LT3746 - 32-Channel 20mA LED Driver with Buck Controller


  • 6V to 55V Power Input Voltage Range
  • 32 Independent LED Outputs up to 30mA/13V
  • 6-Bit Dot Correction Current Adjustment
  • 12-Bit Grayscale PWM Dimming
  • 0.5μs Minimum LED On Time
  • Adaptive LED Bus Voltage for High Efficiency
  • Cascadable 30MHz Serial Data Interface
  • Full Diagnostic and Protection: Individual Open/Short LED and Overtemperature Fault

Typical Application

LT3746 Typical Application


The LT®3746 integrates a 32-channel LED driver with a 55V buck controller. The LED driver lights up to 30mA/13V of LEDs in series per channel, and the buck controller generates an adaptive bus voltage supplying the parallel LED strings. Each channel has individual 6-bit dot correction current adjustment and 12-bit grayscale PWM dimming. Both dot correction and grayscale are accessible via a serial data interface in TTL/CMOS logic.

The LT3746 performs full diagnostic and protection against open/short LED and overtemperature fault. The fault status is sent back through the serial data interface. The 30MHz fully-buffered, skew-balanced, cascadable serial data interface makes the chip extremely suitable for large screen LCD dynamic backlighting and mono-, multi-, full-color LED displays.


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
LT3746EUHH#PBF 5x9 QFN-56 UHH E 05-08-1727 Yes
LT3746EUHH#TRPBF 5x9 QFN-56 UHH E 05-08-1727 Yes
LT3746IUHH#PBF 5x9 QFN-56 UHH I 05-08-1727 Yes
LT3746IUHH#TRPBF 5x9 QFN-56 UHH I 05-08-1727 Yes

LT3746 Package Drawing

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
LT3746EUHH#PBF 5x9 QFN-56 E $7.07 $4.95 Yes
LT3746EUHH#TRPBF 5x9 QFN-56 E $5.01 Yes
LT3746IUHH#PBF 5x9 QFN-56 I $7.79 $5.45 Yes
LT3746IUHH#TRPBF 5x9 QFN-56 I $5.51 Yes
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* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

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
DC1406A LT3746EUHH Demo Board | 32-Channel 20mA LED Driver (x3 for RGB), 9V ≤ VIN ≤ 40V, VLED up to 4.2V @ 20mA Contact Factory
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Companion Boards

Part Number Description Price Documentation
DC590B Isolated USB Serial Controller for Linear Technology QuikEval-Compatible Demo Boards $50.00
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Click here to view our complete list of demo boards


  • Large Screen Display LED Backlighting
  • Mono-, Multi-, Full-Color LED Displays
  • LED Billboards and Signboards

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Design Tools

Linear Technology provides a variety of custom design simulation tools and device models to allow even novice designers to quickly and easily evaluate circuits using high performance switching regulators, amplifiers, data converters, filters and more. Please visit our Design Tools page to view and download:

  • LTspice - A powerful SPICE simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators
  • LTpowerCAD - A complete power supply selection, synthesis and design tool
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  • PScope & QuikEval - USB-based product demonstration and data acquisition system for use with our ADCs, DACs, and more
  • Linduino - Arduino compatible system for developing and distributing firmware libraries and example code
  • LinearLab Tools - A collection of Matlab and Python programs that provide direct access to Linear Technology’s data converter evaluation boards
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