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Analog Devices Inc. LT3744IUHE#PBF
- Part No.:
- LT3744IUHE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 36-WFQFN Exposed Pad
- Datasheet:
-
LT3744IUHE#PBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 36QFN
- Quantity:
- Payment:
- Shipping:
Inventory:395
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Product details
Overview
LT3744IUHE#PBF from Analog Devices (formerly Linear Technology) is a fixed-frequency synchronous step-down LED driver controller designed for high-current RGB LED systems. It delivers up to 20A continuous or 40A pulsed LED current with ±3% regulation accuracy, programmable 100kHz–1MHz switching frequency, and supports inverting buck-boost topology to enable grounded heat sink operation in DLP projector and heads-up display applications.
For engineers reviewing the LT3744IUHE#PBF datasheet, LT3744IUHE#PBF pinout, LT3744IUHE#PBF application, or LT3744IUHE#PBF equivalent, key selection considerations include its triple analog control inputs (CTRL1/2/3), three independent PWM outputs (PWM_OUT1/2/3), floating VEE reference, and integrated open-drain fault reporting - all in a thermally enhanced 5mm × 6mm QFN-36 package.
Technical Context
The LT3744IUHE#PBF implements peak current mode control with DC-coupled LED current sensing via differential inputs LED_ISP/LED_ISN, enabling precise regulation across wide output voltage ranges (VEE to VIN). Its dual-loop architecture simultaneously manages LED current (via CTRLx/PWMx selection) and output voltage (via FB divider), with independent overvoltage and open/shorted LED protection.
It features three independent PWM dimming channels driving external NMOS FETs, synchronized gate drivers (TG/BG) with non-overlap timing (50ns), and a floating 5V INTVCC regulator referenced to VEE - allowing operation with VEE up to –20V relative to SGND for true inverting buck-boost configurations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 3.3V to 36V - supports single Li-ion battery input (3.3V) up to industrial 24V rails without level-shifting. |
| Max LED Current | 20A continuous / 40A pulsed - enables high-brightness multi-LED string drive with thermal derating via CTRLT pin. |
| Current Regulation Accuracy | ±3% over full range - ensures consistent luminance across temperature and line/load variations in projection systems. |
| Switching Frequency | 100kHz to 1MHz (RT-programmable) - balances efficiency (low fSW) and EMI/noise performance (high fSW) in compact layouts. |
| Dimming Ratio | 3000:1 PWM + 20:1 analog - supports flicker-free grayscale control in DLP and automotive HUD applications. |
| Package | 36-Lead 5mm × 6mm QFN with exposed VEE pad - provides low θJC = 3°C/W thermal path for high-power LED driver PCBs. |
| Operating Temp | –40°C to +125°C junction - qualified for automotive cabin and industrial embedded lighting environments. |
Pinout & Package
LT3744IUHE#PBF is housed in a thermally enhanced 36-lead plastic QFN (5mm × 6mm) with exposed VEE pad (Pin 37) requiring solder connection to PCB for thermal and electrical integrity. All signals are referenced either to SGND (inputs) or VEE (outputs, drivers, sense amps).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| EN/UVLO (1) | Enable & UVLO input | 1.30V rising threshold enables internal bias; 1.235V falling threshold initiates shutdown - ensures clean start-up under brownout. |
| CTRL1/2/3 (2,4,5) | Analog current setpoints | Selectable 0.075V–1.5V references for 3 independent LED current levels (20:1 dimming per channel). |
| PWM1/2/3 (7,8,9) | Digital channel select | Logic inputs that route CTRLx voltage to current loop and assert corresponding PWM_OUTx to drive external dimming FETs. |
| LED_ISP/LED_ISN (16,15) | LED current sense inputs | Differential pair referenced to VEE; regulates voltage drop across external sense resistor (e.g., 6mΩ) to set LED current. |
| FB (17) | Voltage regulation feedback | 1.205V reference input for output overvoltage protection and voltage-mode fallback during LED open-circuit events. |
| TG/BG (29,32) | High/low-side gate drivers | Integrated 3Ω/2.5Ω pull-up and 1.5Ω pull-down drivers with 50ns non-overlap - prevents shoot-through in external N-channel power stage. |
| FAULT (11) | Open-drain fault flag | Pulled low on FB <250mV (open LED) or FB >1.1V (overvoltage); 50Ω impedance enables direct microcontroller interrupt connection. |
