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Analog Devices Inc. LT3741EUF#TRPBF
- Part No.:
- LT3741EUF#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 20-WFQFN Exposed Pad
- Datasheet:
-
LT3741EUF#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 20QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,863
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Product details
Overview
LT3741EUF#TRPBF from Analog Devices (formerly Linear Technology) is a fixed-frequency synchronous step-down DC/DC controller designed for high-precision constant-current and constant-voltage regulation up to 20A output. It features average current-mode control, ±6% current regulation accuracy, ±1.5% voltage regulation accuracy, and supports 6V–36V input with output down to 0V (up to VIN – 2V). It is used in super-capacitor charging and industrial power supplies requiring extreme short-circuit protection.
For engineers reviewing the LT3741EUF#TRPBF datasheet, LT3741EUF#TRPBF pinout, LT3741EUF#TRPBF application, or LT3741EUF#TRPBF equivalent, key selection criteria include its dual CTRL pin current programming, thermal control via CTRL2, programmable switching frequency (200kHz–1MHz), and ability to source/sink current - distinguishing it from the LT3741-1 variant.
Technical Context
The LT3741EUF#TRPBF implements average current-mode control using internal gm amplifiers (475 µA/V for current loop, 850 µA/V for voltage loop) and a 2V buffered reference (VREF) with 0.5mA drive capability. Its dual analog control inputs (CTRL1 and CTRL2) set regulated current by selecting the lower of two voltage references, clamped to 0–1.5V, translating to 0–51mV across the external sense resistor.
It integrates independent high-side (HG) and low-side (LG) gate drivers with non-overlap timing (60–100ns), 5V VCC_INT regulator, and CBOOT floating supply generation. Overvoltage protection triggers at FB = 1.5V (25% above 1.21V nominal), holding shutdown for 13µs, while thermal shutdown activates at 163°C with 8°C 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 precise current sourcing/sinking for battery charging and LED driver applications where load matching is critical. |
| Voltage Regulation Accuracy | ±1.5% - ensures stable output voltage under varying load and line conditions, suitable for sensitive analog or digital loads. |
| Switching Frequency Range | 200kHz to 1MHz - adjustable via RT resistor or external SYNC signal, allowing optimization of size (higher fSW → smaller inductor/capacitors) vs. efficiency. |
| CTRL Pin Voltage Range | 0V to 1.5V - maps linearly to 0–51mV sense voltage, enabling accurate analog current programming with standard DACs or potentiometers. |
| Shutdown Quiescent Current | <1µA - minimizes standby power loss in always-on or energy-sensitive systems such as backup power modules. |
| Package | 20-Lead (4mm × 4mm) Plastic QFN with exposed thermal pad - provides low θJA (37°C/W) for high-power operation up to 125°C junction temperature. |
Pinout & Package
LT3741EUF#TRPBF uses a thermally enhanced 20-lead 4mm × 4mm plastic QFN package with exposed GND pad (Pin 21) that must be soldered to PCB for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN/UVLO (Pin 1) | Enable / Undervoltage Lockout Input | Active-high enable with 1.55V threshold and 130mV hysteresis; full shutdown below ~0.5V reduces IQ to <1µA. |
| VREF (Pin 2) | Buffered Reference Output | 2.0V ±1% reference capable of sourcing 0.5mA - used to bias CTRL1/CTRL2 divider networks with minimal error. |
| CTRL2 (Pin 3) | Thermal Control Input | Analog input (0–1.5V) that dynamically reduces regulated current during overtemperature events; overrides CTRL1 when lower. |
| GND (Pins 4,11,14,21) | Ground Return | Multiple ground connections and exposed pad ensure low-impedance return path for high-current switching and sensing. |
| CTRL1 (Pin 5) | Primary Current Set Input | Sets maximum regulated output current; clamped to 0–1.5V, directly controls 0–51mV sense voltage across RS. |
| SS (Pin 6) | Soft-Start Control | 11µA current source charges external capacitor to ramp regulated current gradually, preventing inrush into capacitive loads. |
| FB (Pin 7) | Voltage Feedback Input | 1.21V reference point for output voltage regulation; also senses overvoltage (trip at 1.5V) and initiates 13µs shutdown. |
| SENSE+ (Pin 8) | Current Sense Inverting Input | Connects to high-side of external sense resistor; forms differential pair with SENSE– to measure inductor current. |
| SENSE– (Pin 9) | Current Sense Non-Inverting Input | Reference current flows out to low-side of sense resistor; common-mode range extends to VIN – 2V. |
| VC (Pin 10) | Current Loop Compensation | Connects to compensation network (typically 20k–50kΩ + 2–5nF) to stabilize average current-mode control loop. |
| RT (Pin 12) | Frequency Setting Input | Resistor-to-ground sets switching frequency; 40kΩ yields ~1MHz, 200kΩ yields ~200kHz; current-limited to 60µA. |
| SYNC (Pin 13) | External Clock Input | Accepts external clock for synchronization; RT resistor must be set for 20% lower internal frequency to avoid jitter. |
