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Analog Devices Inc. LT3741EFE-1#TRPBF
- Part No.:
- LT3741EFE-1#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 20-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3741EFE-1#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,282
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Product details
Overview
LT3741EFE-1#TRPBF from Analog Devices (formerly Linear Technology) is a fixed-frequency synchronous step-down DC/DC controller optimized for high-power constant-current and constant-voltage regulation up to 20A output. It features average current-mode control, ±6% current regulation accuracy, 6V–36V input range, and wide 0V to (VIN – 2V) output voltage capability - enabling precise LED driver, supercapacitor charging, and industrial power supply designs.
For engineers reviewing the LT3741EFE-1#TRPBF datasheet, LT3741EFE-1#TRPBF pinout, LT3741EFE-1#TRPBF application, or LT3741EFE-1#TRPBF equivalent, this page delivers verified technical context, real-world design parameters, thermal control integration, and validated alternative options for high-current buck controller selection.
Technical Context
The LT3741EFE-1#TRPBF implements average current-mode control with dual analog inputs (CTRL1/CTRL2) to set regulated output current, where the lower voltage determines final current limit. Its unique architecture supports both sourcing and sinking current in the LT3741 variant, while the -1 suffix denotes the LT3741-1 version optimized for unidirectional (source-only) operation and parallel configurations.
It integrates a 2V buffered reference (VREF), 1.21V FB reference with overvoltage lockout at 1.5V, soft-start via SS pin (11µA charge current), and programmable switching frequency (200kHz–1MHz) via RT resistor or SYNC input. Thermal shutdown activates at 163°C with 8°C hysteresis, and EN/UVLO provides precision enable with 1.55V threshold and 130mV hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6V to 36V - supports wide industrial input rails including 12V, 24V, and 36V systems without external pre-regulation. |
| Output Current Accuracy | ±6% - enables reliable current regulation for LED arrays and battery charging where tight current matching is critical. |
| Voltage Regulation Accuracy | ±1.5% - ensures stable output voltage under load transients and line variations for CV applications like precision power supplies. |
| Switching Frequency Range | 200kHz to 1MHz - allows trade-off between efficiency (lower fSW) and component size (higher fSW) in space-constrained designs. |
| Shutdown Quiescent Current | <1µA - minimizes standby power loss in always-on or energy-sensitive systems such as remote sensors and backup power modules. |
| Package | 20-Lead Plastic TSSOP - thermally enhanced surface-mount package compatible with standard reflow profiles and manual inspection. |
| Operating Junction Temp | –40°C to 125°C - qualified for harsh industrial and automotive under-hood environments without derating. |
Pinout & Package
LT3741EFE-1#TRPBF uses a 20-lead plastic TSSOP package with exposed pad (Pin 21 = GND). The exposed pad must be soldered to PCB for thermal performance and electrical grounding.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN/UVLO (Pin 4) | Enable / Undervoltage Lockout Input | Activates internal bias at 1.55V; full shutdown below ~0.5V; 130mV hysteresis enables programmable UVLO with external resistor divider. |
| VREF (Pin 5) | 2V Buffered Reference Output | Supplies up to 500µA; used to generate CTRL1/CTRL2 control voltages via resistor dividers for accurate current programming. |
| CTRL2 (Pin 6) | Thermal Control Input | Reduces regulated current when temperature rises; used with NTC thermistor network to implement active thermal derating. |
| CTRL1 (Pin 8) | Primary Current Set Input | Sets high-level regulated current (0–1.5V range → 0–51mV across sense resistor); clamped internally to prevent overrange. |
| SS (Pin 9) | Soft-Start Control | Charged by 11µA current source; controls ramp rate of regulated current during startup to limit inrush and stress on FETs/capacitors. |
| FB (Pin 10) | Voltage Feedback Input | 1.21V reference sets output voltage via resistor divider; overvoltage protection triggers at 1.5V (25% above regulation point). |
| SENSE+ (Pin 11) | Current Sense Inverting Input | Connects to high-side of external sense resistor; forms differential pair with SENSE– to measure inductor current accurately. |
| SENSE– (Pin 12) | Current Sense Non-Inverting Input | Reference current flows out to low-side of sense resistor; common-mode range extends to VIN – 2V for high-side sensing. |
| VC (Pin 13) | Current Loop Compensation | Connects to compensation network (typically 20kΩ–50kΩ + 2nF–5nF) to stabilize average current-mode control loop. |
| RT (Pin 14) | Frequency Setting Input | Resistor to GND sets switching frequency; 40kΩ yields ~1MHz; current-limited to 60µA to prevent damage if shorted. |
| SYNC (Pin 15) | External Clock Synchronization | Accepts external clock signal; internal oscillator must be set 20% slower than SYNC frequency to avoid jitter or loss of lock. |
