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Analog Devices Inc. LT3744EUHE#TRPBF
- Part No.:
- LT3744EUHE#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 36-WFQFN Exposed Pad
- Datasheet:
-
LT3744EUHE#TRPBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 36QFN
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
LT3744EUHE#TRPBF from Analog Devices (formerly Linear Technology) is a high-current synchronous step-down LED driver controller designed to regulate up to 20A continuous or 40A pulsed LED current with ±3% accuracy. It supports 3.3V–36V input, programmable 100kHz–1MHz switching frequency via RT pin, and features three independent PWM/CTRL channels for multi-current RGB or time-multiplexed LED control in DLP projectors and heads-up displays.
For engineers reviewing the LT3744EUHE#TRPBF datasheet, LT3744EUHE#TRPBF pinout, LT3744EUHE#TRPBF application, or LT3744EUHE#TRPBF equivalent, key selection considerations include its unique inverting buck-boost topology enabling grounded heatsink operation, floating VEE reference architecture, integrated open-drain fault flag, and thermally deratable current regulation via CTRLT pin.
Technical Context
The LT3744EUHE#TRPBF implements fixed-frequency peak current mode control with dual-loop regulation: LED current is set by analog voltage at CTRL1–CTRL3 pins (0–1.5V → 3–60mV sense voltage), while output voltage is regulated via FB pin with 1.205V threshold and ±3% accuracy. Its floating VEE domain isolates gate drivers (TG/BG), PWM outputs, and current sense inputs (LED_ISP/LED_ISN, ISP/ISN) from SGND-enabling negative-output configurations without level shifters.
Three independent PWM inputs select among three analog current references and activate corresponding PWM_OUTx drivers for external NMOS FETs. The device integrates dedicated gm amplifiers for LED current sensing (200μA/V) and inductor current sensing (100μA/V), plus C/10 comparator for precise overcurrent detection with 4–8mV falling threshold and 3mV hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.3V to 36V - supports single Li-ion battery (3.3V) up to industrial 24V rails without external pre-regulation. |
| Max Continuous LED Current | 20A - achieved using external high-side and low-side MOSFETs with accurate DC current sensing at LED_ISP/LED_ISN. |
| Current Regulation Accuracy | ±3% over temperature - ensures stable luminance in high-power projection systems across –40°C to 125°C junction range. |
| Switching Frequency Range | 100kHz to 1MHz - set by RT resistor; enables optimization of efficiency vs. size for 0.47µH–2.2µH inductors. |
| LED Dimming Ratio | 3000:1 PWM + 20:1 analog - supports flicker-free grayscale control in DLP and automotive HUD applications. |
| Package Thermal Resistance | θJA = 34°C/W, θJC = 3°C/W - 5mm × 6mm QFN-36 with exposed VEE pad enables >15W power dissipation with proper PCB copper. |
| Fault Protection | Open/shorted LED detection, OVLO, thermal shutdown, and active-low FAULT pin - provides system-level safety without external monitoring circuitry. |
Pinout & Package
LT3744EUHE#TRPBF is housed in a thermally enhanced 36-lead (5mm × 6mm) plastic QFN package with exposed VEE pad (Pin 37) requiring solder connection to PCB for thermal and electrical integrity. All signals are referenced either to SGND (digital/analog inputs) or VEE (gate drivers, PWM outputs, current sense inputs).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN/UVLO (1) | Enable & undervoltage lockout input | 1.30V rising threshold; pulls down 4.8µA below 1.235V - enables precise power sequencing and brownout protection. |
| CTRL1–CTRL3 (2,4,5) | Analog current reference inputs | 0–1.5V sets 3–60mV LED sense voltage; 20:1 dimming range - allows independent current programming for RGB LEDs. |
| PWM1–PWM3 (7–9) | Digital channel select inputs | High-active logic selects corresponding CTRLx and asserts PWM_OUTx - enables time-multiplexed multi-current drive without MCU intervention. |
| LED_ISP/LED_ISN (16,15) | LED current sense differential inputs | Referenced to VEE; regulate voltage drop across external sense resistor - supports cathode-side sensing with grounded heatsink. |
