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Analog Devices Inc. LT3755HMSE-2#PBF
- Part No.:
- LT3755HMSE-2#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3755HMSE-2#PBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,887
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Product details
Overview
LT3755HMSE-2#PBF from Analog Devices is a constant-frequency, current-mode DC/DC LED controller optimized for high-power automotive and industrial LED drivers. It drives an external low-side N-channel MOSFET, supports boost/buck/buck-boost/SEPIC/flyback topologies, delivers up to 75V output, senses LED current at the high side with 100mV threshold, and features true-color PWM dimming up to 3000:1 - deployed in 50W white automotive headlamp systems.
For engineers reviewing the LT3755HMSE-2#PBF datasheet, LT3755HMSE-2#PBF pinout, LT3755HMSE-2#PBF application, or LT3755HMSE-2#PBF equivalent, key selection considerations include its AEC-Q100 qualification, –40°C to 150°C junction temperature rating, high-side current sensing architecture, open-LED protection via FB-based fault detection, and programmable switching frequency (100kHz–1MHz) for EMI and magnetics optimization.
Technical Context
The LT3755HMSE-2#PBF implements a fixed-frequency current-mode control architecture with internal 7.15V INTVCC regulator powering the gate driver and logic. Its error amplifier (VC) regulates either LED current via ISP/ISN differential sensing or output voltage via FB, with dual-loop interaction managed by transconductance amplifiers and slope compensation.
It integrates dedicated protection circuitry: OPENLED status assertion when FB drops 50mV below 1.25V (LT3755-2 variant), ISP/ISN short-circuit detection active below 3V common-mode voltage, and programmable UVLO on SHDN/UVLO with 20mV hysteresis. The CTRL pin linearly adjusts current sense threshold from 0V to 1V, then holds at 100mV full-scale above 1.2V.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 40V - supports wide automotive battery range including cold-crank (4.5V) and load-dump (40V) conditions. |
| Output Voltage Capability | Up to 75V - enables driving long series strings of high-brightness LEDs in headlamp and signage applications. |
| Current Sense Threshold | 100mV (typical) at ISP–ISN - enables precise, low-loss high-side LED current regulation with minimal power dissipation. |
| Switching Frequency Range | 100kHz to 1MHz - adjustable via RT resistor to balance efficiency, EMI, and magnetic component size. |
| Operating Junction Temp | –40°C to +150°C - H-grade rating meets AEC-Q100 Grade 0 requirements for under-hood automotive deployment. |
| PWM Dimming Ratio | 3000:1 - supports high-fidelity, flicker-free brightness control essential for adaptive front-lighting systems (AFS). |
| Shutdown Current | <1µA - ensures ultra-low quiescent draw during vehicle sleep mode to prevent battery drain. |
Pinout & Package
LT3755HMSE-2#PBF is housed in a thermally enhanced 16-lead plastic MSOP package (3mm × 4.9mm) with exposed pad (Pin 17) soldered to PCB ground for thermal and electrical integrity. The package supports high-power density designs in space-constrained automotive modules.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PWMOUT (Pin 1) | Buffered PWM output | Drives NMOS disconnect switch; toggles low during FB overvoltage (>1.25V + 60mV) to isolate LED load and prevent damage. |
| FB (Pin 2) | Voltage feedback input | Ground-referenced node regulating output voltage to 1.25V; triggers OPENLED pull-down when <1.20V (LT3755-2 behavior). |
| ISN (Pin 3) | Negative current sense input | High-side current sense return; enables short-circuit detection below 3V common-mode voltage. |
| ISP (Pin 4) | Positive current sense input | High-side current sense input; combined with ISN, sets LED current via 100mV threshold or CTRL-adjusted value. |
| VC (Pin 5) | Error amplifier output | Integrates difference between ISP–ISN and CTRL-set threshold; stabilizes loop with external RC network. |
| CTRL (Pin 6) | Current threshold adjust | Linearly scales ISP–ISN threshold from 0V to 1V (10× gain), then clamps at 100mV for analog dimming or thermal derating. |
| VREF (Pin 7) | 2.0V reference output | Stable 2.0V source (±2%) for biasing CTRL divider or temperature compensation networks; supplies ≤100µA. |
| PWM (Pin 8) | Digital dimming input | Active-high enable; forces GATE/PWMOUT low and places VC in high-Z storage mode during off periods. |
| OPENLED (Pin 9) | Open-LED fault indicator | Open-collector output pulled low when FB < 1.20V (LT3755-2); requires external pull-up <1mA for fault reporting. |
| SS (Pin 10) | Soft-start control | 10µA internal pull-up to 2.5V rail; external capacitor sets ramp time; reset by UVLO or thermal shutdown. |
| RT (Pin 11) | Frequency programming | Resistor-to-GND sets oscillator frequency; 100kΩ yields ~375kHz per datasheet curve. |
