VideosDocumentationDatasheet
Design Note
Reliability Data
LT Journal
- January 2009 - 100V Controller in 3mm × 3mm QFN or MSE Drives High Power LED Strings from Just About Any Input
- March 2009 - Don’t Want to Hear It? Avoid the Audio Band with PWM LED Dimming at Frequencies Above 20kHz
Press Release
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ltspice
- LT3756 Demo Circuit - 100Vin 100Vout LED Driver Controller (8-80V to 24x 3.4V LEDs @ 500mA)
- LT3756-1 Demo Circuit - 100Vin 100Vout LED Driver Controller with Sync (8-80V to 24x 3.4V LEDs @ 500mA)
- LT3756-2 Demo Circuit - 30W White LED Automotive Headlamp Driver with Thermal Derating & Open LED Status (8-60V to 18x 3.4V LEDs @ 380mA)
- LT3756-2 Demo Circuit - Buck Mode 1A LED Driver with High Dimming Ratio and Open LED (24-80V to 1A/5 White LEDs)
Features
- 3000:1 True Color PWM™ Dimming
- Wide Input Voltage Range: 6V to 100V
- Output Voltage Up to 100V
- 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 (LT3756-2)
- Frequency Synchronization (LT3756-1)
- 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
Typical Application
Description
The LT3756, LT3756-1 and LT3756-2 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 LT3756/LT3756-1/LT3756-2 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)* |
|---|---|---|---|---|---|
| LT3756EMSE#PBF | MSOP | 16 | E | $4.29 | $3.00 |
| LT3756EMSE#TRPBF | MSOP | 16 | E | $3.06 | |
| LT3756EMSE-1#PBF | MSOP | 16 | E | $4.29 | $3.00 |
| LT3756EMSE-1#TRPBF | MSOP | 16 | E | $3.06 | |
| LT3756EMSE-2#PBF | MSOP | 16 | E | $4.29 | $3.00 |
| LT3756EMSE-2#TRPBF | MSOP | 16 | E | $3.06 | |
| LT3756EUD#PBF | QFN | 16 | E | $4.14 | $2.90 |
| LT3756EUD#TRPBF | QFN | 16 | E | $2.96 | |
| LT3756EUD-1#PBF | QFN | 16 | E | $4.14 | $2.90 |
| LT3756EUD-1#TRPBF | QFN | 16 | E | $2.96 | |
| LT3756EUD-2#PBF | QFN | 16 | E | $4.14 | $2.90 |
| LT3756EUD-2#TRPBF | QFN | 16 | E | $2.96 | |
| LT3756HMSE-2#PBF | MSOP | 16 | H | $5.22 | $3.65 |
| LT3756HMSE-2#TRPBF | MSOP | 16 | H | $3.71 | |
| LT3756IMSE#PBF | MSOP | 16 | I | $4.86 | $3.40 |
| LT3756IMSE#TRPBF | MSOP | 16 | I | $3.46 | |
| LT3756IMSE-1#PBF | MSOP | 16 | I | $4.86 | $3.40 |
| LT3756IMSE-1#TRPBF | MSOP | 16 | I | $3.46 | |
| LT3756IMSE-2#PBF | MSOP | 16 | I | $4.86 | $3.40 |
| LT3756IMSE-2#TRPBF | MSOP | 16 | I | $3.46 | |
| LT3756IUD#PBF | QFN | 16 | I | $4.71 | $3.30 |
| LT3756IUD#TRPBF | QFN | 16 | I | $3.36 | |
| LT3756IUD-1#PBF | QFN | 16 | I | $4.71 | $3.30 |
| LT3756IUD-1#TRPBF | QFN | 16 | I | $3.36 | |
| LT3756IUD-2#PBF | QFN | 16 | I | $4.71 | $3.30 |
| LT3756IUD-2#TRPBF | QFN | 16 | I | $3.36 |
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 |
|---|---|---|---|
| DC1319B-A | LT3756EMSE-2 Demo Board | Boost LED Driver Controller, 8V ≤ VIN ≤ 80V, VLED = 80V @ 0.5A | $210.00 | |
| DC1319B-B | LT3756EMSE-1 Demo Board | Boost LED Driver Controller, 8V ≤ VIN ≤ 80V, VLED up to 80V @ 0.5A | $210.00 |