| TG/BG (29,32) | High-side/low-side gate drivers | 3Ω/2.5Ω pull-up, 1.5Ω pull-down RON - drives external N-channel MOSFETs with <50ns non-overlap to prevent shoot-through. |
| PWM_OUT1–PWM_OUT3 (27,25,23) | External dimming FET drivers | Capable of sinking 5Ω / sourcing 1.65Ω at VFNEG = –15V - directly controls series NMOS switches for PWM dimming. |
| VEE (26,28,33,35,37) | Internal ground reference | Exposed pad must be soldered; supports up to –20V offset vs SGND - enables inverting buck-boost topology with single Li-ion supply. |
Key Features
| Feature | Design Value |
|---|---|
| Inverting buck-boost topology support | VEE floating reference allows negative output voltage generation - eliminates need for isolated supplies when driving multicolor LED strings from 3.3V–12V sources. |
| Triple independent current regulation channels | CTRL1/PWM1, CTRL2/PWM2, CTRL3/PWM3 enable simultaneous or time-multiplexed control of three distinct LED currents - ideal for RGB color mixing in DLP projectors. |
| Thermal derating via CTRLT pin | Voltage at CTRLT (Pin 6) caps regulated current when lower than active CTRLx - enables simple NTC-based thermal foldback without microcontroller. |
| Integrated fault reporting | Open-drain FAULT pin asserts low for FB <250mV (open LED) or FB >1.1V (shorted LED) - simplifies system-level diagnostics and safety interlocks. |
| Programmable soft-start | 5µA constant-current charge into SS-to-VEE capacitor - prevents inrush current and stabilizes startup in high-current LED applications. |
Applications
| DLP Projector Light Engine | Automotive Heads-Up Display (HUD) |
|---|---|
Use Scenario: Driving red/green/blue LED arrays with rapid current switching for sequential color projection. IC Role / Device Role / Timing Role: Synchronous step-down controller with triple analog current references and PWM channel selection. Use Value: Enables 5000:1 flicker-free dimming and precise color point stability via ±3% current regulation across temperature. |
Use Scenario: Powering high-brightness monochrome LED source behind combiner glass with strict thermal constraints. IC Role / Device Role / Timing Role: Inverting buck-boost LED driver with thermally derated current control via CTRLT. Use Value: Grounded heatsink compatibility reduces EMI and improves thermal management in space-constrained dashboard environments. |
| High-Power Stage Lighting | Medical Endoscopic Illumination |
Use Scenario: Regulating 20A+ white LED strings for theatrical spotlights requiring smooth analog + PWM dimming. IC Role / Device Role / Timing Role: High-current DC/DC controller with 3000:1 combined dimming ratio and open/short LED protection. Use Value: Eliminates visible stepping during dimming transitions and ensures fail-safe shutdown on LED string failure. |
Use Scenario: Driving sterilizable LED modules in endoscopes where reliability, compact size, and low noise are critical. IC Role / Device Role / Timing Role: Compact QFN-based LED driver with integrated voltage regulation and fault flag reporting. Use Value: Reduces BOM count by integrating FB-based overvoltage protection and eliminating external supervisor ICs. |
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#PBF | Single-channel, no VEE floating capability; max 10A LED current; no integrated PWM_OUT drivers | Lacks triple-channel current control and inverting topology - suitable only for simpler single-color, non-floating applications | Select when cost-sensitive designs require basic constant-current regulation without RGB multiplexing or negative output capability |
| LM3409QMHX/NOPB | Single-channel buck LED controller; 1.25V FB reference; no analog dimming inputs; max 5A typical | No CTRLx/PWMx interface; limited to basic PWM dimming; not rated for >125°C operation | Choose for entry-level automotive lighting where thermal derating and multi-current precision are not required |
Compared with LTC3783EFE#PBF and LM3409QMHX/NOPB, the LT3744EUHE#TRPBF uniquely delivers triple independent current regulation, VEE-referenced floating architecture for grounded heatsinks, and integrated PWM_OUT drivers-making it the only option capable of full-featured DLP projector light engine implementation.
