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Analog Devices Inc. LT3756IUD#TRPBF
- Part No.:
- LT3756IUD#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 16-WFQFN Exposed Pad
- Datasheet:
-
LT3756IUD#TRPBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 16QFN
- Quantity:
- Payment:
- Shipping:
Inventory:1,240
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Product details
Overview
LT3756IUD#TRPBF from Analog Devices is a high-voltage constant-current LED controller IC designed for automotive and industrial LED drivers. It operates as a current-mode DC/DC controller driving external N-channel MOSFETs, supports 6V–100V input, delivers up to 100V output, enables 3000:1 PWM dimming, and features high-side current sensing for boost/buck/buck-boost topologies.
For engineers reviewing the LT3756IUD#TRPBF datasheet, LT3756IUD#TRPBF pinout, LT3756IUD#TRPBF application, or LT3756IUD#TRPBF equivalent, key selection considerations include its 100mV high-side current sense threshold, 100kHz–1MHz adjustable switching frequency, AEC-Q100 qualification, thermally enhanced 3mm × 3mm QFN package, and dual regulation (constant-current + constant-voltage) capability.
Technical Context
The LT3756IUD#TRPBF implements fixed-frequency current-mode control with internal 7.15V INTVCC regulator, ground-referenced FB pin for voltage loop regulation and open-LED protection, and programmable CTRL pin for analog dimming. Its high-side ISP/ISN current sense architecture enables flexible topology selection without requiring floating sense amplifiers.
It integrates PWM disconnect switch driver, programmable soft-start, undervoltage lockout with hysteresis, and thermal shutdown. The device supports true-color PWM dimming via dedicated PWM input and analog dimming via CTRL pin, with open-LED fault reporting on OPENLED pin (active-low open-drain).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6V to 100V - supports wide-range automotive battery systems including cold-crank and load-dump transients. |
| Output Voltage Capability | Up to 100V - enables driving long LED strings in headlamps, signage, and industrial lighting. |
| Current Sense Threshold | 100mV (typical) at ISP–ISN - enables precise, low-loss high-side LED current sensing with minimal power dissipation. |
| Switching Frequency Range | 100kHz to 1MHz - allows optimization of magnetic size, efficiency, and EMI performance via RT resistor. |
| Dimming Ratio | 3000:1 PWM - ensures flicker-free, high-fidelity color consistency in display and automotive lighting applications. |
| Package & Thermal Rating | 16-lead 3mm × 3mm QFN, –40°C to +125°C - thermally enhanced for high-power density designs with exposed GND pad soldering. |
| AEC-Q100 Grade | Grade I - qualified for automotive under-hood and exterior lighting applications per AEC-Q100 Rev H. |
Pinout & Package
LT3756IUD#TRPBF is housed in a 16-lead (3mm × 3mm) plastic QFN package with exposed thermal pad (Pin 17 = GND). The package provides low θJA = 68°C/W and requires PCB-level thermal management via soldered exposed pad.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PWMOUT (Pin 1) | Buffered PWM output / Overvoltage fault signal | Drives NMOS disconnect switch; pulled low when FB exceeds VFB + 60mV to protect LEDs from overvoltage events. |
| FB (Pin 2) | Voltage feedback / Open-LED detection input | Regulates to 1.25V nominal; asserts OPENLED when FB falls below VFB – 50mV, indicating open-string condition. |
| ISN (Pin 3) | Negative current sense input | High-side current sense return; bias current <25µA; enables short-circuit detection when ISN < 3V. |
| ISP (Pin 4) | Positive current sense input | High-side current sense high side; common-mode range up to 100V; bias current varies with CTRL voltage. |
| VC (Pin 5) | Error amplifier output | Transconductance amplifier output; used for loop compensation; high-impedance during PWM low for state retention. |
| CTRL (Pin 6) | Analog dimming / Current threshold control | Programs ISP–ISN threshold from 0V to 100mV linearly (0–1V), then holds full-scale above 1.2V. |
| VREF (Pin 7) | 2.0V reference output | Stable 2.0V reference (±2%) sourcing up to 100µA; used to bias CTRL or temperature-compensate LED current. |
| PWM (Pin 8) | Digital dimming enable | Active-high; disables switching and idles oscillator when low; internal pull-down; drives PWMOUT synchronously. |
| OPENLED (Pin 9) | Open-LED status indicator | Open-drain output asserted low when FB < VFB – 50mV; requires external pull-up <1mA; latched during PWM low. |
| SS (Pin 10) | Soft-start timing | 10µA internal pull-up to 2.5V rail; external capacitor sets startup ramp time; reset by UVLO or thermal fault. |
| RT (Pin 11) | Frequency programming | Resistor-to-GND sets oscillator frequency (100kΩ → ~100kHz, 10kΩ → ~1MHz); no internal pull-up/down. |
