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Analog Devices Inc. LT3755JMSE-2#WPBF
- Part No.:
- LT3755JMSE-2#WPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3755JMSE-2#WPBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,480
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Product details
Overview
LT3755JMSE-2#WPBF from Analog Devices is a constant-frequency, current-mode DC/DC LED controller optimized for automotive-grade high-power LED drivers. It operates as a constant-current source with 100 mV high-side current sense threshold, supports 4.5V–40V input and up to 75V output, and delivers true-color PWM dimming up to 3000:1 in boost/buck/buck-boost topologies. Used in 50W white automotive LED headlamp drivers.
For engineers reviewing the LT3755JMSE-2#WPBF datasheet, LT3755JMSE-2#WPBF pinout, LT3755JMSE-2#WPBF application, or LT3755JMSE-2#WPBF equivalent, key selection criteria include its AEC-Q100 qualification, –40°C to +150°C junction temperature rating, open LED protection via OPENLED pin, adjustable 100 kHz–1 MHz switching frequency, and dual-loop (constant-current + constant-voltage) regulation capability.
Technical Context
The LT3755JMSE-2#WPBF implements fixed-frequency current-mode control with internal 7.15 V regulated INTVCC supply driving an external low-side N-channel MOSFET. Its high-side current sensing architecture (via ISP/ISN pins) enables flexible topology support including boost, buck, buck-boost, SEPIC, and flyback configurations without requiring ground-referenced LED strings.
It features dual feedback loops: one for LED current regulation (using CTRL-adjustable 100 mV threshold and ISP/ISN differential sensing), and another for voltage regulation (FB pin referenced to 1.25 V nominal). The LT3755-2 variant adds improved OPENLED status reporting with re-assertion behavior after overvoltage recovery, distinguishing it from LT3755 and LT3755-1.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5 V to 40 V - supports wide automotive battery range including cold-crank (4.5 V) and load-dump transients (up to 40 V). |
| Output Voltage Capability | Up to 75 V - enables driving long LED strings in headlamp and DRL applications. |
| Current Sense Threshold | 100 mV (typical) at ISP–ISN - sets precise LED current with minimal power loss in sense resistor. |
| Switching Frequency Range | 100 kHz to 1 MHz - programmable via RT resistor to balance efficiency, EMI, and magnetics size. |
| Operating Junction Temp | –40°C to +150°C - J-grade rating meets AEC-Q100 Grade 0 requirements for under-hood automotive use. |
| PWM Dimming Ratio | 3000:1 - enables high-fidelity brightness control without color shift in automotive lighting. |
| Open LED Detection | FB threshold minus 50 mV - activates OPENLED pull-down to signal LED string disconnection while maintaining safe shutdown behavior. |
Pinout & Package
LT3755JMSE-2#WPBF uses a thermally enhanced 16-lead plastic MSOP package (3 mm × 4.9 mm) with exposed pad (Pin 17) soldered to PCB ground for thermal and electrical integrity. Pin numbering follows standard MSOP top-view orientation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PWMOUT (Pin 1) | Buffered PWM output | Drives NMOS disconnect switch; toggles low during FB overvoltage (>VFB + 60 mV) to isolate LED load. |
| FB (Pin 2) | Voltage feedback input | Regulates output voltage to 1.25 V nominal; enables open LED detection and CV mode operation. |
| ISN (Pin 3) | Negative current sense input | High-side current sense return; enables short-circuit detection when ISN < 3 V. |
| ISP (Pin 4) | Positive current sense input | High-side current sense input; bias current varies with CTRL voltage per datasheet curve. |
| VC (Pin 5) | Error amplifier output | Integrates error signal for loop stability; high-impedance during PWM low to retain state. |
| CTRL (Pin 6) | Current threshold adjust | Sets ISP–ISN threshold from 0 mV to 100 mV linearly (0–1 V), then clamps at full scale (>1.2 V). |
| VREF (Pin 7) | 2 V reference output | Supplies ≤100 µA for CTRL divider or temperature compensation networks. |
| PWM (Pin 8) | Digital dimming input | Active-low enable; internally pulled down; controls PWMOUT and oscillator wake-up. |
| OPENLED (Pin 9) | Open LED fault indicator | Open-collector output asserting low when FB < (VFB – 50 mV); latched during PWM low. |
| SS (Pin 10) | Soft-start control | 10 µA pull-up to 2.5 V rail; external capacitor sets ramp time; reset by UVLO or thermal fault. |
| RT (Pin 11) | Frequency programming | Resistor-to-GND sets oscillator frequency; 100 kΩ → ~375 kHz (per typical curve). |