Availability
LT3744EUHE#TRPBF is available at Aetrix Electronics and suitable for DLP projector light engines, automotive heads-up displays, and high-power stage lighting requiring stable component supply, extended temperature operation (–40°C to 125°C), and long-term production continuity.
Supply support for LT3744EUHE#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 high-performance analog IC portfolio, including precision power management solutions for demanding industrial and automotive applications.
The LT3744EUHE#TRPBF belongs to Linear's high-current LED driver controller product line, engineered specifically for multi-channel, high-fidelity illumination systems requiring flicker-free dimming, thermal robustness, and flexible topology support beyond standard buck conversion.
FAQ
What is the maximum continuous LED current supported by the LT3744EUHE#TRPBF?
The LT3744EUHE#TRPBF supports up to 20A continuous LED current when used with appropriately rated external MOSFETs, inductors, and PCB layout. Its ±3% current regulation accuracy and thermal derating via CTRLT pin ensure stable operation under sustained load conditions. Peak pulsed current capability reaches 40A for short-duration strobe applications.
How does the LT3744EUHE#TRPBF achieve grounded heatsink operation for RGB LEDs?
The LT3744EUHE#TRPBF achieves grounded heatsink operation through its unique inverting buck-boost topology and floating VEE reference. By allowing VEE to sit at a negative potential relative to SGND, the LED cathodes can be tied to system ground while the anodes are driven from the switch node-enabling direct thermal coupling of high-power RGB LEDs to a common heatsink without isolation components.
Can the LT3744EUHE#TRPBF drive multiple LED strings with different current levels simultaneously?
Yes-the LT3744EUHE#TRPBF supports time-multiplexed multi-string operation using its three independent CTRL/PWM channels. When PWM1 is high, CTRL1 sets current for String 1 and PWM_OUT1 activates its series FET; similarly for PWM2/CTRL2 and PWM3/CTRL3. This enables precise, independent current control for RGB or multi-zone lighting without additional controllers.
What is the role of the CTRLT pin on the LT3744EUHE#TRPBF?
The CTRLT pin on the LT3744EUHE#TRPBF provides thermally adaptive current limiting: when the voltage at CTRLT falls below the active CTRLx voltage, it caps the regulated LED current proportionally. This allows simple integration of an NTC thermistor to reduce LED current as temperature rises-preventing thermal runaway in enclosed or high-ambient environments.
Does the LT3744EUHE#TRPBF include overvoltage and open-circuit LED protection?
Yes-the LT3744EUHE#TRPBF includes comprehensive fault protection. An overvoltage condition (FB >1.1V) or open LED (FB <250mV with LED_ISP–LED_ISN <6mV) pulls the open-drain FAULT pin low. Additionally, the device monitors inductor current via ISP/ISN and triggers shutdown if the 110mV OC threshold is exceeded-ensuring safe operation under all fault conditions.
LT3744EUHE#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 36-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:
- 3
- Voltage - Supply (Min):
- 3.3V
- Voltage - Supply (Max):
- 36V
- Voltage - Output:
- -
- Current - Output / Channel:
- -
- Frequency:
- 1MHz
- Dimming:
- Analog, PWM
- Applications:
- -
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 36-QFN (5x6)
LT3744EUHE#TRPBF FAQ
1.How can I place an order for LT3744EUHE#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3744EUHE#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 LT3744EUHE#TRPBF reliable?
The price and inventory of LT3744EUHE#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3744EUHE#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3744EUHE#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3744EUHE#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3744EUHE#TRPBF?
LT3744EUHE#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3744EUHE#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 LT3744EUHE#TRPBF?
For technical support, including LT3744EUHE#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3744EUHE#TRPBF requirements.
6.How does Aetrix verify that LT3744EUHE#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3744EUHE#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 LT3744EUHE#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3744EUHE#TRPBF?
All LT3744EUHE#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3744EUHE#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 LT3744EUHE#TRPBF part is unused and in its original packaging.
Return procedure for LT3744EUHE#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3744EUHE#TRPBF Tags
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