LT3755/LT3755-1/LT3755-2 - 40VIN, 75VOUT LED Controllers
The LT3755, LT3755-1 and LT3755-2 are DC/DC controllers designed to operate as a constant-current source for driving high current LEDs. They drive a low side external N-channel power MOSFET from an internal regulated 7.15V supply. The fixed frequency, current mode architecture results in stable operation over a wide range of supply and output voltages. A ground referenced voltage FB pin serves as the input for several LED protection features, and also makes it possible for the converter to operate as a constant-voltage source. A frequency adjust pin allows the user to program the frequency from 100kHz to 1MHz to optimize efficiency, performance or external component size.
The LT3755/LT3755-1/LT3755-2 sense output current at the high side of the LED string. High side current sensing is the most flexible scheme for driving LEDs, allowing boost, buck mode or buck-boost mode configuration. The PWM input provides LED dimming ratios of up to 3000:1, and the CTRL input provides additional analog dimming capability.
Features- 3000:1 True Color PWM™ Dimming
- Wide Input Voltage Range: 4.5V to 40V
- Output Voltage Up to 75V
- Constant-Current and Constant-Voltage Regulation
- 100mV High Side Current Sense
- Drives LEDs in Boost, Buck Mode, Buck-Boost Mode, SEPIC or Flyback Topology
- Adjustable Frequency: 100kHz to 1MHz
- Open LED Protection
- Programmable Undervoltage Lockout with Hysteresis
- Improved Open LED Status Pin (LT3755-2)
- Frequency Synchronization (LT3755-1)
- PWM Disconnect Switch Driver
- CTRL Pin Provides Analog Dimming
- Low Shutdown Current: <1μA
- Programmable Soft-Start
- Thermally Enhanced 16-Lead QFN (3mm × 3mm) and MSOP Packages
- For new designs we recommend the LT3755-2 instead of the LT3755
Typical Application
 | Applications- High Power LED
- Battery Chargers
- Accurate Current Limited Voltage Regulators
Packaging
 |
Order Information| Part Number | Package | Temp | Price(1-99) | Price (1k)* |
|---|
| LT3755EMSE-1#PBF | MS-16E | E | $4.07 | $2.85 |
| LT3755EMSE-1#TRPBF | MS-16E | E | | $2.91 |
| LT3755EMSE-2#PBF | MS-16E | E | $4.07 | $2.85 |
| LT3755EMSE-2#TRPBF | MS-16E | E | | $2.91 |
| LT3755EMSE#PBF | MS-16E | E | $4.07 | $2.85 |
| LT3755EMSE#TRPBF | MS-16E | E | | $2.91 |
| LT3755EUD-1#PBF | 3x3 QFN-16 | E | $3.93 | $2.75 |
| LT3755EUD-1#TRPBF | 3x3 QFN-16 | E | | $2.81 |
| LT3755EUD-2#PBF | 3x3 QFN-16 | E | $3.93 | $2.75 |
| LT3755EUD-2#TRPBF | 3x3 QFN-16 | E | | $2.81 |
| LT3755EUD#PBF | 3x3 QFN-16 | E | $3.93 | $2.75 |
| LT3755EUD#TRPBF | 3x3 QFN-16 | E | | $2.81 |
| LT3755HMSE-2#PBF | MS-16E | H | $5.00 | $3.50 |
| LT3755HMSE-2#TRPBF | MS-16E | H | | $3.56 |
| LT3755IMSE-1#PBF | MS-16E | I | $4.64 | $3.25 |
| LT3755IMSE-1#TRPBF | MS-16E | I | | $3.31 |
| LT3755IMSE-2#PBF | MS-16E | I | $4.64 | $3.25 |
| LT3755IMSE-2#TRPBF | MS-16E | I | | $3.31 |
| LT3755IMSE#PBF | MS-16E | I | $4.64 | $3.25 |
| LT3755IMSE#TRPBF | MS-16E | I | | $3.31 |
| LT3755IUD-1#PBF | 3x3 QFN-16 | I | $4.50 | $3.15 |
| LT3755IUD-1#TRPBF | 3x3 QFN-16 | I | | $3.21 |
| LT3755IUD-2#PBF | 3x3 QFN-16 | I | $4.50 | $3.15 |
| LT3755IUD-2#TRPBF | 3x3 QFN-16 | I | | $3.21 |
| LT3755IUD#PBF | 3x3 QFN-16 | I | $4.50 | $3.15 |
| LT3755IUD#TRPBF | 3x3 QFN-16 | I | | $3.21 |
Demo Boards
| Part Number | Description | Price |
|---|
| DC1268B-A | LT3755EUD-2 Demo Board | Boost LED Driver Controller, 8V ≤ VIN ≤ 40V, VLED up to 54V @ 1A | $175.00 |
| DC1268B-B | LT3755EUD-1 Demo Board | Boost LED Driver Controller, 8V ≤ VIN ≤ 40V, VLED up to 54V @ 1A | $175.00 |
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