, and others pending.
PWM
5V/DIV
1µs/DIV
3492 TA01b
I
LED
0.2A/DIV
I
L
0.5A/DIV