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Analog Devices Inc. LT3756EMSE-2#PBF
- Part No.:
- LT3756EMSE-2#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3756EMSE-2#PBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,599
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Product details
Overview
LT3756EMSE-2#PBF from Analog Devices is a high-voltage constant-current LED controller IC designed for automotive and industrial LED drivers. It supports 6V–100V input, delivers up to 100V output, senses current on the high side (100mV threshold), operates in boost/buck/buck-boost/SEPIC/flyback topologies, and features true-color PWM dimming up to 3000:1 - used in 30W white LED headlamp drivers.
For engineers reviewing the LT3756EMSE-2#PBF datasheet, LT3756EMSE-2#PBF pinout, LT3756EMSE-2#PBF application, or LT3756EMSE-2#PBF equivalent, key selection considerations include high-side current sensing architecture, open-LED fault detection via OPENLED pin, programmable switching frequency (100kHz–1MHz), AEC-Q100 qualification, and dual regulation (constant-current + constant-voltage) capability.
Technical Context
The LT3756EMSE-2#PBF implements fixed-frequency current-mode control with internal 7.15V INTVCC regulator driving an N-channel MOSFET gate. Its high-side ISP/ISN current sense inputs enable topology flexibility and eliminate ground loop issues in LED string configurations.
It integrates dual-loop regulation: LED current is controlled by the difference between ISP and ISN referenced to CTRL pin voltage (100mV full-scale), while FB pin enables constant-voltage operation at 1.25V nominal. The LT3756-2 variant adds improved open-LED status reporting with latched fault behavior during PWM idle periods.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6V to 100V - supports wide-range DC supplies including 12V/24V/48V systems with 100V transient tolerance. |
| Output Voltage Capability | Up to 100V - enables driving long LED strings (e.g., >30 white LEDs in series) without cascading converters. |
| Current Sense Threshold | 100mV (typical) at ISP–ISN - sets LED current as ILED = 100mV / RSENSE, minimizing power loss in sense resistor. |
| Switching Frequency Range | 100kHz to 1MHz - adjustable via RT pin resistor; higher frequencies reduce inductor size but increase switching losses. |
| Dimming Ratio | 3000:1 PWM dimming - preserves color fidelity across full brightness range, critical for automotive lighting compliance. |
| Operating Temperature | –40°C to +125°C junction - qualified per AEC-Q100 Grade E, suitable for under-hood and exterior lighting environments. |
| Package | 16-lead MSOP with exposed pad - thermally enhanced for high-power LED driver PCB layouts; GND pad must be soldered. |
Pinout & Package
LT3756EMSE-2#PBF uses a 16-lead plastic MSOP package (3mm × 4.9mm) with exposed thermal pad (Pin 17 = GND). The package is RoHS-compliant, lead-free, and rated for –40°C to +125°C operating junction temperature.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PWMOUT (Pin 1) | Buffered PWM output | Drives external NMOS disconnect switch; toggles low during FB overvoltage (>1.31V) to protect LEDs. |
| FB (Pin 2) | Voltage feedback input | Regulates output voltage to 1.25V; enables CV mode and open-LED detection (pulls OPENLED when FB < 1.20V). |
| 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 input; common-mode range up to 100V; bias current varies with CTRL voltage. |
| VC (Pin 5) | Error amplifier output | Integrates error signal for current/voltage loops; high-impedance during PWM low to retain state. |
| CTRL (Pin 6) | Current threshold control | Sets ISP–ISN threshold: 100mV (full scale) when VCTRL ≥ 1.2V; linear scaling below 1V. |
| VREF (Pin 7) | 2.0V reference output | Stable 2.0V source (±2%) for CTRL divider or temperature compensation networks; drives ≤100µA. |
| PWM (Pin 8) | Digital dimming input | Active-high enable; internal pull-down; controls oscillator, GATE, and PWMOUT; shutdown IQ < 1µA when low. |
| OPENLED (Pin 9) | Open-LED fault indicator | Open-collector output; pulls low when FB < 1.20V (–4% of 1.25V); latched during PWM idle (LT3756-2 feature). |
| SS (Pin 10) | Soft-start timing | 10µA 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 → ~375kHz); no internal pull-up/down. |
| SHDN/UVLO (Pin 12) | Enable & undervoltage lockout | 1.22V falling threshold with 20mV hysteresis; 2.1µA pull-down enables precise VIN brownout setting. |
