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LT3755/LT3755-1 - 40VIN, 75VOUT LED Controller

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
  • Open LED Status Pin (LT3755)
  • 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

Typical Application

LT3755
LT3755
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Description

The LT®3755 and LT3755-1 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 7V 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 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. Both parts are available in the 16-lead (3mm × 3mm) QFN and MSOP packages.
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Packaging

QFN-16

LT3755
LT3755
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Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price (1-99) Price (1k)* RoHS Data
LT3755EMSE#PBF MSOP 16 E $4.07 $2.85 View
LT3755EMSE#TRPBF MSOP 16 E   $2.91 View
LT3755EMSE-1#PBF MSOP 16 E $4.07 $2.85 View
LT3755EMSE-1#TRPBF MSOP 16 E   $2.91 View
LT3755EUD#PBF QFN 16 E $3.93 $2.75 View
LT3755EUD#TRPBF QFN 16 E   $2.81 View
LT3755EUD-1#PBF QFN 16 E $3.93 $2.75 View
LT3755EUD-1#TRPBF QFN 16 E   $2.81 View
LT3755IMSE#PBF MSOP 16 I $4.64 $3.25 View
LT3755IMSE#TRPBF MSOP 16 I   $3.31 View
LT3755IMSE-1#PBF MSOP 16 I $4.64 $3.25 View
LT3755IMSE-1#TRPBF MSOP 16 I   $3.31 View
LT3755IUD#PBF QFN 16 I $4.50 $3.15 View
LT3755IUD#TRPBF QFN 10 I   $3.21 View
LT3755IUD-1#PBF QFN 16 I $4.50 $3.15 View
LT3755IUD-1#TRPBF QFN 16 I   $3.21 View
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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.

Evaluation Kits

Part Number Description Price
DC1268A-A LT3755EUD | 40V/75V Full-Featured LED Controller $175.00
DC1268A-B LT3755EUD-1 | 40V/75V Full-Featured LED Controller $175.00
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Applications

  • High Power LED Applications
  • Industrial
  • Automotive
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Simulate

LTSpice IV is a powerful FREE circuit simulator and schematic capture program, providing macro models for 80% of Linear Technology's switching regulators, over 200 op amp models, as well as resistors, transistors and MOSFET models.

  • Step 1. If you do not already have a copy of LTSpice, click here to download and install LTSpice IV

  • Step 2. Once LTSpice is installed, click here for a ready to run  demonstration circuit of the LT3755 or run
     demonstration circuit of the LT3755-1.

  • Step 3. If LTspice IV does not automatically open after clicking the above link, you can instead run the simulation by right clicking on the link and selecting “Save Target As”. After saving the file to your computer, start LTSpice and open the demonstartion circuit by selecting "Open" from the "File" menu.
For our complete list of hundreds of ready to run demo circuits, visit our LTspice IV Demo Circuits Collection
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