| HG (Pin 17) | High-Side Gate Driver Output | Drives external high-side N-channel MOSFET; pull-up/pull-down impedances are 2.3Ω/1.3Ω for fast switching and low gate loss. |
| LG (Pin 20) | Low-Side Gate Driver Output | Drives external low-side N-channel MOSFET; pull-up/pull-down impedances are 2.3Ω/1.0Ω for efficient turn-on/turn-off. |
| VIN (Pin 3) | Main Power Input | Accepts 6V–36V input; requires local 4.7µF low-ESR ceramic bypass capacitor to minimize noise and supply impedance. |
| VCC_INT (Pin 1) | Internal 5V Regulator Output | Provides 5V for CBOOT charging and internal circuitry; current-limited to 50mA; disable during shutdown. |
Key Features
| Feature | Design Value |
|---|---|
| Dual analog current control (CTRL1/CTRL2) | Enables independent thermal derating (via CTRL2) while maintaining primary current setpoint (CTRL1), supporting robust overtemperature protection without disabling regulation. |
| Average current-mode architecture | Delivers stable, ripple-insensitive current regulation across wide output voltage ranges - essential for LED drivers and supercapacitor charging where VOUT varies significantly. |
| Programmable overvoltage lockout (OVL) | Shuts down switching for 13µs when FB exceeds 1.5V, allowing safe inductor current discharge and preventing output overshoot during fault conditions. |
| Accurate 2V reference (VREF) | Stable, buffered 2V output with ±1% tolerance enables precise, temperature-invariant current programming using simple resistor dividers on CTRL1/CTRL2. |
| Thermally enhanced TSSOP package | 20-lead TSSOP with exposed pad achieves θJA = 38°C/W - enabling 20A operation with minimal heatsinking in compact industrial PCB layouts. |
Applications
| LED Constant-Current Driver | Supercapacitor Charging System |
|---|---|
|
Use Scenario: Driving high-brightness LED strings in industrial lighting or automotive exterior lamps requiring precise current matching and thermal foldback. IC Role / Device Role / Timing Role: Primary current-regulating buck controller; senses inductor current via external shunt and adjusts duty cycle to maintain constant average current regardless of forward voltage drift. Use Value: ±6% current accuracy ensures uniform luminance across LED arrays; CTRL2-based thermal derating prevents LED thermal runaway at elevated ambient temperatures. |
Use Scenario: Charging large supercapacitor banks (e.g., 50F–500F) from 12V/24V sources in energy harvesting or backup power systems. IC Role / Device Role / Timing Role: High-current step-down controller operating in constant-current mode until capacitor voltage reaches target, then transitions to constant-voltage regulation. Use Value: Wide 0V–(VIN–2V) output range enables full-capacity charging from 0V; soft-start prevents inrush damage; OVL protects against overvoltage during charge termination. |
| Industrial Precision Power Supply | High-Current Test Equipment Source |
|
Use Scenario: Programmable bench power supply or system power rail delivering up to 20A with simultaneous CC/CV operation and remote sensing. IC Role / Device Role / Timing Role: Core buck controller implementing dual-loop regulation - current loop dominates during short-circuit or startup; voltage loop engages once VOUT reaches setpoint. Use Value: ±1.5% voltage accuracy and ±6% current accuracy meet lab-grade requirements; SYNC pin enables multi-rail phase interleaving for reduced input ripple. |
Use Scenario: Automated test equipment (ATE) requiring programmable, high-stability current/voltage sources for DUT characterization and burn-in testing. IC Role / Device Role / Timing Role: Reconfigurable power stage controller accepting analog setpoints (CTRL1/CTRL2) and digital enable (EN/UVLO) for automated test sequencing. Use Value: Fast transient response (<100µs recovery per G34/G35 curves) ensures stable loading during dynamic DUT current steps; <1µA shutdown current enables low-power standby modes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-current buck controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3775 | Single-phase, 2-phase capable controller; supports up to 60A with external MOSFETs; no integrated thermal control input (CTRL2); requires external current-sense amplifier. | Better suited for higher-current (>20A), multi-phase, or digitally controlled systems; lacks native thermal foldback function. | Select LTC3775 when scaling beyond 20A or requiring phase interleaving; use LT3741EFE-1#TRPBF when thermal derating and analog simplicity are priorities. |
| LM5119 | Fixed-frequency current-mode controller; 3.5V–65V input; ±3% current accuracy; no CTRL2 pin; only single analog current set input (COMP). | Designed for wider input range and higher voltage industrial applications; less precise current regulation and no dedicated thermal control path. | Choose LM5119 for 48V bus systems or where input exceeds 36V; retain LT3741EFE-1#TRPBF for ≤36V, 20A, and integrated thermal management. |
Compared with LTC3775 and LM5119, the LT3741EFE-1#TRPBF uniquely combines ±6% current accuracy, dual analog control (CTRL1/CTRL2), and native thermal foldback in a compact TSSOP package - making it optimal for space-constrained, thermally sensitive 20A CC/CV applications where simplicity and reliability outweigh ultra-high-current scalability.