| INTVCC (Pin 13) | Internal LDO supply | 7.15V regulated output (±150mV); powers gate driver and logic; requires 4.7µF local ceramic bypass. |
| VIN (Pin 14) | Main power input | Accepts 6V–100V; must be bypassed with ≥0.22µF ceramic capacitor near pin; powers INTVCC LDO. |
| 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; 35ns rise/fall into 3.3nF; clamped during fault/shutdown. |
| GND (Pin 17) | Power & signal ground | Exposes thermal pad; connects to negative terminal of SENSE resistor and system ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| High-side current sensing | Enables boost, buck, buck-boost, SEPIC, and flyback topologies without compromising ground-referenced LED cathode/anode placement. |
| Improved OPENLED latching (LT3756-2) | Maintains last valid open-LED fault state during PWM idle, enabling reliable diagnostics in pulsed dimming applications. |
| True-color PWM dimming | 3000:1 ratio achieved via dedicated PWM input and synchronized GATE/PWMOUT control - avoids color shift in automotive lighting. |
| Programmable switching frequency | 100kHz–1MHz via single RT resistor - balances efficiency, EMI, and magnetics size for space-constrained headlamp designs. |
| AEC-Q100 Grade E qualification | Validated for automotive use from –40°C to +125°C; includes HTOL, TC, ESD, and latch-up testing per stress test plan. |
Applications
| Automotive Headlamps | Industrial High-Bay Lighting |
|---|---|
Use Scenario: Adaptive front-lighting system (AFS) with matrix LED arrays requiring precise current control and fast PWM dimming. IC Role / Device Role / Timing Role: Constant-current controller managing individual LED segments; provides open-circuit fault signaling and overvoltage protection. Use Value: Enables 3000:1 dimming without color shift while meeting UNECE R149 photometric requirements for dynamic beam shaping. | Use Scenario: 100W+ LED fixtures for warehouse ceilings operating from 277VAC rectified bus. IC Role / Device Role / Timing Role: Primary DC/DC controller in isolated flyback configuration regulating LED current from high-voltage DC input. Use Value: 100V output capability drives long LED strings directly; high-side sensing avoids ground noise coupling in multi-string parallel architectures. |
| UV-C Sterilization Modules | Streetlight Smart Drivers |
Use Scenario: Pulsed UV-C LED arrays (275nm) used in disinfection cabinets requiring precise current pulses and thermal derating. IC Role / Device Role / Timing Role: Current-source driver with analog dimming (CTRL) and digital enable (PWM) for duty-cycle-controlled irradiation bursts. Use Value: 100mV current sense threshold minimizes power loss in high-current UV LED strings; thermal shutdown protects against LED degradation. | Use Scenario: Outdoor LED streetlights with DALI-2 interface, requiring constant-current output and grid-voltage brownout resilience. IC Role / Device Role / Timing Role: Core LED controller interfaced with microcontroller for adaptive dimming and fault reporting via OPENLED pin. Use Value: SHDN/UVLO pin enables programmable brownout response down to 6V; AEC-Q100 qualification ensures reliability in uncontrolled outdoor environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3756IMSE-2#PBF | Same electrical specs and pinout; rated for –40°C to +125°C industrial temp range (vs. E-grade's same range but tighter initial calibration). | No functional difference in LED driver circuits; identical topology support and dimming performance. | Select for cost-sensitive industrial lighting where AEC-Q100 is not required. |
| LT3756EMSE#PBF | Lacks OPENLED latching and improved open-LED status reporting; base version without -2 enhancements. | Cannot maintain fault state during PWM idle; less robust for diagnostic-heavy automotive applications. | Use only if legacy design compatibility or lower BOM cost outweighs need for latched fault reporting. |
Compared with LT3756IMSE-2#PBF, the LT3756EMSE-2#PBF offers tighter initial parameter tolerances and AEC-Q100 qualification for automotive use; compared with LT3756EMSE#PBF, it adds latched OPENLED behavior essential for accurate fault logging in pulsed-dimming systems.
Availability
LT3756EMSE-2#PBF is available at Aetrix Electronics and suitable for automotive headlamps, industrial high-bay lighting, UV-C sterilization modules, and smart streetlight drivers requiring stable component supply, AEC-Q100 compliance, and high-voltage LED control.