| SHDN/UVLO (Pin 12) | Shutdown & input monitoring | 1.22 V falling threshold with programmable hysteresis; sub-µA bias above threshold. |
| INTVCC (Pin 13) | Internal LDO output | 7.15 V regulated supply for gate driver and logic; requires 4.7 µF local ceramic bypass. |
| VIN (Pin 14) | Main input supply | Accepts 4.5–40 V; powers INTVCC LDO and internal circuitry; bypass with ≥0.22 µF ceramic. |
| SENSE (Pin 15) | Low-side current sense | Kelvin-connected to FET source; monitors switch current for slope-compensated current-mode control. |
| GATE (Pin 16) | NMOS gate driver | Swings between INTVCC and GND; drives external low-side N-channel MOSFET gate. |
| Exposed Pad (Pin 17) | Thermal & electrical ground | Must be soldered to PCB ground plane; provides primary thermal path and GND reference. |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 qualified | J-grade (–40°C to +150°C) ensures reliability for automotive under-hood LED headlamp systems. |
| High-side current sensing | Enables topology flexibility (boost/buck/buck-boost) without grounding LED cathode, simplifying thermal layout. |
| True-color PWM dimming | 3000:1 ratio preserves LED chromaticity across full brightness range-critical for adaptive driving beam (ADB) systems. |
| Improved OPENLED status logic | LT3755-2 re-asserts OPENLED after FB recovers from overvoltage, enabling robust fault diagnostics in safety-critical lighting. |
| Programmable soft-start | External capacitor on SS pin prevents inrush current and stabilizes startup in high-power LED arrays. |
| Integrated 7.15 V LDO | Powers gate driver and logic independently of VIN fluctuations-maintains gate drive strength during cold-crank events. |
Applications
| Automotive LED Headlamps | Battery-Powered LED Lighting |
|---|---|
Use Scenario: High-intensity white LED arrays in adaptive front-lighting systems (AFS) requiring precise current regulation and thermal resilience. IC Role / Device Role / Timing Role: Constant-current controller managing boost converter driving 12–24 V input to 48–72 V LED string with real-time dimming and fault reporting. Use Value: AEC-Q100 J-grade operation ensures stable performance at 150°C junction temperature; OPENLED pin enables ASIL-B compatible fault signaling. | Use Scenario: Portable medical devices or handheld inspection tools using high-brightness LEDs powered by Li-ion batteries (3.0–4.2 V/cell). IC Role / Device Role / Timing Role: Buck-mode LED driver regulating current from single/dual-cell battery packs into high-efficiency LED loads. Use Value: Wide 4.5–40 V input range accommodates battery voltage sag and charging transients; 100 mV sense threshold minimizes power loss in compact layouts. |
| Industrial Machine Vision Lighting | Architectural LED Drivers |
Use Scenario: Stroboscopic LED arrays in factory automation cameras requiring microsecond-level PWM timing accuracy and repeatable intensity. IC Role / Device Role / Timing Role: Synchronized constant-current source delivering 3000:1 dimming with minimal jitter across multiple parallel LED channels. Use Value: Fixed-frequency current-mode architecture ensures stable loop response; RT pin allows EMI-optimized frequency selection for noise-sensitive imaging environments. | Use Scenario: Outdoor architectural signage with long LED strings operating from 24/48 V DC distribution rails in variable ambient temperatures. IC Role / Device Role / Timing Role: Boost-mode controller regulating current into 60+ V LED strings with open-circuit protection and thermal derating. Use Value: 75 V output capability supports extended LED chains; high-side sensing avoids ground-loop interference in distributed installations. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3783EFE#PBF | Fixed 500 kHz frequency; no RT pin; supports only boost/buck-boost; lacks OPENLED pin and CTRL-based analog dimming. | Targeted at simpler, cost-sensitive industrial LED drivers-not AEC-Q100 qualified or rated for >125°C. | Select when fixed frequency suffices and automotive qualification is unnecessary. |
| LM3410XMF/NOPB | Single-stage buck-only controller; max 32 V output; no high-side sensing; 1.25 V FB reference only-no ISP/ISN inputs. | Designed for low-power portable LED flashlights (<5 W), not multi-watt headlamps or high-voltage strings. | Choose only for low-cost, low-power buck applications where topology and voltage headroom are constrained. |
Compared with LTC3783EFE#PBF and LM3410XMF/NOPB, LT3755JMSE-2#WPBF uniquely combines AEC-Q100 J-grade reliability, programmable 100 kHz–1 MHz switching, high-side current sensing for topology flexibility, and dual-loop (CC/CV) regulation-making it the sole option qualified for demanding automotive LED headlamp designs.
