LT3743 - High Current Synchronous Step-Down LED Driver with Three-State Control
Features
- PWM Dimming Provides Up to 3000:1 Dimming Ratio
- CTRL_SEL Dimming Provides Up to 3000:1 Dimming Ratio Between Any Current
- Three-State Current Control for Color Mixing
- ±6% Current Regulation Accuracy
- 6V to 36V Input Voltage Range
- Average Current Mode Control
- 2μs Maximum Recovery Time Between Any Current Regulation State
- <1μA Shutdown Current
- Output Voltage Regulation and Open-LED Protection
- Thermally Enhanced 4mm × 5mm QFN and 28-Pin FE Package
Typical Application
Description
The LT®3743 is a fixed frequency synchronous step-down DC/DC controller designed to drive high current LEDs. The average current mode controller will maintain inductor current regulation over a wide output voltage range of 0V to (VIN – 2V). LED dimming is achieved through analog dimming on the CTRL_L, CTRL_H and CTRL_T pins and with PWM dimming on the PWM and CTRL_SEL pins. Through the use of externally switched load capacitors, the LT3743 is capable of changing regulated LED current levels within several μs, providing accurate, high speed PWM dimming between two current levels. The switching frequency is programmable from 200kHz to 1MHz through an external resistor on the RT pin.
Additional features include voltage regulation and overvoltage protection set with a voltage divider from the output to the FB pin. Overcurrent protection is provided and set by the CTRL_H pin.
Packaging
CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.
For complete and up to date package information and drawings, please refer to our packaging page
| Part Number | Package | Code | Temp | Package Drawing |
RoHS |
|---|---|---|---|---|---|
| LT3743EFE#PBF | TSSOP-28 | FE | E | 05-08-1663 (EB) | Yes |
| LT3743EFE#TRPBF | TSSOP-28 | FE | E | 05-08-1663 (EB) | Yes |
| LT3743EUFD#PBF | 4x5 QFN-28 | UFD | E | 05-08-1712 | Yes |
| LT3743EUFD#TRPBF | 4x5 QFN-28 | UFD | E | 05-08-1712 | Yes |
| LT3743IFE#PBF | TSSOP-28 | FE | I | 05-08-1663 (EB) | Yes |
| LT3743IFE#TRPBF | TSSOP-28 | FE | I | 05-08-1663 (EB) | Yes |
| LT3743IUFD#PBF | 4x5 QFN-28 | UFD | I | 05-08-1712 | Yes |
| LT3743IUFD#TRPBF | 4x5 QFN-28 | UFD | I | 05-08-1712 | Yes |
Order Info
- Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
- Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
- Please refer to our general ordering information or the product datasheet for more details
Package Variations and Pricing
| Part Number | Package | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LT3743EFE#PBF | TSSOP-28 | E | $7.07 | $4.95 | Yes | |
| LT3743EFE#TRPBF | TSSOP-28 | E | $5.01 | Yes | ||
| LT3743EUFD#PBF | 4x5 QFN-28 | E | $6.86 | $4.80 | Yes | |
| LT3743EUFD#TRPBF | 4x5 QFN-28 | E | $4.86 | Yes | ||
| LT3743IFE#PBF | TSSOP-28 | I | $8.31 | $5.82 | Yes | |
| LT3743IFE#TRPBF | TSSOP-28 | I | $5.88 | Yes | ||
| LT3743IUFD#PBF | 4x5 QFN-28 | I | $8.07 | $5.65 | Yes | |
| LT3743IUFD#TRPBF | 4x5 QFN-28 | I | $5.71 | Yes | ||
| Buy Now • Request Samples | ||||||
Demo Boards
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 |
|---|---|---|---|
| DC1470A | LT3743EUF Demo Board | High Current Step-Down LED Driver Controller, 6.5V ≤ VIN ≤ 24V, VLED = 6V @ 20A | $175.00 | |
| Buy Now | |||
Applications
- DLP Projectors
- High Power Architectural Lighting
- Laser Diodes
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Design Tools
LTspice
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LT3743
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.
