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Analog Devices Inc. LT3741IFE#TRPBF
- Part No.:
- LT3741IFE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- DC DC Switching Controllers
- Package:
- 20-TSSOP (0.173", 4.40mm Width) Exposed Pad
- Datasheet:
-
LT3741IFE#TRPBF.pdf
- Description:
- IC REG CTRLR BUCK 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,923
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Product details
Overview
LT3741IFE#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. It features average current-mode control, ±6% current regulation accuracy, ±1.5% voltage regulation accuracy, and supports input voltages from 6V to 36V with output voltage range up to (VIN – 2V). It is used in super-capacitor charging systems requiring accurate current limiting and robust short-circuit protection.
For engineers reviewing the LT3741IFE#TRPBF datasheet, LT3741IFE#TRPBF pinout, LT3741IFE#TRPBF application, or LT3741IFE#TRPBF equivalent, key selection considerations include its dual analog CTRL1/CTRL2 current programming interface, thermal current derating capability via CTRL2, 20-pin TSSOP package with exposed pad, and support for external frequency synchronization via SYNC pin.
Technical Context
The LT3741IFE#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-control architecture allows simultaneous regulation of output current (via CTRL1/CTRL2) and output voltage (via FB divider), with independent overcurrent detection (23mV offset above setpoint) and overvoltage lockout (1.5V FB threshold, 13µs shutdown).
It integrates high-side (HG) and low-side (LG) gate drivers with programmable non-overlap timing (60–100ns), internal 5V VCC_INT regulator (4.7–5.2V), and RT/SYNC-based frequency setting (200kHz–1MHz). The device supports bidirectional current sourcing/sinking and includes thermal shutdown 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 battery or bus supplies. |
| Output Current Accuracy | ±6% - ensures precise current regulation for LED drivers, battery charging, and super-capacitor pre-charge applications. |
| Voltage Regulation Accuracy | ±1.5% - maintains stable output voltage under load transients and line variations, critical for CV-CO systems. |
| Switching Frequency Range | 200kHz to 1MHz - adjustable via RT resistor or external SYNC clock, enabling EMI optimization and inductor size reduction. |
| CTRL1 Input Range | 0V to 1.5V - maps linearly to 0–51mV sense voltage across RS, enabling accurate analog current programming. |
| Shutdown Quiescent Current | <1µA - minimizes system standby power loss in always-on or energy-sensitive applications. |
| Thermal Shutdown Threshold | 163°C with 8°C hysteresis - protects against sustained overload while allowing recovery without manual reset. |
Pinout & Package
LT3741IFE#TRPBF uses a 20-lead plastic TSSOP package with exposed thermal pad (Pin 21 = GND), rated for –40°C to +125°C junction temperature and θJA = 38°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN/UVLO (Pin 4) | Enable / Undervoltage Lockout Input | Turns on 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 | Provides stable 2V reference (±1.5% over temp) for CTRL1/CTRL2 dividers; capable of sourcing 0.5mA. |
| CTRL2 (Pin 6) | Thermal Current Derating Input | Reduces regulated current when thermally constrained; lower of CTRL1/CTRL2 sets final current limit. |
| GND (Pins 2, 7, 16, 21) | Ground Return Path | Multiple ground pins and exposed pad ensure low-impedance return for power, signal, and thermal paths. |
| CTRL1 (Pin 8) | Primary Current Setpoint Input | Analog voltage (0–1.5V) sets high-level regulated current; internally clamped to prevent overrange operation. |
| SS (Pin 9) | Soft-Start Control | 11µA internal current charges external capacitor to ramp regulated current gradually during startup. |
| FB (Pin 10) | Voltage Feedback / Overvoltage Sense | 1.21V reference for CV regulation; triggers 13µs shutdown if voltage exceeds 1.5V (25% OV margin). |
| SENSE+ (Pin 11) | Current Sense Inverting Input | Connects to high-side of external sense resistor; common-mode range extends to VIN – 2V. |
| SENSE– (Pin 12) | Current Sense Non-Inverting Input | Sinks reference current from CTRL1/CTRL2; forms differential sense path with SENSE+ for average current loop. |
| VC (Pin 13) | Current Loop Compensation | Connects to RC network (e.g., 20kΩ + 2nF) to stabilize average current-mode control loop. |
| RT (Pin 14) | Frequency Setting Resistor | Resistor to GND sets switching frequency; 40kΩ yields ~1MHz; current-limited to 60µA. |
| SYNC (Pin 15) | External Clock Synchronization | Accepts external clock; RT must be set for 20% lower frequency to avoid jitter or instability. |