| HG (Pin 15) | High-Side Gate Driver Output | Drives external N-channel MOSFET gate with 2.3Ω pull-up / 1.3Ω pull-down impedance; requires CBOOT bootstrap supply. |
| SW (Pin 16) | Switch Node | Connects high-side drain, low-side source, and inductor; carries full switching waveform and high di/dt currents. |
| CBOOT (Pin 17) | Bootstrap Supply | Floating 5V supply for HG driver; charged via Schottky diode from VCC_INT when SW is low. |
| LG (Pin 18) | Low-Side Gate Driver Output | Drives external N-channel MOSFET gate with 2.3Ω pull-up / 1.0Ω pull-down impedance; referenced to GND. |
| VCC_INT (Pin 19) | Internal 5V Regulator Output | Supplies power to logic, drivers, and CBOOT charging; regulated at 4.7–5.2V, current-limited to 50mA. |
| VIN (Pin 20) | Main Power Input | 6–36V input supply; requires local 4.7µF low-ESR ceramic bypass capacitor to minimize noise and ripple. |
Key Features
| Feature | Design Value |
|---|---|
| Dual analog current control (CTRL1/CTRL2) | Enables dynamic current limiting based on thermal feedback without microcontroller intervention - critical for self-protecting supercap chargers. |
| Source-and-sink current capability | Supports bidirectional current flow in applications like active load testing or regenerative braking interfaces, unlike LT3741-1. |
| Accurate 1.21V FB reference with OVP | Provides tight voltage regulation and fast overvoltage response (13µS shutdown) to protect downstream circuitry during fault conditions. |
| Programmable soft-start via SS pin | 11µA constant-current source allows precise control of current ramp rate using standard capacitor values - eliminates need for external timers. |
| Integrated 5V VCC_INT regulator | Eliminates need for external bias supply; powers internal logic, gate drivers, and CBOOT charging - simplifies BOM and layout. |
| Thermally enhanced QFN package | 4mm × 4mm footprint with exposed GND pad achieves 37°C/W θJA - sustains 20A operation at 125°C ambient with proper PCB copper area. |
Applications
| Supercapacitor Charging | Industrial Constant-Current Source |
|---|---|
|
Use Scenario: Rapid charging of 10–100F supercapacitor banks from 12V/24V industrial rails to 2.7V–5.5V per cell. IC Role / Device Role / Timing Role: Primary current-regulating controller managing bidirectional charge/discharge cycles with cycle-by-cycle overcurrent protection. Use Value: Enables full-rated 20A charging with ±6% current accuracy and automatic thermal derating via CTRL2 - avoids cell imbalance and extends lifetime. |
Use Scenario: Precision 0–20A current source for electroplating, material testing, or sensor calibration in factory-floor equipment. IC Role / Device Role / Timing Role: High-accuracy analog-controlled current regulator with independent voltage foldback to prevent damage during open-circuit faults. Use Value: Delivers stable current despite input voltage variation (6–36V) and load changes, with <1µA shutdown current for maintenance mode. |
| LED Driver for High-Power Arrays | Automotive Test Load Simulator |
|
Use Scenario: Driving multi-string high-brightness LED arrays (e.g., 10–20A @ 10–20V) in architectural or stage lighting systems. IC Role / Device Role / Timing Role: Constant-current buck controller with analog dimming interface (CTRL1) and thermal foldback (CTRL2) for safe thermal management. Use Value: Maintains consistent lumen output across temperature swings and input line variations, with built-in OVP protecting LEDs from overvoltage transients. |
Use Scenario: Simulating dynamic vehicle battery loads (e.g., starter motor, alternator dump) during ECU validation in lab environments. IC Role / Device Role / Timing Role: Programmable electronic load controller capable of sinking current during regenerative phases and sourcing during discharge tests. Use Value: Supports bidirectional operation (source/sink) with fast transient response (<100µs recovery) and programmable current limits - replaces multiple discrete test instruments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar constant-current, constant-voltage step-down controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3775 | Single-channel synchronous buck controller with ±1% current accuracy, no integrated VCC_INT regulator, requires external 5V bias. | Lacks dual CTRL pin thermal control and sink capability; optimized for higher efficiency at lower currents (<15A). | Select LTC3775 when tighter current accuracy is required and external bias supply is acceptable; not suitable for sink-only or thermally constrained designs. |
| LT3741EUF-1#TRPBF | Same pinout and package but disables current sinking; CTRL2 repurposed for voltage margining; identical current/voltage accuracy specs. | Designed for parallel controller configurations or unidirectional current applications where sink capability is unnecessary. | Choose LT3741EUF-1#TRPBF for cost-sensitive, high-volume parallel-phase designs where bidirectional operation is not needed. |
Compared with LTC3775 and LT3741EUF-1#TRPBF, the LT3741EUF#TRPBF uniquely combines source/sink capability, integrated thermal foldback via dedicated CTRL2, and self-contained 5V bias - making it optimal for supercapacitor charging and regenerative test loads where safety and autonomy are critical.