| SHDN/UVLO (Pin 12) | Enable & undervoltage detect | 1.22V falling threshold with programmable hysteresis; sub-µA bias above threshold; pulls down 2.1µA below to set hysteresis. |
| INTVCC (Pin 13) | Internal LDO output | 7.15V regulated supply (±150mV) for gate driver and logic; requires 4.7µF local ceramic bypass. |
| VIN (Pin 14) | Main input supply | Accepts 4.5V–40V; powers INTVCC LDO and internal circuits; bypass with ≥0.22µF ceramic near pin. |
| SENSE (Pin 15) | Low-side current sense | Kelvin-connected to FET source; monitors switch current for cycle-by-cycle limiting at 108mV threshold. |
| GATE (Pin 16) | NMOS gate driver | Drives external low-side FET between INTVCC and GND; rise/fall time <35ns into 3300pF. |
| Exposed Pad (Pin 17) | Thermal & electrical ground | Mandatory solder connection to PCB ground plane; improves thermal resistance (θJC = 4°C/W) and reduces noise coupling. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 Qualified (H-grade) | Validated for automotive under-hood operation up to 150°C junction temperature with robust HTOL and TC testing. |
| High-Side Current Sensing | Enables flexible topology selection (boost/buck/buck-boost/SEPIC/flyback) without compromising ground-referenced LED cathode placement. |
| True Color PWM™ Dimming | 3000:1 ratio preserves LED spectral consistency across brightness levels - critical for automotive lighting compliance and visual quality. |
| Integrated Open-LED Protection | FB-based fault detection asserts OPENLED pin when LED string opens, enabling system-level fault logging and fail-safe response. |
| Programmable Undervoltage Lockout | External resistor divider + internal 2.1µA pull-down enables precise, hysteresis-controlled startup/shutdown sequencing in 12V/24V systems. |
| Thermally Enhanced MSOP | Exposed pad design achieves θJA = 43°C/W - enables >50W LED drive capability in compact surface-mount footprint. |
Applications
| Automotive Headlamp Driver | Industrial High-Bay Lighting |
|---|---|
Use Scenario: 50W white LED headlamp module in passenger vehicle front lighting system requiring adaptive beam shaping and dynamic dimming. IC Role / Device Role / Timing Role: Constant-current LED controller managing boost converter with high-side current sensing and synchronized PWM dimming. Use Value: AEC-Q100 H-grade rating ensures reliability at 150°C junction; 3000:1 PWM dimming enables smooth, flicker-free beam modulation for AFS functions. | Use Scenario: High-bay LED fixture in warehouse or factory environment demanding high lumen output, long life, and robust thermal management. IC Role / Device Role / Timing Role: Primary DC/DC controller regulating multi-string LED arrays in buck-boost configuration with programmable soft-start. Use Value: 75V output capability supports long LED strings; high-side sensing simplifies layout and improves EMC performance in metal-enclosed fixtures. |
| Battery-Powered LED Spotlight | UV-C Disinfection Module |
Use Scenario: Portable, rechargeable LED spotlight using Li-ion battery pack (8–16V) with variable brightness and runtime optimization. IC Role / Device Role / Timing Role: Efficient boost LED driver with ultra-low shutdown current (<1µA) and analog dimming via CTRL pin for battery conservation. Use Value: 4.5V minimum VIN enables operation down to deeply discharged battery; programmable frequency allows trade-off between efficiency and inductor size. | Use Scenario: Compact UV-C LED array used for surface disinfection in medical or consumer devices, requiring precise current control and safety interlocks. IC Role / Device Role / Timing Role: Constant-current driver with open-LED and short-circuit protection, interfaced to microcontroller via OPENLED and PWM pins. Use Value: ISP/ISN short-circuit detection below 3V common-mode prevents false trips during UV-C LED turn-on transients; FB-based open-LED reporting enables system fault isolation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3756HMSE-2#PBF | Higher 100V output capability; identical pinout, package, and feature set except extended ISP/ISN common-mode range (up to 100V). | Suitable for higher-voltage LED strings (e.g., >75V) or flyback configurations with higher reflected voltages. | Select when output voltage exceeds 75V or when operating in flyback with >75V reflected primary voltage. |
| LM3410XSDX/NOPB | Single-stage boost-only controller; lower 36V max VIN; no high-side current sensing; lacks OPENLED, SYNC, or CTRL analog dimming. | Targeted at cost-sensitive, low-power (<10W) portable LED applications without automotive or high-reliability requirements. | Choose only for non-automotive, low-complexity boost LED drivers where AEC-Q100, topology flexibility, and protection features are not required. |
Compared with LT3755HMSE-2#PBF, LT3756HMSE-2#PBF extends safe operation to 100V outputs while maintaining drop-in compatibility, whereas LM3410XSDX/NOPB offers simplified, lower-cost boost control but omits critical automotive protections, high-side sensing, and multi-topology support.