| VEE (26,28,33,35,37) | Internal ground reference | Common reference for all drivers, sense amps, and outputs; may float up to –20V below SGND in inverting topologies. |
Key Features
| Feature | Design Value |
|---|---|
| Triple independent current control | Enables dynamic RGB color mixing or multi-zone brightness control using CTRL1/2/3 + PWM1/2/3 without external multiplexers. |
| Inverting buck-boost topology support | Allows VEE to float negative vs. SGND - permits grounded heatsink mounting for high-power RGB LEDs in space-constrained projectors. |
| Fault detection with dual thresholds | Simultaneous monitoring of FB (250mV/1.1V) and LED_ISP–LED_ISN (<6mV) enables robust open/short LED and overvoltage protection. |
| Thermal derating interface | CTRLT pin accepts NTC-derived voltage to linearly reduce regulated LED current as temperature rises - prevents thermal runaway in sealed enclosures. |
| Synchronized PWM dimming outputs | PWM_OUT1/2/3 drive external NMOS FETs with matched propagation delay (175ns high, 80ns low) - ensures precise timing alignment for flicker-free video frame sync. |
Applications
| RGB LED Projection Systems | Automotive Heads-Up Displays |
|---|---|
Use Scenario: Driving red/green/blue LED strings in DLP-based cinema or portable projectors requiring precise color balance and 5000:1 dimming. IC Role / Device Role / Timing Role: Primary LED current controller managing three independent current loops with synchronized PWM dimming for frame-accurate grayscale. Use Value: ±3% current regulation and 3000:1 PWM dimming ensure stable color point and zero visible flicker at 60Hz+ refresh rates. | Use Scenario: Illuminating combiner glass in vehicle HUDs with high ambient light rejection and thermal stability across –40°C to +85°C. IC Role / Device Role / Timing Role: High-efficiency LED driver operating in inverting buck-boost mode to maintain grounded heatsink while powered from 12V battery rail. Use Value: Floating VEE allows direct thermal coupling to chassis ground, reducing EMI and simplifying mechanical design in safety-critical automotive zones. |
| Industrial High-Power Lighting | Medical Endoscopic Illumination |
Use Scenario: Powering multi-die white LED arrays in surgical lighting or machine vision systems demanding stable lumen output and rapid dimming response. IC Role / Device Role / Timing Role: Synchronous step-down controller with analog + PWM dimming, overtemperature derating (via CTRLT), and fault reporting for system-level safety compliance. Use Value: 20A continuous capability and ±3% regulation accuracy eliminate luminance drift during extended operation in sterile environments. | Use Scenario: Driving miniature RGB LEDs inside endoscope tips where size, thermal management, and EMI are critical constraints. IC Role / Device Role / Timing Role: Compact LED driver enabling inverting topology to isolate LED cathodes from system ground - minimizing leakage currents in patient-connected devices. Use Value: 5mm × 6mm QFN package with VEE-referenced outputs meets IEC 60601 creepage/clearance requirements for Class II medical equipment. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-current LED controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3783EUHE#PBF | Single-channel controller; no integrated PWM_OUT drivers; requires external MOSFETs for dimming; supports up to 15A. | Lacks triple analog control and independent PWM outputs - suitable only for monochrome or externally multiplexed RGB systems. | Select when cost sensitivity outweighs need for integrated dimming FET control and multi-channel flexibility. |
| LM3409QMHX/NOPB | Single-channel asynchronous buck controller; max 5A; no VEE floating capability; no PWM_OUT pins; automotive AEC-Q100 qualified. | Designed for automotive headlamp LED drivers - lacks multi-channel control, inverting topology, and projector-grade dimming resolution. | Choose for AEC-Q100-compliant front-lighting where triple-channel operation and ultra-high dimming ratio are unnecessary. |
Compared with LTC3783EUHE#PBF and LM3409QMHX/NOPB, the LT3744IUHE#PBF uniquely integrates triple analog current control, three synchronized PWM outputs, and VEE-referenced drivers - making it the only solution capable of standalone RGB LED current regulation with flicker-free video synchronization in compact projector and HUD form factors.
