LT3755/LT3755-1/LT3755-2
40V , 75V LED Controllers
IN OUT
FEATURES DESCRIPTION
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3000:1 True Color PWM Dimming The LT 3755, LT3755-1 and LT3755-2 are DC/DC control-
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Wide Input Voltage Range: 4.5V to 40V lers designed to operate as a constant-current source for
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Output Voltage Up to 75V driving high current LEDs. They drive a low side external
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Constant-Current and Constant-Voltage Regulation N-channel power MOSFET from an internal regulated 7.15V
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100mV High Side Current Sense supply. The fixed frequency, current mode architecture
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Drives LEDs in Boost, Buck Mode, Buck-Boost Mode, results in stable operation over a wide range of supply
SEPIC or Flyback Topology and output voltages. A ground referenced voltage FB pin
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Adjustable Frequency: 100kHz to 1MHz serves as the input for several LED protection features,
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Open LED Protection and also makes it possible for the converter to operate
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Programmable Undervoltage Lockout with Hysteresis as a constant-voltage source. A frequency adjust pin
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Improved Open LED Status Pin (LT3755-2) allows the user to program the frequency from 100kHz
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Frequency Synchronization (LT3755-1) to 1MHz to optimize efficiency, performance or external
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PWM Disconnect Switch Driver component size.
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CTRL Pin Provides Analog Dimming
The LT3755/LT3755-1/LT3755-2 sense output current at
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Low Shutdown Current: <1A
the high side of the LED string. High side current sensing
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Programmable Soft-Start
is the most flexible scheme for driving LEDs, allowing
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Thermally Enhanced 16-Lead QFN (3mm 3mm)
boost, buck mode or buck-boost mode configuration.
and MSOP Packages
The PWM input provides LED dimming ratios of up to
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AEC-Q100 Qualified For Automotive Applications
3000:1, and the CTRL input provides additional analog
dimming capability.
APPLICATIONS
All registered trademarks and trademarks are the property of their respective owners. Protected
by U.S. patents, including 7199560 and 7321203.
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High Power LED
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Battery Chargers
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Accurate Current Limited Voltage Regulators
TYPICAL APPLICATION
50W White Automotive LED Headlamp Driver
Efficiency vs V
IN
22H
V
IN
100
8V TO
40V
1M 4.7F
4.7F 1M
V
IN
SHDN/UVLO FB 96
V
REF
ISP
23.7k
185k
332k
LT3755-2
0.1 1A
92
CTRL
ISN
INTV
CC 40.2k
GATE
88
100k
SENSE
OPENLED
0.015
50W
PWM
LED
84
SS
STRING
PWMOUT
RT
V GND INTV
C CC
80
28.7k
0.01F
0 10 20 30 40
375kHz
10k 4.7F
V (V)
IN
0.001F
37551 TA01b
37551 TA01a
Rev. E
1
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EFFICIENCY (%)LT3755/LT3755-1/LT3755-2
(Note 1)
ABSOLUTE MAXIMUM RATINGS
V ............................................................................40V RT ............................................................................1.5V
IN
SHDN/UVLO (Note 3) ................................................40V SENSE ......................................................................0.5V
ISP, ISN .....................................................................75V Operating Junction Temperature Range (Notes 2, 5)
INTV ......................................................V + 0.3V, 8V LT3755E/LT3755I ...............................40C to 125C
CC IN
GATE, PWMOUT (Note 4) ......................... INTV + 0.3V LT3755H/LT3755J .............................40C TO 150C
CC
CTRL, PWM, OPENLED .............................................12V Storage Temperature Range ................... 65C to 150C
V , V , SS, FB ..........................................................3V Lead Temperature (Soldering, 10 sec)
C REF
SYNC ..........................................................................8V MSOP ............................................................... 300C
PIN CONFIGURATION
TOP VIEW
16 15 14 13
TOP VIEW
V 1 12 FB
REF
PWMOUT 1 16 GATE
FB 2 15 SENSE
PWM 2 11 PWMOUT
17
3
ISN 14 V
IN
GND
SYNC OR OPENLED 3 10 GATE
ISP 4 17 13 INTV
CC
5
VC GND 12 SHDN/UVLO
SS 4 9 SENSE
CTRL 6 11 RT
7
V 10 SS
5 6 7 8 REF
PWM 8 9 SYNC OR OPENLED
MSE PACKAGE
16-LEAD PLASTIC MSOP
T = 125C (E, I GRADES), T = 150C (H, J GRADES), = 43C/W, = 4C/W
JMAX JMAX JA JC
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
UD PACKAGE
16-LEAD (3mm 3mm) PLASTIC QFN
T = 125C, = 68C/W, = 4.2C/W
JMAX JA JC
EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB
ORDER INFORMATION
LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE
LT3755EUD#PBF LT3755EUD#TRPBF LDGC 16-Lead (3mm 3mm) Plastic QFN 40C to 125C
LT3755IUD#PBF LT3755IUD#TRPBF LDGC 16-Lead (3mm 3mm) Plastic QFN 40C to 125C
LT3755EUD-1#PBF LT3755EUD-1#TRPBF LDMS 16-Lead (3mm 3mm) Plastic QFN 40C to 125C
LT3755IUD-1#PBF LT3755IUD-1#TRPBF LDMS 16-Lead (3mm 3mm) Plastic QFN 40C to 125C
LT3755EUD-2#PBF LT3755EUD-2#TRPBF LFJZ 16-Lead (3mm 3mm) Plastic QFN 40C to 125C
LT3755IUD-2#PBF LT3755IUD-2#TRPBF LFJZ 16-Lead (3mm 3mm) Plastic QFN 40C to 125C
LT3755EMSE#PBF LT3755EMSE#TRPBF 3755 16-Lead Plastic MSOP 40C to 125C
LT3755IMSE#PBF LT3755IMSE#TRPBF 3755 16-Lead Plastic MSOP 40C to 125C
LT3755EMSE-1#PBF LT3755EMSE-1#TRPBF 37551 16-Lead Plastic MSOP 40C to 125C
LT3755IMSE-1#PBF LT3755IMSE-1#TRPBF 37551 16-Lead Plastic MSOP 40C to 125C
LT3755EMSE-2#PBF LT3755EMSE-2#TRPBF 37552 16-Lead Plastic MSOP 40C to 125C
LT3755IMSE-2#PBF LT3755IMSE-2#TRPBF 37552 16-Lead Plastic MSOP 40C to 125C
LT3755HMSE-2#PBF LT3755HMSE-2#TRPBF 37552 16-Lead Plastic MSOP 40C to 150C
LT3755JMSE-2#PBF LT3755JMSE-2#TRPBF 37552 16-Lead Plastic MSOP 40C to 150C
Rev. E
2
For more information www.analog.com
RT CTRL
SHDN/UVLO VC
INTV ISP
CC
V ISN
IN