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Analog Devices Inc. LT3756EMSE-1#PBF
- Part No.:
- LT3756EMSE-1#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3756EMSE-1#PBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:8,455
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Product details
Overview
LT3756EMSE-1#PBF from Analog Devices is a high-voltage DC/DC LED controller IC designed to drive high-current LEDs in boost, buck, or buck-boost topologies. It features 100V input capability, 100V output support, high-side current sensing with 100mV threshold, adjustable switching frequency (100kHz–1MHz), and integrated 7.15V gate driver supply. It is used in automotive LED headlamps requiring robust open-LED protection and 3000:1 PWM dimming.
For engineers reviewing the LT3756EMSE-1#PBF datasheet, LT3756EMSE-1#PBF pinout, LT3756EMSE-1#PBF application, or LT3756EMSE-1#PBF equivalent, key selection considerations include its frequency synchronization capability (LT3756-1 variant), AEC-Q100 qualification for automotive use, high-side current sense architecture, and compatibility with external N-channel MOSFETs in wide-input industrial lighting systems.
Technical Context
The LT3756EMSE-1#PBF implements a fixed-frequency, current-mode control architecture with dual-loop regulation-supporting both constant-current (via ISP/ISN high-side sensing) and constant-voltage (via FB) operation. Its internal 7.15V LDO powers the gate driver and logic, while the SYNC pin enables precise oscillator synchronization to external clock sources.
It integrates programmable undervoltage lockout with hysteresis on SHDN/UVLO, soft-start via SS pin with 10µA pull-up, and fault protection including open-LED detection (FB-based), overvoltage shutdown (FB > VFB + 60mV), and short-circuit detection (ISP–ISN > 150mV at low common-mode).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 6V to 100V - supports 12V/24V/48V industrial and automotive rails with 100V transient tolerance. |
| Output Voltage Capability | Up to 100V - enables single-stage boost for high-string white or UV LEDs without cascaded converters. |
| Current Sense Threshold | 100mV (typ) at ISP–ISN - enables accurate, low-loss high-side LED current regulation with minimal resistor power dissipation. |
| Switching Frequency Range | 100kHz to 1MHz - adjustable via RT resistor; allows optimization of magnetics size, efficiency, and EMI performance. |
| Frequency Synchronization | Yes (SYNC pin) - permits deterministic timing alignment with system clocks or other converters to reduce beat frequencies. |
| Operating Junction Temp | –40°C to 125°C - qualified for under-hood automotive environments and industrial ambient conditions. |
| Package | 16-Lead MSOP - thermally enhanced with exposed pad soldered to PCB ground for reliable power dissipation. |
Pinout & Package
LT3756EMSE-1#PBF is housed in a 16-lead plastic MSOP package with exposed thermal pad (Pin 17 = GND). The package measures 4.0mm × 3.0mm × 0.85mm and is rated for θJA = 43°C/W.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| PWMOUT (1) | Buffered PWM output / Overvoltage fault indicator | Drives external NMOS disconnect switch; pulled low when FB exceeds VFB + 60mV to protect LEDs from overvoltage events. |
| FB (2) | Voltage feedback / Open-LED detection input | Regulates output voltage to 1.25V; asserts OPENLED when FB drops below VFB – 50mV (open LED condition). |
| ISN (3) | Negative current sense input | Connects to low side of high-side sense resistor; bias current <25µA; enables short-circuit detection when ISN < 3V. |
| ISP (4) | Positive current sense input | Connects to high side of sense resistor; combined ISP/ISN bias current <0.1µA in standby; supports 100mV full-scale threshold. |
| VC (5) | Error amplifier output | High-impedance transconductance node; stores demand state during PWM low; requires RC compensation network for loop stability. |
| CTRL (6) | Analog dimming / Current threshold control | Sets ISP–ISN threshold from 0 to 100mV (linear below 1V, constant above 1.2V); enables analog dimming and temperature compensation. |
| VREF (7) | 2.0V reference output | Stable 2.0V ±1.75% reference; supplies up to 100µA; used to bias CTRL divider or implement thermal foldback. |
| PWM (8) | Digital dimming enable | Active-high logic input; disables switching and idles oscillator when low; provides 3000:1 true-color PWM dimming ratio. |
| SYNC (9) | External clock synchronization input | Replaces OPENLED function on LT3756-1 variants; accepts 100kHz–1MHz logic-level signal; requires RT setting 20% slower than SYNC frequency. |
| SS (10) | Soft-start timing control | 10µA internal pull-up to 2.5V rail; external capacitor sets startup ramp time; reset by UVLO or thermal fault. |
| RT (11) | Frequency programming input | Resistor-to-GND sets oscillator frequency; 100kΩ yields ~100kHz, 10kΩ yields ~1MHz per datasheet curve. |