| SHDN/UVLO (Pin 12) | Shutdown & input undervoltage detection | 1.22V falling threshold with user-programmable hysteresis via resistor divider; sub-µA quiescent current in shutdown. |
| INTVCC (Pin 13) | Internal regulated supply | 7.15V LDO output powering gate driver and logic; requires 4.7µF local ceramic bypass; UVLO trips at 4.1V. |
| VIN (Pin 14) | Main power input | Accepts 6V–100V; must be bypassed with ≥0.22µF ceramic cap near pin; powers INTVCC and internal circuitry. |
| SENSE (Pin 15) | Low-side switch current sense | Kelvin-connected to source of external N-MOSFET; monitors peak switch current for current-mode control. |
| GATE (Pin 16) | N-MOSFET gate driver | Drives external FET gate between INTVCC and GND; clamped low during shutdown/fault/idle states. |
| GND (Pin 17) | Power & signal ground | Exposed thermal pad; serves as current sense return for SENSE and ISN; must be soldered to PCB ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| High-side current sensing | Enables topology flexibility (boost/buck/buck-boost/SEPIC/flyback) without isolated sense amplifiers or floating supplies. |
| True Color PWM™ dimming | 3000:1 ratio preserves LED chromaticity across dimming range-critical for automotive headlamps and displays. |
| Integrated open-LED protection | FB-based detection with OPENLED pin assertion avoids catastrophic overvoltage failure in string-open conditions. |
| Programmable switching frequency | 100kHz–1MHz range via single RT resistor allows trade-off between magnetics size, efficiency, and EMI compliance. |
| AEC-Q100 Grade I qualification | Validated for automotive use across –40°C to +125°C junction temperature with robust transient immunity and reliability testing. |
Applications
| Automotive Headlamp Driver | Industrial High-Bay Lighting |
|---|---|
Use Scenario: Driving 30W white LED arrays in vehicle forward lighting with dynamic beam shaping and adaptive driving beam (ADB) control. IC Role / Device Role / Timing Role: Constant-current controller regulating LED string current while supporting rapid PWM dimming for pixel-level intensity control. Use Value: 94% efficiency at 30W enables compact thermal design; 3000:1 dimming preserves color fidelity during low-beam transitions. | Use Scenario: Powering multi-string 100V LED fixtures in warehouse and factory environments with 0–10V or DALI-compatible analog dimming. IC Role / Device Role / Timing Role: High-voltage constant-current source enabling single-stage conversion from 48V DC bus to 100V LED string. Use Value: 100V output capability eliminates need for cascaded converters; AEC-Q100 qualification ensures long-term reliability in harsh industrial settings. |
| UV-C Disinfection Module | Battery-Powered Emergency Light |
Use Scenario: Driving high-current UVC LEDs (265nm) requiring precise current regulation and thermal derating due to efficiency losses. IC Role / Device Role / Timing Role: Constant-current controller with analog dimming (CTRL) for thermal foldback and PWM for on/off pulsing protocols. Use Value: 100mV ISP–ISN threshold minimizes sense resistor power loss; high-side sensing avoids ground loop interference in sensitive optical systems. | Use Scenario: LED emergency lighting powered from 12V–48V lead-acid or LiFePO₄ batteries with extended runtime and low-quiescent operation. IC Role / Device Role / Timing Role: Wide-input buck-boost LED driver maintaining constant brightness across battery discharge curve. Use Value: <1µA shutdown current extends battery life; 6V minimum VIN supports deep-discharge recovery; programmable UVLO prevents battery over-discharge. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3756IMSE#TRPBF | Same functionality and specs, but in 16-lead MSOP package (4mm × 3mm); higher θJA = 43°C/W; no exposed thermal pad. | Preferred where board space permits larger footprint and thermal requirements are less stringent. | Select when MSOP layout compatibility exists or thermal margin >15°C is available at full load. |
| LT3762EFE#TRPBF | Higher 150V input rating; integrated 1.5A gate driver; no OPENLED pin; different CTRL dimming behavior (logarithmic vs linear). | Suitable for ultra-high-voltage industrial LED drivers (>100V input) but lacks open-LED status reporting. | Choose only if input exceeds 100V or integrated gate driver simplifies layout; not drop-in compatible. |
Compared with LT3756IMSE#TRPBF, the LT3756IUD#TRPBF offers superior thermal performance in compact form factor, while LT3762EFE#TRPBF trades open-LED diagnostics for higher input voltage tolerance and integrated drive strength-making LT3756IUD#TRPBF optimal for space-constrained automotive lighting where fault visibility is critical.
