LT3741/LT3741-1 - High Power, Constant Current, Constant Voltage, Step-Down Controller
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
Typical Application
Description
The LT®3741 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 currentmode 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.
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 |
|---|---|---|---|---|---|
| LT3741EFE-1#PBF | TSSOP-20 | FE | E | 05-08-1663 (CB) | Yes |
| LT3741EFE-1#TRPBF | TSSOP-20 | FE | E | 05-08-1663 (CB) | Yes |
| LT3741EFE#PBF | TSSOP-20 | FE | E | 05-08-1663 (CB) | Yes |
| LT3741EFE#TRPBF | TSSOP-20 | FE | E | 05-08-1663 (CB) | Yes |
| LT3741EUF-1#PBF | 4x4 QFN-20 | UF | E | 05-08-1710 | Yes |
| LT3741EUF-1#TRPBF | 4x4 QFN-20 | UF | E | 05-08-1710 | Yes |
| LT3741EUF#PBF | 4x4 QFN-20 | UF | E | 05-08-1710 | Yes |
| LT3741EUF#TRPBF | 4x4 QFN-20 | UF | E | 05-08-1710 | Yes |
| LT3741IFE-1#PBF | TSSOP-20 | FE | I | 05-08-1663 (CB) | Yes |
| LT3741IFE-1#TRPBF | TSSOP-20 | FE | I | 05-08-1663 (CB) | Yes |
| LT3741IFE#PBF | TSSOP-20 | FE | I | 05-08-1663 (CB) | Yes |
| LT3741IFE#TRPBF | TSSOP-20 | FE | I | 05-08-1663 (CB) | Yes |
| LT3741IUF-1#PBF | 4x4 QFN-20 | UF | I | 05-08-1710 | Yes |
| LT3741IUF-1#TRPBF | 4x4 QFN-20 | UF | I | 05-08-1710 | Yes |
| LT3741IUF#PBF | 4x4 QFN-20 | UF | I | 05-08-1710 | Yes |
| LT3741IUF#TRPBF | 4x4 QFN-20 | UF | I | 05-08-1710 | 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 | |
|---|---|---|---|---|---|---|
| LT3741EFE-1#PBF | TSSOP-20 | E | $5.86 | $4.10 | Yes | |
| LT3741EFE-1#TRPBF | TSSOP-20 | E | $4.16 | Yes | ||
| LT3741EFE#PBF | TSSOP-20 | E | $5.86 | $4.10 | Yes | |
| LT3741EFE#TRPBF | TSSOP-20 | E | $4.16 | Yes | ||
| LT3741EUF-1#PBF | 4x4 QFN-20 | E | $5.64 | $3.95 | Yes | |
| LT3741EUF-1#TRPBF | 4x4 QFN-20 | E | $4.01 | Yes | ||
| LT3741EUF#PBF | 4x4 QFN-20 | E | $5.64 | $3.95 | Yes | |
| LT3741EUF#TRPBF | 4x4 QFN-20 | E | $4.01 | Yes | ||
| LT3741IFE-1#PBF | TSSOP-20 | I | $6.89 | $4.82 | Yes | |
| LT3741IFE-1#TRPBF | TSSOP-20 | I | $4.88 | Yes | ||
| LT3741IFE#PBF | TSSOP-20 | I | $6.89 | $4.82 | Yes | |
| LT3741IFE#TRPBF | TSSOP-20 | I | $4.88 | Yes | ||
| LT3741IUF-1#PBF | 4x4 QFN-20 | I | $6.64 | $4.65 | Yes | |
| LT3741IUF-1#TRPBF | 4x4 QFN-20 | I | $4.71 | Yes | ||
| LT3741IUF#PBF | 4x4 QFN-20 | I | $6.64 | $4.65 | Yes | |
| LT3741IUF#TRPBF | 4x4 QFN-20 | I | $4.71 | 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 |
|---|---|---|---|
| DC1602A | LT3741EFE Demo Board | 120W LED Driver, 12V ≤ VIN ≤ 24V, CC/CV Synchronous Step-Down Controller, Vout = 6V @ 20A | $175.00 | |
| Buy Now | |||
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
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Design Tools
LTspice
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LT3741
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.
