LT3517_12 Datasheet, PDF (1/20 Pages) Linear Technology – Full-Featured LED Driver with 1.5A Switch Current

LT3517
Full-Featured LED Driver
with 1.5A Switch Current
FEATURES
DESCRIPTION
■ _{5000:1 True Color PWM}^™ _{Dimming Ratio}
■ _{1.5A, 45V Internal Switch}
■ _{100mV High Side Current Sense}
■ _{Open LED Protection}
■ _{Adjustable Frequency: 250kHz to 2.5MHz}
■ _{Wide Input Voltage Range:}
Operation from 3V to 30V
Transient Protection to 40V
■ _{Operates in Boost, Buck Mode and Buck-Boost Mode}
■ _{Gate Driver for PMOS LED Disconnect}
■ _{Constant-Current and Constant-Voltage Regulation}
■ _{CTRL Pin Provides 10:1 Analog Dimming}
■ _{Low Shutdown Current: <1μA}
■ _{Available in (4mm × 4mm) 16-Lead QFN and 16-Pin}
TSSOP Packages
APPLICATIONS
■ _{Display Backlighting}
■ _{Automotive and Avionic Lighting}
■ _Illumination
■ _Scanners
The LT^®3517 is a current mode DC/DC converter with an
internal 1.5A, 45V switch specifically designed to drive
LEDs. The LT3517 operates as a LED driver in boost,
buck mode and buck-boost mode. It combines a tradi-
tional voltage loop and a unique current loop to operate
as a constant-current source or constant-voltage source.
Programmable switching frequency allows optimization of
the external components for efficiency or component size.
The switching frequency of LT3517 can be synchronized
to an external clock signal. The LED current is externally
programmable with a 100mV sense resistor. The external
PWM input provides up to 5000:1 LED dimming. The CTRL
pin provides further 10:1 dimming ratio.
The LT3517 is available in the tiny footprint 16-lead QFN
(4mm × 4mm) and the 16-pin TSSOP packages. The
LT3517 provides a complete solution for both constant-
voltage and constant-current applications.
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered
trademarks and 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, 7746300.
TYPICAL APPLICATION
1A Buck Mode LED Driver
PV_IN
24V
V_IN
3.3V
2.2μF
V_REF
PWM
2.2μF
100mΩ
ISP
V_IN
SHDN
ISN TG
SW
LT3517
CTRL
FB
PWM
SS
SYNC
RT
TGEN V_REF VC GND
0.1μF
1A
16.9k
1MHz
10μF
15μH
0.1μF
3517 TA01a
Efficiency
100
CTRL = V_REF
90
80
70
60
50
40
0
20
40
60
80 100
PWM DUTY CYCLE (%)
3517 TA01b
3517ff
1