Availability
LT3756IUD#TRPBF is available at Aetrix Electronics and suitable for automotive headlamp systems, industrial high-bay lighting, UV-C disinfection modules, and battery-powered emergency lighting requiring stable component supply and AEC-Q100-compliant performance.
Supply support for LT3756IUD#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision, industrial, automotive, and communications markets.
The LT3756 product line was engineered specifically for high-reliability, high-voltage LED current regulation in demanding environments-including automotive exterior lighting and industrial solid-state illumination-with emphasis on fault resilience, thermal robustness, and topology flexibility.
FAQ
What is the maximum input voltage supported by the LT3756IUD#TRPBF?
The LT3756IUD#TRPBF supports an absolute maximum input voltage of 100V, with guaranteed operation from 6V to 100V. This makes it suitable for automotive applications experiencing load-dump transients up to 100V, as well as industrial 48V and 96V DC systems. The device includes internal protection against overvoltage stress on all pins, including SHDN/UVLO and ISP/ISN.
Does the LT3756IUD#TRPBF support both constant-current and constant-voltage regulation?
Yes, the LT3756IUD#TRPBF supports dual regulation modes. Constant-current regulation is achieved via high-side ISP/ISN sensing and CTRL pin programming, while constant-voltage regulation uses the FB pin referenced to 1.25V. Both loops operate simultaneously, with priority given to current regulation unless the LED string opens-then FB takes over to prevent overvoltage.
How does the OPENLED pin function on the LT3756IUD#TRPBF?
The OPENLED pin on the LT3756IUD#TRPBF is an open-drain output that pulls low when the FB voltage drops below VFB – 50mV (typically 1.20V), signaling an open LED string. It remains latched during PWM low periods and updates when PWM goes high. An external pull-up resistor (<1mA) is required, and the pin is active only on LT3756 and LT3756-2 variants-not LT3756-1.
What package type and thermal characteristics does the LT3756IUD#TRPBF use?
The LT3756IUD#TRPBF uses a 16-lead 3mm × 3mm plastic QFN package with exposed thermal pad (Pin 17 = GND). Its thermal resistance is θJA = 68°C/W and θJC = 4.2°C/W. Successful thermal design requires soldering the exposed pad to a large PCB copper area, as thermal performance degrades significantly without proper pad connection.
Can the LT3756IUD#TRPBF be synchronized to an external clock?
No, the LT3756IUD#TRPBF does not support external synchronization. That feature is exclusive to the LT3756-1 variant (e.g., LT3756IUD-1#TRPBF), which replaces the OPENLED pin with SYNC functionality. The LT3756IUD#TRPBF is the base version (non–1, non–2), so it retains OPENLED but lacks SYNC capability-confirming its part number suffix contains no "-1" or "-2".
LT3756IUD#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-WFQFN Exposed Pad
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- DC DC Controller
- Topology:
- Flyback, SEPIC, Step-Down (Buck), Step-Up (Boost)
- Internal Switch(s):
- No
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 6V
- Voltage - Supply (Max):
- 100V
- Voltage - Output:
- 100V
- Current - Output / Channel:
- -
- Frequency:
- 100kHz ~ 1MHz
- Dimming:
- Analog, PWM
- Applications:
- -
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-QFN (3x3)
LT3756IUD#TRPBF FAQ
1.How can I place an order for LT3756IUD#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3756IUD#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 LT3756IUD#TRPBF reliable?
The price and inventory of LT3756IUD#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3756IUD#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3756IUD#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3756IUD#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3756IUD#TRPBF?
LT3756IUD#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3756IUD#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 LT3756IUD#TRPBF?
For technical support, including LT3756IUD#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3756IUD#TRPBF requirements.
6.How does Aetrix verify that LT3756IUD#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3756IUD#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 LT3756IUD#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3756IUD#TRPBF?
All LT3756IUD#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3756IUD#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 LT3756IUD#TRPBF part is unused and in its original packaging.
Return procedure for LT3756IUD#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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