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Analog Devices Inc. LT3755HMSE-2#TRPBF
- Part No.:
- LT3755HMSE-2#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3755HMSE-2#TRPBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,490
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Product details
Overview
LT3755HMSE-2#TRPBF from Analog Devices is a high-voltage, constant-current DC/DC LED controller optimized for automotive headlamp and industrial high-power LED drivers. It operates from 4.5V to 40V input, delivers up to 75V output, supports 3000:1 PWM dimming, drives external N-channel MOSFETs via a 7.15V INTVCC gate driver, and features high-side current sensing for boost/buck/buck-boost topologies - deployed in 50W white LED automotive headlamps.
For engineers reviewing the LT3755HMSE-2#TRPBF datasheet, LT3755HMSE-2#TRPBF pinout, LT3755HMSE-2#TRPBF application, or LT3755HMSE-2#TRPBF equivalent, key selection criteria include its AEC-Q100 H-grade (–40°C to +150°C), open LED protection with OPENLED status pin, programmable 100kHz–1MHz switching frequency, 100mV high-side current sense threshold, and dual-loop (constant-current + constant-voltage) regulation capability.
Technical Context
The LT3755HMSE-2#TRPBF implements fixed-frequency current-mode control with internal slope compensation, using a transconductance error amplifier (VC pin) to regulate either LED string current (via ISP/ISN differential sensing) or output voltage (via FB pin). Its architecture enables seamless transition between CC and CV modes without external mode-switching circuitry.
It integrates an internal 7.15V LDO (INTVCC) for gate driving, supports analog dimming via CTRL pin (0–1.1V adjusts current threshold from 0 to 100mV), and provides dedicated fault handling: OPENLED pull-down asserts when FB drops 50mV below 1.25V reference (LT3755-2 variant), while PWMOUT forces low during FB overvoltage events (>1.31V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 40V - supports wide automotive battery range including cold-crank (6V) and load-dump (36V+) |
| Output Voltage Capability | Up to 75V - enables series strings of >20 white LEDs (3.2V each) in boost configuration |
| Current Sense Threshold | 100mV (typical) at ISP–ISN - sets LED current as ILED = 100mV / Rsense, enabling precise ±3% current regulation |
| Switching Frequency Range | 100kHz to 1MHz - adjustable via RT resistor; higher frequencies reduce inductor size but increase switching loss |
| Operating Junction Temp | –40°C to +150°C - H-grade qualification ensures reliability in under-hood automotive environments |
| Dimming Ratio | 3000:1 true-color PWM dimming - preserves LED chromaticity across full brightness range without color shift |
| Open LED Detection | FB-based detection with OPENLED pin assertion at VFB < 1.20V (1.25V – 50mV) - provides fail-safe status signaling for safety-critical lighting |
Pinout & Package
LT3755HMSE-2#TRPBF 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 dissipation and current-sense return path. Pin numbering follows standard MSOP top-view orientation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PWMOUT (Pin 1) | Buffered PWM output / Fault indicator | Drives NMOS disconnect switch; pulled low during FB overvoltage (>1.31V) to isolate LED load and prevent damage |
| FB (Pin 2) | Voltage feedback input | Regulates output voltage to 1.25V; also triggers OPENLED status and PWMOUT fault response based on deviation thresholds |
| ISN (Pin 3) | Negative current sense input | High-side current sensing node; common-mode range 2.9V–75V; enables short-circuit detection when ISN < 3V |
| ISP (Pin 4) | Positive current sense input | Paired with ISN; differential voltage (ISP–ISN) sets LED current; bias current varies with CTRL voltage |
| VC (Pin 5) | Error amplifier output | Integrates loop error; high-impedance during PWM low to retain state; requires RC compensation network for stability |
| CTRL (Pin 6) | Analog dimming / current threshold control | Adjusts ISP–ISN threshold from 0 to 100mV linearly (0–1V), then clamps at full scale (>1.2V); enables temperature-compensated dimming |
| VREF (Pin 7) | 2.0V precision reference output | Supplies ≤100µA; used to bias CTRL divider or enable thermal foldback via NTC network |
| PWM (Pin 8) | Digital dimming input | Active-high logic input; internal pull-down; controls switching enable/disable and resets OPENLED latch on rising edge |
| OPENLED (Pin 9) | Open-circuit fault indicator | Open-drain output; pulls low when FB < 1.20V (LT3755-2 specific); requires external pull-up <1mA |
| SS (Pin 10) | Soft-start timing input | 10µA internal current charges external capacitor; sets startup ramp time and prevents inrush current |
| RT (Pin 11) | Frequency programming input | Resistor-to-GND sets oscillator frequency (100kΩ → ~375kHz); determines trade-off between efficiency and magnetics size |
| SHDN/UVLO (Pin 12) | Shutdown and input UVLO input | 1.22V falling threshold with programmable hysteresis; disables IC and reduces IQ to <1µA when pulled ≤0.4V |
| INTVCC (Pin 13) | Internal regulated supply | 7.15V LDO output; powers GATE/PWMOUT drivers; requires 4.7µF local ceramic bypass; current-limited to 34mA (typ) |
