DocumentationDatasheet
Reliability Data
LT Journal
Article
Press Release
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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
Description
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.
3x3 QFN-16,MS-16E
Package Variations and Pricing
| Part Number | Package | Pins | Temp | Price (1-99) |
Price (1k)* |
|---|---|---|---|---|---|
| LT3755EMSE#PBF | MSOP | 16 | E | $4.07 | $2.85 |
| LT3755EMSE#TRPBF | MSOP | 16 | E | $2.91 | |
| LT3755EMSE-1#PBF | MSOP | 16 | E | $4.07 | $2.85 |
| LT3755EMSE-1#TRPBF | MSOP | 16 | E | $2.91 | |
| LT3755EMSE-2#PBF | MSOP | 16 | E | $4.07 | $2.85 |
| LT3755EMSE-2#TRPBF | MSOP | 16 | E | $2.91 | |
| LT3755EUD#PBF | QFN | 16 | E | $3.93 | $2.75 |
| LT3755EUD#TRPBF | QFN | 16 | E | $2.81 | |
| LT3755EUD-1#PBF | QFN | 16 | E | $3.93 | $2.75 |
| LT3755EUD-1#TRPBF | QFN | 16 | E | $2.81 | |
| LT3755EUD-2#PBF | QFN | 16 | E | $3.93 | $2.75 |
| LT3755EUD-2#TRPBF | QFN | 16 | E | $2.81 | |
| LT3755HMSE-2#PBF | MSOP | 16 | H | $5.00 | $3.50 |
| LT3755HMSE-2#TRPBF | MSOP | 16 | H | $3.56 | |
| LT3755IMSE#PBF | MSOP | 16 | I | $4.64 | $3.25 |
| LT3755IMSE#TRPBF | MSOP | 16 | I | $3.31 | |
| LT3755IMSE-1#PBF | MSOP | 16 | I | $4.64 | $3.25 |
| LT3755IMSE-1#TRPBF | MSOP | 16 | I | $3.31 | |
| LT3755IMSE-2#PBF | MSOP | 16 | I | $4.64 | $3.25 |
| LT3755IMSE-2#TRPBF | MSOP | 16 | I | $3.31 | |
| LT3755IUD#PBF | QFN | 16 | I | $4.50 | $3.15 |
| LT3755IUD#TRPBF | QFN | 16 | I | $3.21 | |
| LT3755IUD-1#PBF | QFN | 16 | I | $4.50 | $3.15 |
| LT3755IUD-1#TRPBF | QFN | 16 | I | $3.21 | |
| LT3755IUD-2#PBF | QFN | 16 | I | $4.50 | $3.15 |
| LT3755IUD-2#TRPBF | QFN | 16 | I | $3.21 |
Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.
| Part Number | Description | Price | Documentation |
|---|---|---|---|
| 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 |