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Analog Devices Inc. LT3743EUFD#TRPBF
- Part No.:
- LT3743EUFD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 28-WFQFN Exposed Pad
- Datasheet:
-
LT3743EUFD#TRPBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 28QFN
- Quantity:
- Payment:
- Shipping:
Inventory:9,664
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Product details
Overview
LT3743EUFD#TRPBF from Analog Devices (formerly Linear Technology) is a fixed-frequency synchronous step-down DC/DC controller optimized for high-current LED driving with three-state current control. It delivers up to 20A regulated output current, supports 6V–36V input, achieves ±6% current regulation accuracy, and enables sub-2µs transitions between two current levels-used in DLP projectors for RGB color mixing via rapid PWM dimming.
For engineers reviewing the LT3743EUFD#TRPBF datasheet, LT3743EUFD#TRPBF pinout, LT3743EUFD#TRPBF application, or LT3743EUFD#TRPBF equivalent, key selection criteria include its dual-analog-control architecture (CTRL_L/CTRL_H), switched-capacitor topology for fast current settling, average current mode control loop stability, and integrated overvoltage/open-LED protection via FB pin.
Technical Context
The LT3743EUFD#TRPBF implements average current mode control using dual independent error amplifiers-one for low-current (VCL-compensated) and one for high-current (VCH-compensated) regulation states. Its internal 2V reference and 51mV typical sense voltage threshold enable precise inductor current regulation across 0V to (VIN – 2V) output range.
It features dedicated PWMGH/PWMGL gate drivers (3.2Ω pull-up / 1.75Ω pull-down) for external FETs controlling two output capacitors, enabling <2µs state transitions. Overcurrent protection is cycle-by-cycle, set by CTRL_H with +23mV offset relative to SENSE+–SENSE–, and shutdown draws <1µA.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6V to 36V - supports wide industrial and automotive supply rails without external pre-regulation. |
| Max Output Current | 20A - delivered via external high-side/low-side MOSFETs; requires proper thermal design on 4mm × 5mm QFN package. |
| Current Regulation Accuracy | ±6% - guaranteed over full temperature range, critical for consistent LED brightness and color fidelity. |
| Switching Frequency Range | 200kHz to 1MHz - set by RT resistor; allows optimization of efficiency vs. size for high-power LED loads. |
| Recovery Time Between States | <2µs - enables true-color PWM dimming up to 3000:1 ratio in RGB projection systems. |
| Shutdown Quiescent Current | <1µA - minimizes standby power loss in battery-backed or energy-sensitive lighting systems. |
| Overvoltage Protection Threshold | 1.3V on FB pin - triggers open-LED shutdown and discharges inductor current within 13µs. |
Pinout & Package
LT3743EUFD#TRPBF uses a thermally enhanced 28-lead (4mm × 5mm) plastic QFN package with exposed pad (Pin 29) soldered to PCB ground for thermal and electrical integrity. θJA = 37°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 1,5,9,20,21,29) | Power and signal ground reference | Multiple GND pins and exposed pad ensure low-impedance return path for high di/dt switching currents and stable current-sense reference. |
| CTRL_H / CTRL_L | Analog current setpoint inputs | 0–1.5V range sets high/low regulated LED current; clamped internally to prevent overrange errors. |
| CTRL_SEL | Current-level selection control | High/low logic selects between CTRL_H and CTRL_L references; enables fast state switching with 150ns interlock delay. |
| PWMGH / PWMGL | External capacitor-switching gate drivers | Drive external FETs to connect/disconnect dedicated output capacitors per current level-core to sub-2µs transition capability. |
| SENSE+ / SENSE– | Current-sense differential inputs | Measure voltage drop across external sense resistor (RS); 51mV typical threshold enables accurate 20A sensing with 2.5mΩ RS. |
| VCH / VCL | Compensation network connections | Independent compensation for high/low current loops ensures stability under both operating states. |
| FB | Voltage regulation and fault detection | 1.0V feedback reference; >1.3V triggers open-LED shutdown and capacitor discharge sequence. |
Key Features
| Feature | Design Value |
|---|---|
| Three-state current control | Enables RGB color mixing by rapidly toggling between two precisely regulated current levels (e.g., red/green/blue LEDs) with no intermediate state. |