| VIN (Pin 14) | Main power input | Bypassed with ≥0.22µF ceramic capacitor; supplies INTVCC and internal circuitry; max rating 40V |
| SENSE (Pin 15) | Low-side switch current sense | Kelvin-connected to source of external N-MOSFET; monitors peak switch current; clamped at 108mV (typ) for overcurrent protection |
| GATE (Pin 16) | N-MOSFET gate driver output | Swings between GND and INTVCC (7.15V); drives external FET gate; disabled during shutdown/fault |
| Exposed Pad (Pin 17) | Thermal & electrical ground | Mandatory solder connection to PCB ground plane; serves as current-sense return path and primary thermal conduction path |
Key Features
| Feature | Design Value |
|---|---|
| AEC-Q100 qualified H-grade | Rated for –40°C to +150°C junction operation - validated for automotive under-hood deployment with zero derating up to 125°C |
| High-side current sensing | Enables flexible topology selection (boost/buck/buck-boost/SEPIC/flyback) without compromising ground-referenced LED cathode or anode placement |
| Integrated OPENLED status pin | Dedicated open-collector output (Pin 9) asserts low on LED string open-circuit - eliminates need for external comparator or microcontroller monitoring |
| Programmable undervoltage lockout | SHDN/UVLO pin supports externally adjustable hysteresis via resistor divider - ensures clean start-up and brown-out recovery in noisy automotive systems |
| 100mV precision current sense threshold | Minimizes power loss in sense resistor (e.g., 10mΩ yields 10A LED current at 100mV drop) while maintaining ±3% regulation accuracy over temp |
| 3000:1 true-color PWM dimming | Preserves LED spectral output across full dimming range by avoiding low-frequency flicker and maintaining constant current amplitude during PWM on-time |
Applications
| Automotive LED Headlamps | Industrial High-Bay Lighting |
|---|---|
|
Use Scenario: 50W white LED headlamp module operating from 9–16V vehicle battery with dynamic load-dump and cold-crank immunity. IC Role / Device Role / Timing Role: Constant-current controller regulating 1.5A through 12-series white LEDs in boost topology; manages thermal foldback via CTRL pin and reports open-circuit faults via OPENLED pin. Use Value: Enables AEC-Q100-compliant, single-chip solution with integrated fault reporting - eliminates external monitoring ICs and reduces BOM count by 3–5 components. |
Use Scenario: 100W high-bay LED fixture for warehouse lighting requiring 0–10V analog dimming and surge immunity per IEC 61000-4-5. IC Role / Device Role / Timing Role: Dual-loop controller maintaining 2.5A LED current (CC) until output reaches 40V, then transitions to CV mode; uses FB pin for overvoltage clamp and SS pin for inrush limiting. Use Value: Eliminates need for separate CC/CV controllers or external op-amps - simplifies design while meeting Class II isolation and SELV compliance requirements. |
| UV-C LED Disinfection Systems | Stage & Studio LED Fixtures |
|
Use Scenario: Pulsed UV-C LED array (275nm) driven at 700mA with 100Hz–1kHz burst modulation for surface disinfection cycles. IC Role / Device Role / Timing Role: High-speed current regulator using PWM input for precise burst timing; leverages 170ns minimum off-time and fast GATE rise/fall (<35ns) to support high-frequency pulsing. Use Value: Delivers sub-millisecond current turn-on/turn-off control - critical for dose-accurate UV exposure without LED thermal runaway. |
Use Scenario: RGBW theatrical fixture requiring flicker-free dimming across 4 independent channels with synchronized PWM timing. IC Role / Device Role / Timing Role: Four-channel controller (one per color) using CTRL pin for analog fine-tuning and PWM for coarse dimming; shared SYNC signal not applicable (LT3755-2 lacks SYNC). Use Value: Achieves <0.1% RMS flicker via true-color PWM - meets EBU R128 and SMPTE ST 2067-20 standards for broadcast-grade lighting. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3783 | Single-ended flyback/buck-boost controller with integrated gate driver; no high-side current sense; 4.5V–36V input; 100kHz–1MHz freq; 1.25V FB reference | Lacks OPENLED pin and AEC-Q100 qualification; supports only flyback/buck-boost - not suitable for boost-only headlamp designs | Select LTC3783 only for isolated AC/DC-fed LED systems where galvanic isolation is mandatory and automotive qualification is not required. |
| LM3410XMY/NOPB | Monolithic 1.6MHz boost LED driver; integrated 2A MOSFET; 2.7V–5.5V input; 0.2V current sense; no high-side sensing; no OPENLED or CTRL pin | Lower voltage/current capability; no thermal grade option above 125°C; limited to low-power portable lighting | Choose LM3410XMY/NOPB for space-constrained, low-cost consumer LED flashlights - not viable for 40V-input or 150°C ambient applications. |
Compared with LTC3783 and LM3410XMY/NOPB, the LT3755HMSE-2#TRPBF uniquely combines AEC-Q100 H-grade operation, high-side current sensing for topology flexibility, dedicated OPENLED fault reporting, and dual-loop CC/CV regulation - making it the only option qualified for automotive front-lighting and high-reliability industrial LED systems.