Availability
LT3755JMSE-2#WPBF is available at Aetrix Electronics and suitable for automotive LED headlamps, industrial machine vision lighting, and high-reliability battery-powered LED systems requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT3755JMSE-2#WPBF 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, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT3755 family is designed specifically for high-power LED driver applications requiring precision current regulation, wide input/output voltage capability, and robust fault protection-targeting automotive lighting, architectural LED systems, and industrial illumination.
FAQ
What is the maximum junction temperature rating for LT3755JMSE-2#WPBF?
The LT3755JMSE-2#WPBF is rated for operation from –40°C to +150°C junction temperature, meeting AEC-Q100 Grade 0 requirements. This J-grade specification ensures reliable performance in under-hood automotive environments where ambient temperatures exceed 105°C and thermal cycling is severe. The LT3755JMSE-2#WPBF achieves this via process and packaging enhancements validated per automotive reliability test standards.
How does the OPENLED pin function differ on LT3755JMSE-2#WPBF versus earlier variants?
The LT3755JMSE-2#WPBF implements improved OPENLED status logic: it re-asserts the OPENLED pull-down after FB falls below the overvoltage threshold (VFB + 60 mV) while remaining above the open LED threshold (VFB – 50 mV). In contrast, the base LT3755 holds OPENLED de-asserted until FB drops below both thresholds. This behavior enables more accurate fault diagnosis in automotive safety systems. The LT3755JMSE-2#WPBF datasheet confirms this distinction in the OPERATION section.
Can LT3755JMSE-2#WPBF operate in buck configuration with a grounded LED cathode?
Yes, LT3755JMSE-2#WPBF supports buck topology with grounded LED cathode by connecting the LED string between VIN and the switch node (driven by external MOSFET), while using high-side current sensing via ISP/ISN. However, the IC's primary advantage lies in high-side sensing, which decouples LED string grounding from the controller's ground reference-enabling boost, buck-boost, SEPIC, and flyback topologies without compromising noise immunity or layout constraints. The LT3755JMSE-2#WPBF datasheet explicitly lists all five topologies in its FEATURES section.
What is the purpose of the CTRL pin on LT3755JMSE-2#WPBF, and how is it used?
The CTRL pin on LT3755JMSE-2#WPBF adjusts the ISP–ISN current sense threshold from 0 mV to 100 mV (typical) in a linear relationship with VCTRL (0–1 V), then clamps at full scale above 1.2 V. It enables analog dimming, temperature compensation (when driven from VREF), or closed-loop current trimming. For example, applying 0.5 V to CTRL sets the threshold to ~50 mV, halving LED current for a given sense resistor. The LT3755JMSE-2#WPBF Electrical Characteristics table specifies ±3% linearity and 100 nA input bias for accurate implementation.
Is LT3755JMSE-2#WPBF pin-compatible with other LT3755-2 variants like LT3755EMSE-2#WPBF?
Yes, LT3755JMSE-2#WPBF is pin-compatible with all MSOP-packaged LT3755-2 variants-including LT3755EMSE-2#WPBF and LT3755IMSE-2#WPBF-as confirmed by identical pin configuration diagrams and package descriptions in the datasheet. The only differences are temperature grade (J-grade = –40°C to +150°C vs E/I-grade = –40°C to +125°C) and part marking (37552). No PCB layout changes are required when upgrading from E/I to J grade for enhanced thermal robustness.
LT3755JMSE-2#WPBF 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:
- General Purpose
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LT3755JMSE-2#WPBF FAQ
1.How can I place an order for LT3755JMSE-2#WPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3755JMSE-2#WPBF 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 LT3755JMSE-2#WPBF reliable?
The price and inventory of LT3755JMSE-2#WPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3755JMSE-2#WPBF is usually 5 days.
3.What payment methods are accepted for LT3755JMSE-2#WPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3755JMSE-2#WPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3755JMSE-2#WPBF?
LT3755JMSE-2#WPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3755JMSE-2#WPBF 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 LT3755JMSE-2#WPBF?
For technical support, including LT3755JMSE-2#WPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3755JMSE-2#WPBF requirements.
6.How does Aetrix verify that LT3755JMSE-2#WPBF is sourced from the original manufacturer or authorized distributors?
All LT3755JMSE-2#WPBF 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 LT3755JMSE-2#WPBF meets industry standards.
7.What is the process for return or replacement of LT3755JMSE-2#WPBF?
All LT3755JMSE-2#WPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3755JMSE-2#WPBF, 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 LT3755JMSE-2#WPBF part is unused and in its original packaging.
Return procedure for LT3755JMSE-2#WPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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