LT3519 Datasheet, PDF (1/16 Pages) Linear Technology – LED Driver with Integrated Schottky Diode

FEATURES
n _{Up to 3000:1 True Color PWM™ Dimming}
n _{Wide Input Voltage Range}
Operation from 3V to 30V
Transient Protection to 40V
n _{Floating LED Current Sense from 0V to 45V}
n _{45V, 750mA Internal Switch}
n _{Internal Schottky Diode}
n _{Constant-Current and Constant-Voltage Regulation}
n _{Boost, SEPIC, Buck-Boost Mode or Buck Mode}
Topology
n _{Open LED Protection and Open LED Status Pin}
n _{Programmable Undervoltage Lockout with Hysteresis}
n _{Fixed Frequency: 400kHz (LT3519)}
n _{Internal Compensation}
n _{CTRL Pin Provides Analog Dimming}
n _{Low Shutdown Current: <1μA}
n _{16-Lead MSOP Package}
APPLICATIONS
n _Automotive
n _Industrial
n _{Constant Current Source}
n _{Current Limited Constant Voltage Source}
LT3519
LED Driver with Integrated
Schottky Diode
DESCRIPTION
The LT^®3519 are fixed frequency step-up DC/DC convert-
ers designed to drive LEDs. They feature an internal 45V,
750mA low side switch and Schottky diode. Combining a
traditional voltage feedback and a unique floating current
sense feedback allows these converters to operate as a
constant-voltage source or constant-current source. Inter-
nal compensation simplifies applications. These devices
feature floating LED current sense pins that provide the
most flexibility in choosing a converter configuration to
drive the LEDs. The LED current is externally program-
mable with a 250mV sense resistor. The external PWM
provides up to 3000:1 PWM dimming and the CTRL input
provides analog dimming.
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.
TYPICAL APPLICATION
4W Boost Automotive LED Driver
V_IN
6V TO 30V
68μH
1μF
1M
100k
1M 243k
137k
SW ANODE CATHODE
V_IN
ISP
SHDN/UVLO
ISN
LT3519
V_REF
FB
CTRL
OPENLED
GND
PWM
PWM
V_OUT
4.7μF
2.5Ω
1M
29.4k
38V LED
100mA
M1
3519 TA01a
LED Current vs V_IN
120
V_IN = 6V AND ABOVE
100
80
60
40
20
0
0
10
20
30
V_IN (V)
3519 TA01b
3519f
1