LT3474/LT3474-1 - Step-Down 1A LED Driver
- True Color PWM Delivers Constant Color with 400:1 Dimming Range
- Wide Input Range: 4V to 36V
- Up to 1A LED Current
- Adjustable 200kHz–2MHz Switching Frequency
- Adjustable Control of LED Current
- Integrated Boost Diode
- High Output Current Accuracy is Maintained Over a Wide Range from 35mA to 1A
- Open LED (LT3474) and Short-Circuit Protection
- High Side Sense Allows Grounded Cathode Connection
- Uses Small Inductors and Ceramic Capacitors
- LT3474-1 Drives LED Strings Up to 26V
- Compact 16-Lead TSSOP Thermally Enhanced Surface Mount Package
AEC-Q100 data available for specific packages
The LT3474/LT3474-1 are fixed frequency step-down DC/DC converters designed to operate as constant-current sources. An internal sense resistor monitors the output current allowing accurate current regulation, ideal for driving high current LEDs. High output current accuracy is maintained over a wide current range, from 35mA to 1A, allowing a wide dimming range.
Unique PWM circuitry allows a dimming range of 400:1, avoiding the color shift normally associated with LED current dimming.
The high switching frequency offers several advantages, permitting the use of small inductors and ceramic capacitors. Small inductors combined with the 16 lead TSSOP surface mount package save space and cost versus alternative solutions. The constant switching frequency combined with low-impedance ceramic capacitors result in low, predictable output ripple.
With their wide input range of 4V to 36V, the LT3474/ LT3474-1 regulate a broad array of power sources, from 5V logic rails to unregulated wall transformers, lead acid batteries and distributed power supplies. A current mode PWM architecture provides fast transient response and cycle-by-cycle current limiting. Frequency foldback and thermal shutdown provide additional protection.
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 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
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Demo BoardsLinear 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.
|DC1309A||LT3474EFE-1 Demo Board | Buck LED Driver, 4 ≤ VIN ≤ 36V, VLED up to 26V @ 1A||$100.00|
|DC842A||LT3474EFE/IFE Demo Board | Step-Down LED Driver, 6V ≤ VIN ≤ 36V, VLED = 3.9V @ 1A||$100.00|
Designed for Automotive and Transportation ApplicationsAEC-Q100 data is available for these specific part numbers. Please contact your local sales representative for more information regarding reliability reports or to inquire about parts that are not included. For more information, view our Automotive and Transportation page
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- Automotive and Avionic Lighting
- Architectural Detail Lighting
- Display Backlighting
- Constant Current Sources
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