Availability
LT3755HMSE-2#TRPBF is available at Aetrix Electronics and suitable for automotive LED headlamps, industrial high-bay lighting, and UV-C disinfection systems requiring stable component supply, extended temperature operation, and long-term lifecycle continuity.
Supply support for LT3755HMSE-2#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, 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 was designed specifically for high-power LED lighting applications demanding robust fault protection, wide input range, and automotive-grade reliability - with the LT3755-2 variant adding enhanced OPENLED functionality for safety-critical implementations.
FAQ
What is the maximum operating junction temperature for the LT3755HMSE-2#TRPBF?
The LT3755HMSE-2#TRPBF is rated for a maximum junction temperature of +150°C and is qualified to AEC-Q100 Grade H. This specification is guaranteed across the full –40°C to +150°C operating range, with thermal derating applied above 125°C per Analog Devices' reliability guidelines. The exposed pad must be soldered to a thermal pad on the PCB to achieve θJA = 43°C/W and maintain safe operation at full load.
Does the LT3755HMSE-2#TRPBF support both constant-current and constant-voltage regulation?
Yes, the LT3755HMSE-2#TRPBF supports dual-loop regulation: constant-current via ISP/ISN differential sensing (targeting 100mV) and constant-voltage via FB pin (regulated to 1.25V). The two loops interact - the current loop dominates during normal LED operation, while the voltage loop activates during open-circuit conditions or overvoltage events. FB can be grounded to disable CV mode entirely.
How does the OPENLED pin function on the LT3755HMSE-2#TRPBF?
The OPENLED pin on the LT3755HMSE-2#TRPBF is an open-drain output that pulls low when the FB voltage falls below 1.20V (1.25V – 50mV), indicating an open LED string. It remains latched during PWM low periods and updates on the next PWM high transition. An external pull-up resistor (<1mA) is required. This feature is exclusive to LT3755-2 variants and is not present on LT3755 or LT3755-1.
Can the LT3755HMSE-2#TRPBF drive a buck topology for LED current regulation?
Yes, the LT3755HMSE-2#TRPBF supports buck topology by connecting the LED string between VIN and the switch node, with ISP/ISN sensing the high-side current. Its high-side current sense architecture and wide 4.5V–40V input range make it suitable for buck configurations down to ~2V output - commonly used in automotive daytime running lights (DRLs) where VIN exceeds LED forward voltage.
What is the purpose of the CTRL pin on the LT3755HMSE-2#TRPBF?
The CTRL pin on the LT3755HMSE-2#TRPBF adjusts the ISP–ISN current sense threshold from 0mV to 100mV linearly over 0–1V, enabling analog dimming and thermal foldback. At VCTRL > 1.2V, the threshold clamps at 100mV for full-scale current. This pin allows precise LED current scaling without changing the sense resistor, supporting closed-loop thermal management using an NTC thermistor network referenced to VREF.
LT3755HMSE-2#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TFSOP (0.118", 3.00mm Width) 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):
- 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#TRPBF FAQ
1.How can I place an order for LT3755HMSE-2#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3755HMSE-2#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 LT3755HMSE-2#TRPBF reliable?
The price and inventory of LT3755HMSE-2#TRPBF 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#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3755HMSE-2#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3755HMSE-2#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3755HMSE-2#TRPBF?
LT3755HMSE-2#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3755HMSE-2#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 LT3755HMSE-2#TRPBF?
For technical support, including LT3755HMSE-2#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3755HMSE-2#TRPBF requirements.
6.How does Aetrix verify that LT3755HMSE-2#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3755HMSE-2#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 LT3755HMSE-2#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3755HMSE-2#TRPBF?
All LT3755HMSE-2#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3755HMSE-2#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 LT3755HMSE-2#TRPBF part is unused and in its original packaging.
Return procedure for LT3755HMSE-2#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3755HMSE-2#TRPBF Tags
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