Availability
LT3744IUHE#PBF is available at Aetrix Electronics and suitable for DLP projector development, automotive heads-up displays, and industrial high-power LED lighting requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LT3744IUHE#PBF 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 full product support, documentation, and manufacturing continuity for the LT3744 series.
The LT3744IUHE#PBF belongs to Linear's high-performance LED driver controller product line, engineered specifically for precision current regulation in multi-color, high-brightness projection and display systems requiring thermal resilience and layout flexibility.
FAQ
What is the maximum continuous LED current supported by the LT3744IUHE#PBF?
The LT3744IUHE#PBF supports up to 20A continuous LED current with ±3% regulation accuracy across temperature and line variations. Peak pulsed current capability reaches 40A, enabled by its robust gate drivers (TG/BG), low RDS(ON) outputs, and thermal derating via the CTRLT pin - making it suitable for high-lumen DLP projector and automotive HUD applications where transient brightness bursts are required.
How does the LT3744IUHE#PBF achieve flicker-free PWM dimming at 3000:1 ratio?
The LT3744IUHE#PBF achieves 3000:1 flicker-free PWM dimming through precisely matched propagation delays (175ns high / 80ns low) on its three PWM_OUT pins, combined with internal oscillator synchronization and jitter-free digital logic. This timing consistency ensures sub-microsecond edge alignment across all channels - critical for eliminating visible artifacts in video-frame-synchronized applications like DLP projection where multiple LEDs must switch in unison without temporal skew.
Can the LT3744IUHE#PBF operate in an inverting buck-boost configuration?
Yes, the LT3744IUHE#PBF supports inverting buck-boost topology by allowing VEE to float negative relative to SGND (up to –20V). This enables the LED string to be grounded while the IC operates from a single Li-ion battery - a key advantage for DLP projectors and HUDs requiring grounded heatsinks. The block diagram and pin functions explicitly define VEE as the internal reference for all drivers and sense amplifiers, decoupling them from SGND.
What protection features are integrated into the LT3744IUHE#PBF?
The LT3744IUHE#PBF integrates open LED (FB <250mV), shorted LED (FB >1.1V), overcurrent (ISP–ISN >110mV), and overtemperature (via CTRLT) protection. Fault conditions trigger the open-drain FAULT pin (50Ω pull-down) and disable BG - providing immediate system-level error signaling and safe shutdown. These protections are active across the full –40°C to +125°C operating range without external components.
Is the LT3744IUHE#PBF pin-compatible with other members of the LT3744 family?
Yes, the LT3744IUHE#PBF shares identical pinout, package (QFN-36), and electrical characteristics with LT3744EUHE#PBF and LT3744HUHE#PBF. The only difference is temperature grade: IUHE#PBF is rated for –40°C to +125°C, while EUHE#PBF is 0°C to +125°C and HUHE#PBF is –40°C to +150°C. All variants use the same PCB footprint and schematic design, enabling drop-in replacement based on thermal requirements.
LT3744IUHE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 36-WFQFN Exposed Pad
- Packaging:
- Tube
- 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)
LT3744IUHE#PBF FAQ
1.How can I place an order for LT3744IUHE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3744IUHE#PBF 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 LT3744IUHE#PBF reliable?
The price and inventory of LT3744IUHE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3744IUHE#PBF is usually 5 days.
3.What payment methods are accepted for LT3744IUHE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3744IUHE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3744IUHE#PBF?
LT3744IUHE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3744IUHE#PBF 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 LT3744IUHE#PBF?
For technical support, including LT3744IUHE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3744IUHE#PBF requirements.
6.How does Aetrix verify that LT3744IUHE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3744IUHE#PBF 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 LT3744IUHE#PBF meets industry standards.
7.What is the process for return or replacement of LT3744IUHE#PBF?
All LT3744IUHE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3744IUHE#PBF, 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 LT3744IUHE#PBF part is unused and in its original packaging.
Return procedure for LT3744IUHE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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