LT3741
LT3741-1
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LT3741
LT3741-1

High Power, Constant Current, Constant Voltage, Step-Down Controller

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Info: : PRODUCTION tooltip
Info: : PRODUCTION tooltip
Part Details
Part Models 16
1ku List Price Starting From $4.72
Features
  • Control Pin Provides Accurate Control of Regulated Output Current
  • ±1.5% Voltage Regulation Accuracy
  • ±6% Current Regulation Accuracy
  • 6V to 36V Input Voltage Range
  • Wide Output Voltage Range Up to (VIN – 2V)
  • Average Current Mode Control
  • <1μA Shutdown Current
  • Up to 94% Efficiency
  • Additional Pin for Thermal Control of Load Current
  • Thermally Enhanced 4mm × 4mm QFN and 20-Pin FE Package
Additional Details
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The LT3741 and LT3741-1 are fixed frequency synchronous step-down DC/DC controllers designed to accurately regulate the output current at up to 20A. The average current-mode controller will maintain inductor current regulation over a wide output voltage range of 0V to (VIN – 2V). The regulated current is set by an analog voltage on the CTRL pins and an external sense resistor. Due to its unique topology, the LT3741 is capable of sourcing and sinking current. If sinking current is not required, or for parallel applications, use the LT3741-1. The regulated voltage and overvoltage protection are set with a voltage divider from the output to the FB pin. Soft-Start is provided to allow a gradual increase in the regulated current during startup. The switching frequency is programmable from 200kHz to 1MHz through an external resistor on the RT pin or through the use of the SYNC pin and an external clock signal.

Additional Features include an accurate external reference voltage for use with the CTRL pins, an accurate UVLO/EN pin that allows for programmable UVLO hysteresis, and thermal shutdown.

Applications

  • General Purpose Industrial
  • Super-Cap Charging
  • Applications Needing Extreme Short-Circuit Protection and/or Accurate Output Current Limit
  • Constant Current or Constant Voltage Source
Part Models 16
1ku List Price Starting From $4.72

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Documentation

Documentation

Part Model Pin/Package Drawing Documentation CAD Symbols, Footprints, and 3D Models
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Product Lifecycle

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Apr 6, 2022

- 22_0068

Laser Top Mark for ETSSOP and TSSOP Packages Assembled in ADPG [PNG] and UTL

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Jan 20, 2022

- 21_0269

Addition of Alternate Assembly Site ASE Taiwan for Select LFCSP Products

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Apr 6, 2022

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Laser Top Mark for ETSSOP and TSSOP Packages Assembled in ADPG [PNG] and UTL

LT3741EFE#PBF

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LT3741EFE#TRPBF

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LT3741EFE-1#PBF

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LT3741EFE-1#TRPBF

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LT3741IFE#PBF

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LT3741IFE#TRPBF

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LT3741IFE-1#TRPBF

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Jan 20, 2022

- 21_0269

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Addition of Alternate Assembly Site ASE Taiwan for Select LFCSP Products

LT3741EUF#PBF

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LT3741EUF#TRPBF

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Software & Part Ecosystem

Software & Part Ecosystem

Evaluation Kit

Evaluation Kits 1

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DC1602A

LT3741EFE Demo Board | 120W LED Driver, 12V ≤ VIN ≤ 24V, CC/CV Synchronous Step-Down Controller, VOUT = 6V @ 20A

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DC1602A

LT3741EFE Demo Board | 120W LED Driver, 12V ≤ VIN ≤ 24V, CC/CV Synchronous Step-Down Controller, VOUT = 6V @ 20A

LT3741EFE Demo Board | 120W LED Driver, 12V ≤ VIN ≤ 24V, CC/CV Synchronous Step-Down Controller, VOUT = 6V @ 20A

Product Detail

Demonstration circuit 1602 is a High Power Constant Current, Constant Voltage Synchronous Buck Controller featuring the LT3741. The demo board is optimized for 20A output from a 12V input. Being an LED driver, the output current is being regulated until the output voltage reaches a programmed voltage limit. The voltage limit on this demo board is set to around 6V by R11 and R14. The 6V is chosen because of the 10V voltage rating of the output capacitors. Higher output voltage can be easily achieved with higher voltage rated output capacitors.


The ideal load to be used with this demo board is a single LED, such as PT120 from Luminus Devices. Smaller LEDs may not be able to handle the high current, even for a short period of time. At 20A, the demo circuit can operate continuously. However, it is necessary to mount the LED load on a proper heat sink and possibly with a fan to avoid exceed its maximum temperate rating.

Tools & Simulations

Tools & Simulations 1

LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.

To launch ready-to-run LTspice demonstration circuits for this part:

Step 1: Download and install LTspice on your computer.

Step 2: Click on the link in the section below to download a demonstration circuit.

Step 3: If LTspice does not automatically open after clicking the link below, 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 demonstration circuit by selecting ‘Open’ from the ‘File’ menu.

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