| SHDN/UVLO (12) | Shutdown and input undervoltage detection | 1.22V falling threshold with programmable hysteresis; sub-µA quiescent current in shutdown; resets soft-start on undervoltage event. |
| INTVCC (13) | Internal 7.15V regulator output | Supplies gate driver and logic; requires 4.7µF ceramic bypass; current-limited to ~17mA; includes 4.1V UVLO for FET enhancement safety. |
| VIN (14) | Main input supply | Accepts 6–100V; must be bypassed with ≥0.22µF ceramic capacitor near pin; powers INTVCC LDO and internal circuitry. |
| SENSE (15) | Low-side switch current sense | Kelvin-connected to source of external N-MOSFET; monitors peak switch current; clamped at 108mV to prevent overcurrent. |
| GATE (16) | N-channel MOSFET gate driver | Drives external FET between INTVCC and GND; rise/fall times <35ns into 3.3nF; disabled during shutdown/fault/idle. |
| GND (17) | Power and signal ground / Exposed thermal pad | Reference for all analog circuits and current sense; exposed pad must be soldered to PCB ground plane for thermal and electrical integrity. |
Key Features
| Feature | Design Value |
|---|---|
| High-side current sensing | Enables flexible topology selection (boost/buck/buck-boost/SEPIC/flyback) without ground-referenced LED strings. |
| 3000:1 True Color PWM™ dimming | Preserves LED color consistency across full dimming range via precise duty-cycle control without current modulation artifacts. |
| Programmable frequency synchronization | Eliminates beat frequencies in multi-converter systems and enables deterministic EMI shaping via external clock alignment. |
| AEC-Q100 qualified (Grade E) | Validated for automotive applications including headlamps, DRLs, and interior lighting with guaranteed –40°C to 125°C operation. |
| Integrated open-LED and overvoltage protection | Automatically isolates LED load via PWMOUT-driven NMOS when FB indicates open circuit or overvoltage, preventing damage. |
Applications
| Automotive LED Headlamps | Industrial High-Bay Lighting |
|---|---|
Use Scenario: Driving 40–60V, 1.5A white LED strings in adaptive front-lighting systems (AFS) with dynamic beam shaping. IC Role / Device Role / Timing Role: Constant-current controller managing boost converter stage; synchronizes switching to vehicle CAN clock via SYNC pin for EMI compliance. Use Value: Enables 3000:1 dimming without color shift, meets automotive thermal and reliability requirements, and supports rapid fault response (<10µs) to open-LED events. | Use Scenario: Powering 72V, 700mA UV-C LED arrays in industrial sterilization fixtures operating continuously at 60°C ambient. IC Role / Device Role / Timing Role: High-voltage buck-boost controller regulating LED current despite wide input variation (24–72V AC/DC rectified bus). Use Value: Delivers 94% peak efficiency at full load, maintains regulation across 10:1 input range, and provides fail-safe open-LED reporting to PLC controller via OPENLED pin. |
| Architectural LED Signage | Emergency Exit Lighting |
Use Scenario: Controlling RGBW LED modules in outdoor digital billboards exposed to solar heating and voltage transients. IC Role / Device Role / Timing Role: Constant-current driver with analog dimming (CTRL) and PWM dimming (PWM) for independent channel control and thermal derating. Use Value: Supports 100V input transients, uses VREF to implement temperature-compensated current reduction, and ensures consistent lumen output across –40°C to 85°C. | Use Scenario: Battery-backed LED driver for UL 924-compliant emergency egress lighting operating from 12V lead-acid or LiFePO4 packs. IC Role / Device Role / Timing Role: Buck-mode LED controller with programmable UVLO hysteresis on SHDN/UVLO to extend runtime and prevent brownout oscillation. Use Value: Achieves <1µA shutdown current, regulates LED current precisely at end-of-battery life (down to 6V), and signals battery failure via OPENLED status. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3756EMSE#PBF | No SYNC pin; OPENLED function only; no frequency synchronization capability. | Suitable for standalone LED drivers where EMI coordination or multi-converter timing alignment is not required. | Select when system-level clock sync is unnecessary and cost-sensitive designs prioritize base functionality. |
| LT3756EMSE-2#PBF | Enhanced OPENLED status logic with re-assertion after overvoltage clearance; no SYNC pin. | Better suited for safety-critical lighting where unambiguous open-LED reporting during transient overvoltage events is mandatory. | Choose when robust fault diagnostics under combined overvoltage + open-load conditions are required, especially in medical or transportation lighting. |
Compared with LT3756EMSE#PBF, the LT3756EMSE-1#PBF adds deterministic timing control via SYNC but removes OPENLED; compared with LT3756EMSE-2#PBF, it trades enhanced fault reporting for synchronization-making it optimal for coordinated multi-channel automotive lighting systems requiring EMI coherence.
