FEATURES
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LT3592
500mA Wide Input Voltage
Range Step-Down LED Driver
with 10:1 Dimming
DESCRIPTION
The LT
®
3592 is a fixed frequency step-down DC/DC con-
verter designed to operate as a constant-current source.
An external sense resistor monitors the output current
allowing accurate current regulation, ideal for driving
high current LEDs. The output current can be dimmed
by a factor of 10 using an external signal for nighttime
brake lights.
The high switching frequency offers several advantages by
permitting the use of a small inductor and small ceramic
capacitors. Small components combined with the LT3592’s
10-pin DFN leadless surface mount package save space and
cost versus alternative solutions. The constant switching
frequency combined with low-impedance ceramic capaci-
tors result in low, predictable output ripple.
A wide input voltage range of 3.6V to 36V makes the
LT3592 useful in a variety of applications. Current mode
PWM architecture provides fast transient response and
cycle-by-cycle current limiting. Thermal shutdown provides
additional protection.
L,
LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
All other trademarks are the property of their respective owners.
Wide Input Voltage Range
Operation from 3.6V to 36V
Resistor Adjustable 400kHz–2.2MHz Switching
Frequency
Shorted and Open LED Protected
Internal Switch Current Sense Resistor
External Resistor Programs LED Current, Pin
Selects 10:1 Ratio
50mA/500mA LED Current Settings
Catch Diode Current Sense to Prevent Runaway at
High V
IN
Small Thermally Enhanced 10-Lead DFN
(2mm
×
3mm) and MSOP-10 Packages
APPLICATIONS
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Automotive Signal Lighting
Industrial Lighting
Constant-Current, Constant Voltage Supplies
TYPICAL APPLICATION
50/500mA Two Series Red LED Driver
V
IN
7V TO 32V
V
IN
1μF
BOOST
LT3592
SW
EFFICIENCY (%)
DA
CAP
OUT
V
FB
10k
0.1μF 10μH
Efficiency for 2 Red LEDs, L = 10μH, 900kHz
100
95
90
85
80
75
70
65
BRIGHT 500mA
ON
BRAKE
SHDN
BRIGHT
R
T
+
200/20mV
–
51k
0.4Ω
4.7μF
60
55
50
3592 TA01a
140k
900kHz
GND
4
8
16
12
20
INPUT VOLTAGE (V)
24
28
3592 TA01b
3592fc
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LINEAR [ LINEAR INTEGRATED SYSTEMS ]