Availability
LT3741EUF#TRPBF is available at Aetrix Electronics and suitable for supercapacitor charging, industrial constant-current sources, and automotive test load simulation requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LT3741EUF#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 semiconductors, formed through the acquisition of Linear Technology in 2017.
The LT3741 product line was developed by Linear Technology specifically for high-accuracy, high-current DC/DC control in demanding industrial and energy-storage applications - emphasizing precision current regulation, thermal resilience, and robust fault protection.
FAQ
What is the maximum output current supported by the LT3741EUF#TRPBF?
The LT3741EUF#TRPBF is designed to regulate output current up to 20A with ±6% accuracy. This rating assumes proper thermal management using the exposed pad and adequate PCB copper area. Peak inductor current may exceed 20A depending on input/output voltage ratio and ripple design, but the average regulated current is capped at 20A by the CTRL1/CTRL2 interface and internal current loop.
Does the LT3741EUF#TRPBF support both sourcing and sinking current?
Yes, the LT3741EUF#TRPBF supports bidirectional current flow - it can both source and sink current. This capability distinguishes it from the LT3741-1 family and makes it suitable for applications like supercapacitor charge/discharge cycling and regenerative electronic loads. The LT3741EUF#TRPBF achieves this through its unique average current-mode architecture and symmetric gate drive design.
How does the CTRL2 pin function in the LT3741EUF#TRPBF?
In the LT3741EUF#TRPBF, the CTRL2 pin serves as a dedicated thermal control input. When an NTC thermistor network pulls CTRL2 below the voltage on CTRL1, the controller automatically reduces regulated output current to prevent overheating. This analog foldback occurs without microcontroller intervention and is fully integrated into the current regulation loop - a key differentiator from standard controllers requiring external monitoring circuits.
What is the purpose of the SS (Soft-Start) pin on the LT3741EUF#TRPBF?
The SS pin on the LT3741EUF#TRPBF controls startup behavior by ramping the regulated output current gradually. An external capacitor to ground is charged by a precise 11µA internal current source, allowing predictable current rise time. This prevents inrush into large capacitive loads (e.g., supercapacitor banks) and avoids triggering overcurrent protection during turn-on - eliminating the need for complex external sequencing circuits.
Can the LT3741EUF#TRPBF be synchronized to an external clock signal?
Yes, the LT3741EUF#TRPBF supports external clock synchronization via the SYNC pin. When used, the internal oscillator (set by the RT resistor) must be configured to run at least 20% slower than the external SYNC frequency to ensure reliable locking and minimize jitter. The SYNC pin must be grounded when not in use, and careful PCB layout is required to avoid noise coupling that could disrupt synchronization stability.
LT3741EUF#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 20-WFQFN 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-QFN (4x4)
LT3741EUF#TRPBF FAQ
1.How can I place an order for LT3741EUF#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3741EUF#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 LT3741EUF#TRPBF reliable?
The price and inventory of LT3741EUF#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3741EUF#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3741EUF#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3741EUF#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3741EUF#TRPBF?
LT3741EUF#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3741EUF#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 LT3741EUF#TRPBF?
For technical support, including LT3741EUF#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3741EUF#TRPBF requirements.
6.How does Aetrix verify that LT3741EUF#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3741EUF#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 LT3741EUF#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3741EUF#TRPBF?
All LT3741EUF#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3741EUF#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 LT3741EUF#TRPBF part is unused and in its original packaging.
Return procedure for LT3741EUF#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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