Supply support for LT3756EMSE-2#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 (now part of Analog Devices, Inc., following merger with Maxim Integrated) is a global leader in high-performance analog, mixed-signal, and power management semiconductors.
The LT3756 product line was designed specifically for high-reliability, high-voltage LED current regulation in automotive and industrial environments - emphasizing topology flexibility, fault robustness, and AEC-Q100 qualification.
FAQ
What is the key functional difference between LT3756EMSE-2#PBF and the base LT3756EMSE#PBF?
The LT3756EMSE-2#PBF includes improved open-LED status reporting with latched fault behavior during PWM idle states - meaning the OPENLED pin retains its last valid fault state even when PWM is low. This enables reliable diagnostics in pulsed-dimming applications. The base LT3756EMSE#PBF does not provide this latching function and resets OPENLED state during idle periods. Both share identical pinout, electrical specs, and topology support.
Can LT3756EMSE-2#PBF drive LEDs in buck configuration with high-side current sensing?
Yes, the LT3756EMSE-2#PBF supports buck, boost, buck-boost, SEPIC, and flyback topologies using high-side current sensing via ISP/ISN pins. In buck mode, the LED string connects between input voltage and the switch node, with ISP tied to the LED anode and ISN to the sense resistor top - enabling accurate current regulation independent of ground path noise. This architecture avoids the limitations of low-side sensing in grounded-cathode LED arrangements.
What is the minimum input voltage required for LT3756EMSE-2#PBF to start switching?
The LT3756EMSE-2#PBF requires a minimum input voltage of 6V to initiate switching, as specified in the Electrical Characteristics table. Below 6V, the internal circuitry cannot sustain stable operation of the INTVCC regulator or oscillator. Note that the SHDN/UVLO pin can be configured to hold the device in shutdown until VIN exceeds a higher threshold (e.g., 9V), but the fundamental operational lower limit remains 6V.
How does the CTRL pin affect LED current regulation in LT3756EMSE-2#PBF?
The CTRL pin sets the full-scale current sense threshold between ISP and ISN. When VCTRL ≥ 1.2V, the threshold is fixed at 100mV, so LED current equals 100mV / RSENSE. For 0V < VCTRL < 1V, the threshold scales linearly as (VCTRL – 0.1V) × 10, enabling analog dimming. Between 1V and 1.2V, the transition reaches 98% of full scale by 1.1V. Leaving CTRL unconnected or floating is not allowed - it must be driven or tied to VREF or GND.
Is LT3756EMSE-2#PBF compatible with 277VAC rectified input systems?
Yes, the LT3756EMSE-2#PBF supports input voltages up to 100V, making it suitable for use downstream of a 277VAC rectifier when paired with appropriate front-end stage - such as a bulk capacitor and pre-regulator (e.g., active PFC or buck converter) that reduces the DC bus to ≤100V. Direct connection to 277VAC rectified output (~390VDC) exceeds absolute maximum ratings and will damage the LT3756EMSE-2#PBF. System design must ensure VIN never exceeds 100V under steady-state or transient conditions.
LT3756EMSE-2#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tube
- 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-MSOP-EP
LT3756EMSE-2#PBF FAQ
1.How can I place an order for LT3756EMSE-2#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3756EMSE-2#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 LT3756EMSE-2#PBF reliable?
The price and inventory of LT3756EMSE-2#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3756EMSE-2#PBF is usually 5 days.
3.What payment methods are accepted for LT3756EMSE-2#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3756EMSE-2#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3756EMSE-2#PBF?
LT3756EMSE-2#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3756EMSE-2#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 LT3756EMSE-2#PBF?
For technical support, including LT3756EMSE-2#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3756EMSE-2#PBF requirements.
6.How does Aetrix verify that LT3756EMSE-2#PBF is sourced from the original manufacturer or authorized distributors?
All LT3756EMSE-2#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 LT3756EMSE-2#PBF meets industry standards.
7.What is the process for return or replacement of LT3756EMSE-2#PBF?
All LT3756EMSE-2#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3756EMSE-2#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 LT3756EMSE-2#PBF part is unused and in its original packaging.
Return procedure for LT3756EMSE-2#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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