Availability
LT3756EMSE-1#PBF is available at Aetrix Electronics and suitable for automotive LED headlamps, industrial high-bay lighting, and architectural signage requiring stable component supply, AEC-Q100 compliance, and synchronized multi-converter operation.
Supply support for LT3756EMSE-1#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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving precision instrumentation, industrial automation, and automotive markets.
The LT3756 product line was engineered specifically for high-reliability, high-voltage LED driving applications-emphasizing topology flexibility, robust fault protection, and automotive-grade thermal and EMC performance.
FAQ
What is the primary function of the SYNC pin on the LT3756EMSE-1#PBF?
The SYNC pin on the LT3756EMSE-1#PBF allows external synchronization of the internal oscillator to a system clock or another converter's switching signal. It replaces the OPENLED function found on non–1 variants. To ensure stable locking, the RT resistor must be selected to set the internal frequency ~20% lower than the SYNC signal frequency. This capability is exclusive to the LT3756-1 family, including the LT3756EMSE-1#PBF, and is critical for reducing beat frequencies in multi-channel LED systems.
How does the LT3756EMSE-1#PBF support both constant-current and constant-voltage regulation?
The LT3756EMSE-1#PBF supports dual-loop regulation using separate feedback paths: high-side current sensing (ISP/ISN) for constant-current mode and the FB pin for constant-voltage mode. When ISP and ISN sense LED current, the error amplifier adjusts peak switch current to maintain the CTRL-set threshold. Simultaneously, the FB loop compares output voltage to an internal 1.25V reference. The two loops interact-FB limits maximum output voltage while ISP/ISN governs current-enabling safe operation in both modes. The LT3756EMSE-1#PBF retains full CV/CC capability despite its SYNC pin implementation.
What is the recommended layout practice for the exposed thermal pad on the LT3756EMSE-1#PBF MSOP package?
The exposed thermal pad (Pin 17) on the LT3756EMSE-1#PBF must be soldered directly to a solid PCB ground plane using a minimum of 9 thermal vias (0.3mm diameter, spaced ≤1mm apart) filled or capped. This ensures effective heat transfer and maintains θJA = 43°C/W. The pad should be connected exclusively to GND-no signal traces or split planes-and the surrounding solder mask should be removed to maximize copper contact area. Failure to properly thermally anchor the pad risks junction temperature exceeding 125°C under sustained 30W operation.
Can the LT3756EMSE-1#PBF drive LEDs in buck configuration with high-side current sensing?
Yes-the LT3756EMSE-1#PBF supports buck-mode operation with high-side current sensing, enabling the LED string to remain referenced to system ground for simplified thermal management and photometric measurement. In buck mode, the ISP/ISN inputs monitor current through a sense resistor placed between the input rail and the LED anode, while the GATE driver controls the low-side N-MOSFET. This architecture avoids the need for level-shifting circuitry and maintains the same 100mV current sense threshold and protection features as in boost mode. The LT3756EMSE-1#PBF's topology flexibility is explicitly confirmed in its datasheet Applications section.
What is the minimum recommended input capacitance for the VIN pin of the LT3756EMSE-1#PBF?
The VIN pin of the LT3756EMSE-1#PBF requires a minimum local bypass capacitance of 0.22µF ceramic (X7R/X5R, 10V rating), placed within 2mm of the pin with direct low-inductance connection to the exposed GND pad. For systems with long input traces or high di/dt loads, a bulk capacitor (e.g., 10µF tantalum or polymer) should be added upstream. This ensures stable operation during fast load transients and suppresses high-frequency noise that could couple into the sensitive ISP/ISN or FB nodes. The LT3756EMSE-1#PBF's absolute maximum VIN rating remains 100V regardless of input capacitance value.
LT3756EMSE-1#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-1#PBF FAQ
1.How can I place an order for LT3756EMSE-1#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3756EMSE-1#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-1#PBF reliable?
The price and inventory of LT3756EMSE-1#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-1#PBF is usually 5 days.
3.What payment methods are accepted for LT3756EMSE-1#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3756EMSE-1#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3756EMSE-1#PBF?
LT3756EMSE-1#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3756EMSE-1#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-1#PBF?
For technical support, including LT3756EMSE-1#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3756EMSE-1#PBF requirements.
6.How does Aetrix verify that LT3756EMSE-1#PBF is sourced from the original manufacturer or authorized distributors?
All LT3756EMSE-1#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-1#PBF meets industry standards.
7.What is the process for return or replacement of LT3756EMSE-1#PBF?
All LT3756EMSE-1#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3756EMSE-1#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-1#PBF part is unused and in its original packaging.
Return procedure for LT3756EMSE-1#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3756EMSE-1#PBF Tags
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