| True Color PWM dimming | Delivers up to 3000:1 dimming ratio while preserving color point integrity-critical for DLP and laser projector applications. |
| Dual independent compensation | VCH/VCL pins allow separate loop tuning for each current level, maintaining stability during fast transitions and load transients. |
| Cycle-by-cycle overcurrent protection | Uses CTRL_H voltage plus 23mV offset to set trip point-prevents MOSFET failure without soft-start delay or latch behavior. |
| Integrated 5V VCC_INT regulator | Supplies internal circuitry and charges CBOOT capacitor; eliminates need for external bias rail in most designs. |
Applications
| DLP Projectors | High-Power Architectural Lighting |
|---|---|
Use Scenario: RGB LED illumination system requiring synchronized, flicker-free color switching at video frame rates. IC Role / Device Role / Timing Role: Primary current-mode controller managing dual-output capacitor switching and sub-2µs current state transitions. Use Value: Enables true-color PWM dimming (3000:1) without color shift-essential for high-fidelity image reproduction in commercial projectors. | Use Scenario: Outdoor LED floodlight with programmable intensity and thermal derating based on ambient temperature. IC Role / Device Role / Timing Role: High-efficiency, thermally robust LED driver supporting analog dimming (CTRL_T) and overvoltage protection for long-life operation. Use Value: ±6% current regulation ensures uniform lumen output across wide temperature and input voltage ranges, reducing binning requirements. |
| Laser Diode Drivers | Industrial Machine Vision Lighting |
Use Scenario: Pulsed laser diode array requiring precise current pulses with nanosecond-level timing control. IC Role / Device Role / Timing Role: Fast-settling current source with <2µs recovery time and cycle-by-cycle overcurrent limiting. Use Value: Prevents laser diode damage during transient faults while enabling high-speed modulation for structured light scanning. | Use Scenario: Stroboscopic LED illumination synchronized to camera exposure for high-speed inspection lines. IC Role / Device Role / Timing Role: PWM-triggered current controller with zero-latency start-up and deterministic turn-off via PWM pin. Use Value: Eliminates motion blur by delivering exact current pulses aligned to shutter timing-no residual tail current or overshoot. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-current LED driver controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3783EFE#TRPBF | Fixed-frequency current-mode controller with single current setpoint; no CTRL_SEL or dual-capacitor switching; max 10A output. | Lacks three-state control and sub-2µs transitions-suitable only for simpler constant-current LED strings. | Select when cost sensitivity outweighs need for RGB color mixing or ultra-fast dimming. |
| LM3423MH/NOPB | Constant-current buck controller with analog/PWM dimming; no dual-compensation or switched-capacitor topology; 5A max continuous. | Designed for mid-power LED arrays-not rated for 20A or projector-grade timing performance. | Choose for lower-current general lighting where thermal budget and BOM count are primary constraints. |
Compared with LTC3783EFE#TRPBF and LM3423MH/NOPB, the LT3743EUFD#TRPBF uniquely delivers 20A capability with hardware-enforced <2µs current-state transitions and independent VCH/VCL compensation-making it the only option for DLP projector RGB sequencing and laser diode pulsing at full scale.
Availability
LT3743EUFD#TRPBF is available at Aetrix Electronics and suitable for DLP projectors, high-power architectural lighting, laser diode drivers, and industrial machine vision lighting requiring stable component supply and long-term production continuity.
Supply support for LT3743EUFD#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 acquired Linear Technology in 2017 and maintains its legacy precision analog and power management product lines with full technical support and long-term manufacturing commitment.
The LT3743EUFD#TRPBF belongs to Linear's high-current LED driver controller family, designed specifically for applications demanding fast, accurate, and reliable current regulation in RGB projection, laser excitation, and high-intensity solid-state lighting.
FAQ
What is the maximum regulated LED current supported by the LT3743EUFD#TRPBF?