Availability
LT3755HMSE-2#PBF is available at Aetrix Electronics and suitable for automotive headlamp systems, industrial high-bay lighting, battery-powered spotlights, and UV-C disinfection modules requiring stable component supply, AEC-Q100 compliance, and high-temperature operation.
Supply support for LT3755HMSE-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 is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving automotive, industrial, communications, and healthcare markets.
The LT3755 family is designed specifically for high-efficiency, high-reliability LED driver applications - emphasizing wide input range, flexible topology support, integrated protection, and AEC-Q100 qualification for automotive lighting.
FAQ
What is the maximum output voltage supported by the LT3755HMSE-2#PBF?
The LT3755HMSE-2#PBF supports output voltages up to 75V, enabling it to drive long series strings of high-brightness LEDs commonly used in automotive headlamps and industrial lighting. This rating is specified in the Absolute Maximum Ratings table and confirmed in the Applications section, where a 50W white automotive LED headlamp driver is shown operating within this limit.
Does the LT3755HMSE-2#PBF support AEC-Q100 qualification?
Yes, the LT3755HMSE-2#PBF is AEC-Q100 qualified for automotive applications. Its H-grade temperature rating (–40°C to +150°C junction) and associated reliability testing meet AEC-Q100 Grade 0 requirements. This is explicitly stated in the FEATURES list and ORDER INFORMATION table, where "LT3755HMSE-2#PBF" is listed with "–40°C to 150°C" and "AUTOMOTIVE PRODUCTS" designation.
How does the OPENLED pin function on the LT3755HMSE-2#PBF?
The OPENLED pin on the LT3755HMSE-2#PBF is an open-collector output that asserts (pulls low) when the FB voltage falls below 1.20V (i.e., 50mV below the 1.25V regulation threshold), indicating an open LED string. As an LT3755-2 variant, it re-asserts OPENLED after FB drops below the overvoltage threshold and remains above the OPENLED threshold - a behavior distinct from the base LT3755. An external pull-up current <1mA is required.
Can the LT3755HMSE-2#PBF operate in buck, boost, and buck-boost topologies?
Yes, the LT3755HMSE-2#PBF supports boost, buck, buck-boost, SEPIC, and flyback topologies. Its high-side current sensing architecture (via ISP/ISN) decouples the LED string from ground, allowing flexible configuration regardless of input/output voltage relationship. This is explicitly listed under FEATURES and confirmed in the DESCRIPTION section and TYPICAL APPLICATION diagrams.
What is the purpose of the CTRL pin on the LT3755HMSE-2#PBF?
The CTRL pin on the LT3755HMSE-2#PBF adjusts the ISP–ISN current sense threshold: from 0V to 1V, it provides linear 10× scaling (e.g., 0.5V → 50mV threshold); above 1.2V, it clamps at the full-scale 100mV value. This enables analog dimming, thermal derating, or closed-loop current adjustment - a core feature documented in PIN FUNCTIONS and ELECTRICAL CHARACTERISTICS tables.
LT3755HMSE-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):
- 4.5V
- Voltage - Supply (Max):
- 40V
- Voltage - Output:
- -
- Current - Output / Channel:
- -
- Frequency:
- 100kHz ~ 1MHz
- Dimming:
- Analog, PWM
- Applications:
- -
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LT3755HMSE-2#PBF FAQ
1.How can I place an order for LT3755HMSE-2#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3755HMSE-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 LT3755HMSE-2#PBF reliable?
The price and inventory of LT3755HMSE-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 LT3755HMSE-2#PBF is usually 5 days.
3.What payment methods are accepted for LT3755HMSE-2#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3755HMSE-2#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3755HMSE-2#PBF?
LT3755HMSE-2#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3755HMSE-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 LT3755HMSE-2#PBF?
For technical support, including LT3755HMSE-2#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3755HMSE-2#PBF requirements.
6.How does Aetrix verify that LT3755HMSE-2#PBF is sourced from the original manufacturer or authorized distributors?
All LT3755HMSE-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 LT3755HMSE-2#PBF meets industry standards.
7.What is the process for return or replacement of LT3755HMSE-2#PBF?
All LT3755HMSE-2#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3755HMSE-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 LT3755HMSE-2#PBF part is unused and in its original packaging.
Return procedure for LT3755HMSE-2#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3755HMSE-2#PBF Tags
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