Availability
LT3741EFE-1#TRPBF is available at Aetrix Electronics and suitable for industrial power supplies, LED driver modules, supercapacitor charging systems, and automated test equipment requiring stable component supply and long-term production continuity.
Supply support for LT3741EFE-1#TRPBF includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Analog Devices (ADI) is a global leader in high-performance analog, mixed-signal, and power management ICs, formed through the acquisition of Linear Technology in 2017.
The LT3741 product line was developed by Linear Technology specifically for high-accuracy, high-current constant-current and constant-voltage step-down applications - targeting LED lighting, energy storage, and precision industrial power conversion.
FAQ
What is the key functional difference between LT3741EFE-1#TRPBF and the base LT3741EFE#TRPBF?
The LT3741EFE-1#TRPBF is the LT3741-1 variant, optimized for unidirectional (source-only) current operation and parallel controller configurations. Unlike the LT3741EFE#TRPBF, which supports bidirectional current (sourcing and sinking), the -1 version removes zero-cross detection circuitry - simplifying design for applications like LED drivers and supercapacitor chargers where sinking current is unnecessary. This improves efficiency and reduces complexity in single-direction high-current buck topologies.
Can LT3741EFE-1#TRPBF regulate output voltage independently of current regulation?
Yes, the LT3741EFE-1#TRPBF implements dual-loop regulation: the current loop dominates during startup and overload, while the voltage loop engages once the output reaches the level set by the FB resistor divider (1.21V reference). When VOUT rises to the programmed level, the controller reduces inductor current to maintain constant voltage - enabling seamless transition between constant-current and constant-voltage modes without external intervention.
What is the maximum supported output current for LT3741EFE-1#TRPBF in practice?
The LT3741EFE-1#TRPBF is designed to regulate up to 20A output current, as confirmed by its ±6% current regulation specification, thermal shutdown threshold (163°C), and typical application circuits (e.g., TA01a shows 10V/20A operation). Real-world capability depends on external components - especially MOSFET RDS(ON), inductor saturation current, and PCB copper area - but 20A is the validated, datasheet-guaranteed maximum under specified thermal conditions.
How does the CTRL2 pin provide thermal control in LT3741EFE-1#TRPBF?
The CTRL2 pin accepts an analog voltage that competes with CTRL1 to determine final current limit - the lower of the two voltages wins. By connecting a thermistor-based voltage divider to CTRL2, designers can reduce the control voltage as temperature rises, thereby lowering the regulated output current before thermal shutdown occurs. This enables graceful, programmable thermal derating - preserving system uptime while protecting LEDs, capacitors, and MOSFETs from overheating.
Is LT3741EFE-1#TRPBF pin-compatible with other LT3741 variants in the same package?
Yes, the LT3741EFE-1#TRPBF shares identical pinout and package (20-lead TSSOP) with LT3741EFE#TRPBF, LT3741IFE-1#TRPBF, and other FE-package variants. All share the same pin configuration shown in the FE PACKAGE TOP VIEW diagram (page 2 of datasheet 37411fg), including identical pin numbering, functions, and absolute maximum ratings - enabling drop-in replacement within the same temperature grade and package type.
LT3741EFE-1#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Output Type:
- Transistor Driver
- Function:
- Step-Down
- Output Configuration:
- Positive
- Topology:
- Buck
- Number of Outputs:
- 1
- Output Phases:
- 1
- Voltage - Supply (Vcc/Vdd):
- 6V ~ 36V
- Frequency - Switching:
- 200kHz ~ 1MHz
- Duty Cycle (Max):
- -
- Synchronous Rectifier:
- Yes
- Clock Sync:
- Yes
- Serial Interfaces:
- -
- Control Features:
- Enable, Frequency Control, Soft Start
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP-EP
LT3741EFE-1#TRPBF FAQ
1.How can I place an order for LT3741EFE-1#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3741EFE-1#TRPBF on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LT3741EFE-1#TRPBF reliable?
The price and inventory of LT3741EFE-1#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3741EFE-1#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3741EFE-1#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3741EFE-1#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3741EFE-1#TRPBF?
LT3741EFE-1#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3741EFE-1#TRPBF order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LT3741EFE-1#TRPBF?
For technical support, including LT3741EFE-1#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3741EFE-1#TRPBF requirements.
6.How does Aetrix verify that LT3741EFE-1#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3741EFE-1#TRPBF products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LT3741EFE-1#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3741EFE-1#TRPBF?
All LT3741EFE-1#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3741EFE-1#TRPBF, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LT3741EFE-1#TRPBF part is unused and in its original packaging.
Return procedure for LT3741EFE-1#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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