The LT3743EUFD#TRPBF supports up to 20A regulated LED current when used with appropriately rated external MOSFETs and thermal management. This is achieved through its average current mode control architecture and 51mV typical sense voltage threshold, allowing use of low-value sense resistors (e.g., 2.5mΩ) with minimal power loss. The LT3743EUFD#TRPBF datasheet specifies this maximum under recommended layout and cooling conditions.
How does the LT3743EUFD#TRPBF achieve sub-2µs current state transitions?
The LT3743EUFD#TRPBF achieves <2µs transitions using a switched-capacitor topology with two independent output capacitors controlled by PWMGH and PWMGL gate drivers. When CTRL_SEL toggles, the IC disables one capacitor path, inserts a 150ns interlock delay, then enables the other-while precharging the inductor to 70% of the target current. This architecture is explicitly confirmed in the LT3743EUFD#TRPBF block diagram and typical performance curves (Fig G29–G31).
What is the function of the CTRL_T pin on the LT3743EUFD#TRPBF?
The CTRL_T pin on the LT3743EUFD#TRPBF provides thermal derating input: applying a voltage to this pin reduces both CTRL_H and CTRL_L regulated current levels proportionally to prevent overheating. It is not a shutdown input but a linear scaling control-documented in the Pin Functions section and used in thermal management schemes for high-power LED arrays. The LT3743EUFD#TRPBF datasheet confirms its role in dynamic current reduction based on junction temperature.
Does the LT3743EUFD#TRPBF integrate overvoltage and open-LED protection?
Yes, the LT3743EUFD#TRPBF integrates both protections via the FB pin. When FB voltage exceeds 1.3V (30% above its 1.0V regulation threshold), it triggers open-LED shutdown: switching halts, and both output capacitors are connected to fully discharge inductor current within 13µs. This behavior is specified in the Electrical Characteristics table and verified in Typical Performance Characteristic G15–G16. The LT3743EUFD#TRPBF implements this as a hard fault response-not a warning flag.
What package type and thermal characteristics apply to the LT3743EUFD#TRPBF?
The LT3743EUFD#TRPBF uses a 28-lead 4mm × 5mm plastic QFN package (UFD) with exposed thermal pad (Pin 29) that must be soldered to PCB ground. Its thermal resistance is θJA = 37°C/W, and absolute maximum junction temperature is 125°C. These specifications are defined in the Order Information and Absolute Maximum Ratings sections of the LT3743EUFD#TRPBF datasheet and confirmed by Linear's package drawings.
LT3743EUFD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 28-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Controller
- Topology:
- Step-Down (Buck)
- Internal Switch(s):
- No
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 6V
- Voltage - Supply (Max):
- 36V
- Voltage - Output:
- -
- Current - Output / Channel:
- -
- Frequency:
- 200kHz ~ 1MHz
- Dimming:
- PWM
- Applications:
- Lighting
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-QFN (4x5)
LT3743EUFD#TRPBF FAQ
1.How can I place an order for LT3743EUFD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3743EUFD#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 LT3743EUFD#TRPBF reliable?
The price and inventory of LT3743EUFD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3743EUFD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3743EUFD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3743EUFD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3743EUFD#TRPBF?
LT3743EUFD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3743EUFD#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 LT3743EUFD#TRPBF?
For technical support, including LT3743EUFD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3743EUFD#TRPBF requirements.
6.How does Aetrix verify that LT3743EUFD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3743EUFD#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 LT3743EUFD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3743EUFD#TRPBF?
All LT3743EUFD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3743EUFD#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 LT3743EUFD#TRPBF part is unused and in its original packaging.
Return procedure for LT3743EUFD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3743EUFD#TRPBF Tags
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BCR402RE6327HTSA1
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BCR430UXTSA2
Infineon Technologies
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BCR420UE6433HTMA1
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BCR420UE6327HTSA1
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BCR421UE6327HTSA1
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LYT1604D-TL
Power Integrations
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HV9910CLG-G
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CL2N8-G
Microchip Technology
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BCR420UW6-7
Diodes Incorporated
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BCR421UW6-7
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BCR420UFD-7
Diodes Incorporated
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BCR421UFD-7
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