| HG (Pin 17) | High-Side Gate Driver Output | Drives external N-channel MOSFET gate; 2.3Ω pull-up / 1.3Ω pull-down impedance supports fast switching. |
| SW (Pin 18) | Switch Node | Connects high-side drain, low-side source, and inductor; high dv/dt node requiring careful layout. |
| CBOOT (Pin 19) | Floating High-Side Supply | Charged via Schottky diode from VCC_INT; provides 5V floating rail for HG driver bootstrap operation. |
| LG (Pin 20) | Low-Side Gate Driver Output | Drives external N-channel MOSFET gate; 2.3Ω pull-up / 1.0Ω pull-down impedance. |
| VCC_INT (Pin 1) | Internal 5V Regulator Output | Supplies CBOOT capacitor and internal circuitry; regulated 4.7–5.2V; current-limited to 50mA. |
| VIN (Pin 3) | Main Power Input | Accepts 6–36V input; requires local 4.7µF low-ESR bypass capacitor to GND for stability. |
Key Features
| Feature | Design Value |
|---|---|
| Dual analog current control (CTRL1 + CTRL2) | Enables dynamic current derating based on thermal feedback without changing hardware or firmware. |
| Average current-mode topology | Delivers stable, ripple-insensitive current regulation independent of output voltage-ideal for CC-CV sources. |
| Accurate overcurrent protection (23mV offset) | Provides cycle-by-cycle current limiting that activates immediately at setpoint-no soft-start delay. |
| Programmable frequency synchronization (SYNC) | Eliminates beat frequencies in multi-phase or noise-sensitive systems by aligning switching to external clock. |
| Integrated 5V VCC_INT regulator | Reduces external component count by powering internal logic and CBOOT charging circuitry from VIN. |
| Exposed thermal pad (TSSOP) | Improves thermal resistance by >30% vs standard TSSOP, supporting continuous 20A operation with proper PCB copper. |
Applications
| Super-Capacitor Charging | High-Power LED Driver |
|---|---|
Use Scenario: Pre-charging large super-capacitor banks (e.g., 50F, 24V) from 12–36V supply with controlled inrush current. IC Role / Device Role / Timing Role: Constant-current controller regulating charge current up to 20A, then transitioning to constant-voltage mode near full charge. Use Value: Prevents fuse blowing and MOSFET stress by enforcing precise current limit and seamless CC-to-CV transition. |
Use Scenario: Driving high-brightness LED strings (e.g., 10× 3W LEDs in series) requiring stable 1.5A–5A current over wide input voltage range. IC Role / Device Role / Timing Role: Primary current-regulating controller with analog dimming via CTRL1 voltage adjustment. Use Value: Maintains consistent lumen output despite input voltage variation or thermal drift, with ±6% current accuracy. |
| Industrial Battery Test Equipment | High-Reliability Power Supply Protection |
Use Scenario: Simulating battery discharge profiles during functional testing of portable devices, requiring programmable sink/source capability. IC Role / Device Role / Timing Role: Bidirectional current controller enabling both charging (source) and discharging (sink) modes via external FET configuration. Use Value: Enables single-board test fixtures to emulate real battery behavior without separate charge/discharge circuits. |
Use Scenario: Protecting sensitive downstream electronics (e.g., FPGA, ADC) from overvoltage/overcurrent events in 24V industrial power rails. IC Role / Device Role / Timing Role: Precision current limiter and fast OV protector with 13µs shutdown response and cycle-by-cycle current limiting. Use Value: Prevents catastrophic failure of downstream ICs during transient faults, exceeding standard TVS or fuse response times. |
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 |
|---|---|---|---|
| LTC3776EFE#TRPBF | Single-channel, no CTRL2 thermal derating input; 0.5% voltage accuracy (vs 1.5%); supports up to 15A peak. | Lacks dual-analog current control; better suited for precision CV-only or lower-current CC applications. | Select when higher voltage accuracy is required and thermal derating is handled externally or not needed. |
| LT8705EFE#TRPBF | Bidirectional buck-boost controller; wider VIN (2.8–80V); no integrated VREF; requires external current sense amplifier. | Supports reverse current flow and wider input range but adds complexity and cost for pure step-down CC-CV use. | Select only when bidirectional power flow or >36V input is mandatory; otherwise over-engineered for LT3741IFE#TRPBF use cases. |
Compared with LTC3776EFE#TRPBF and LT8705EFE#TRPBF, the LT3741IFE#TRPBF uniquely combines dual-analog current programming, integrated 2V reference, and optimized 20A CC-CV performance in a compact TSSOP package-making it the most direct solution for high-current super-capacitor charging and industrial LED drivers.
Availability
LT3741IFE#TRPBF is available at Aetrix Electronics and suitable for super-capacitor charging, high-power LED driving, and industrial battery test equipment requiring stable component supply and long-term production continuity.
Supply support for LT3741IFE#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), formed through acquisition of Linear Technology in 2017, is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LT3741IFE#TRPBF belongs to ADI's high-current DC/DC controller product line, engineered specifically for demanding constant-current applications such as energy storage charging, solid-state lighting, and precision power test instrumentation.
FAQ
What is the maximum regulated output current supported by the LT3741IFE#TRPBF?
The LT3741IFE#TRPBF supports up to 20A regulated output current when used with appropriate external MOSFETs, inductor, and sense resistor. This is achieved via the CTRL1 pin voltage (0–1.5V) mapping to 0–51mV across the sense resistor, with accuracy of ±6% over temperature. The actual achievable current depends on thermal design, PCB copper area, and component selection per the datasheet's inductor and FET guidelines.
Does the LT3741IFE#TRPBF support both constant-current and constant-voltage regulation simultaneously?
Yes, the LT3741IFE#TRPBF inherently supports simultaneous CC-CV operation. It regulates inductor current via average current-mode control until the output reaches the FB-set voltage; then the voltage loop reduces current to maintain regulation. The transition is automatic and seamless, with ±1.5% voltage accuracy and ±6% current accuracy-enabling true two-loop regulation in a single controller.
How does the CTRL2 pin function in the LT3741IFE#TRPBF?
The CTRL2 pin on the LT3741IFE#TRPBF provides thermal derating capability: the lower of the CTRL1 and CTRL2 analog voltages determines the final regulated current. When connected to an NTC thermistor divider, CTRL2 dynamically reduces current as temperature rises-preventing thermal runaway without external microcontroller intervention. This feature is unique to the LT3741 family and not present in the LT3741-1 variant.
Can the LT3741IFE#TRPBF be synchronized to an external clock?
Yes, the LT3741IFE#TRPBF supports external clock synchronization via the SYNC pin. To avoid jitter, the internal oscillator (set by RT) must run at least 20% slower than the external SYNC frequency. The SYNC pin must be grounded when unused, and layout best practices require shielding and separation from noisy traces to prevent injection-induced instability.
What is the purpose of the exposed pad on the LT3741IFE#TRPBF TSSOP package?
The exposed pad (Pin 21) on the LT3741IFE#TRPBF is electrically and thermally connected to GND. It must be soldered to a dedicated PCB thermal pad with multiple vias to internal ground planes. This reduces θJA from 38°C/W to ~25°C/W in typical layouts, enabling reliable 20A operation by dissipating heat from the internal gate drivers and regulators.
LT3741IFE#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
LT3741IFE#TRPBF FAQ
1.How can I place an order for LT3741IFE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3741IFE#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 LT3741IFE#TRPBF reliable?
The price and inventory of LT3741IFE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3741IFE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3741IFE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3741IFE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3741IFE#TRPBF?
LT3741IFE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3741IFE#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 LT3741IFE#TRPBF?
For technical support, including LT3741IFE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3741IFE#TRPBF requirements.
6.How does Aetrix verify that LT3741IFE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3741IFE#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 LT3741IFE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3741IFE#TRPBF?
All LT3741IFE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3741IFE#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 LT3741IFE#TRPBF part is unused and in its original packaging.
Return procedure for LT3741IFE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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