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Analog Devices Inc. LT3755IMSE-2#TRPBF
- Part No.:
- LT3755IMSE-2#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3755IMSE-2#TRPBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,390
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Product details
Overview
LT3755IMSE-2#TRPBF from Analog Devices is a constant-frequency, current-mode DC/DC LED controller optimized for high-brightness LED drivers in automotive headlamps and industrial lighting. It drives an external N-channel MOSFET, supports 4.5V–40V input, delivers up to 75V output, provides 100mV high-side current sensing, and enables 3000:1 PWM dimming. Its key role is precision constant-current regulation for boost/buck/buck-boost LED topologies.
For engineers reviewing the LT3755IMSE-2#TRPBF datasheet, LT3755IMSE-2#TRPBF pinout, LT3755IMSE-2#TRPBF application, or LT3755IMSE-2#TRPBF equivalent, this page delivers verified technical context, validated pin functions, confirmed AEC-Q100 qualification, real-world dimming performance data, and manufacturer-confirmed alternative options - all specific to the LT3755IMSE-2 variant in MSOP package.
Technical Context
The LT3755IMSE-2#TRPBF implements fixed-frequency current-mode control with internal 7.15V INTVCC regulator, ground-referenced FB pin for CV/CC dual-loop operation, and dedicated high-side ISP/ISN current sense inputs enabling topology flexibility. Its oscillator frequency is programmable from 100kHz to 1MHz via RT resistor.
It features improved open-LED status reporting via OPENLED pin (active-low open-collector), programmable undervoltage lockout with hysteresis on SHDN/UVLO, and analog dimming via CTRL pin that scales the 100mV current sense threshold linearly below 1V. The device operates across –40°C to +125°C junction temperature and is AEC-Q100 qualified.
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 transients (40V). |
| Output Voltage Capability | Up to 75V - enables driving long LED strings in high-power headlamp and signage applications. |
| Current Sense Threshold | 100mV (typical) at ISP–ISN - sets precise LED current with low power loss in sense resistor. |
| Switching Frequency Range | 100kHz to 1MHz - adjustable via RT pin to balance efficiency, EMI, and magnetic component size. |
| Dimming Ratio | 3000:1 true-color PWM dimming - maintains color consistency across full brightness range in automotive lighting. |
| Operating Temperature | –40°C to +125°C (junction) - meets AEC-Q100 Grade I requirements for under-hood automotive use. |
| Package | 16-lead MSOP - thermally enhanced surface-mount package with exposed pad for PCB heat sinking. |
Pinout & Package
LT3755IMSE-2#TRPBF is housed in a 16-lead plastic MSOP package with exposed thermal pad (Pin 17 = GND). The package measures 4.9mm × 3.0mm × 1.1mm and requires soldering of the exposed pad to the PCB ground plane for thermal and electrical integrity.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PWMOUT (Pin 1) | Buffered PWM output driver | Drives external NMOS disconnect switch; toggles low during FB overvoltage (>VFB + 60mV) to protect LEDs. |
| FB (Pin 2) | Voltage feedback input | Ground-referenced node for constant-voltage regulation or open-LED detection (threshold = VFB − 50mV). |
| ISN (Pin 3) | Negative current sense input | High-side current sense return; enables short-circuit protection when ISN < 3V and ISP−ISN > 150mV. |
| ISP (Pin 4) | Positive current sense input | High-side current sense input; bias current varies with CTRL voltage; used with ISN for LED current regulation. |
| VC (Pin 5) | Error amplifier output | Transconductance amplifier output; stabilizes loop with RC network; high-impedance during PWM low for state retention. |
| CTRL (Pin 6) | Analog dimming control | Scales current sense threshold from 0V to 1.1V; 0–1V gives linear 10× scaling (e.g., 0.5V → 50mV threshold). |
| 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; low disables switching, idles oscillator, and forces GATE/PWMOUT low; internal pull-down. |
| OPENLED (Pin 9) | Open-LED fault indicator | Open-collector output asserted when FB < VFB − 50mV; requires external pull-up <1mA; latched during PWM low. |
| SS (Pin 10) | Soft-start timing | 10µA internal pull-up to 2.5V rail; soft-start time set by external capacitor; reset by UVLO or thermal shutdown. |
| RT (Pin 11) | Frequency programming | Resistor-to-GND sets oscillator frequency (100kΩ → ~375kHz); must not be left floating. |
| SHDN/UVLO (Pin 12) | Shutdown & input monitoring | 1.22V falling threshold with programmable hysteresis; sub-µA bias above threshold; pulls down 2.1µA below threshold. |
| INTVCC (Pin 13) | Internal LDO supply | 7.15V regulated output powers gate driver and logic; requires 4.7µF ceramic bypass close to pin. |
| VIN (Pin 14) | Main input supply | 4.5V–40V input; must be bypassed with ≥0.22µF ceramic capacitor near IC; powers INTVCC LDO. |
| SENSE (Pin 15) | Low-side current sense | Kelvin-connected to high-side of RSENSE; monitors switch current for slope-compensated current-mode control. |
| GATE (Pin 16) | MOSFET gate driver | Drives external N-channel FET gate between INTVCC and GND; fast rise/fall (<35ns) into 3300pF load. |
| Exposed Pad (Pin 17) | Thermal & electrical ground | Must be soldered to PCB ground plane; serves as primary thermal path and current sense return for SENSE. |
Key Features
| Feature | Design Value |
|---|---|
| High-side current sensing | Enables flexible boost, buck, buck-boost, SEPIC, and flyback topologies without ground disruption in LED string. |
| Improved OPENLED status pin | LT3755-2-specific open-collector output with re-assertion logic after overvoltage clears - enhances fault diagnostics in automotive systems. |
| AEC-Q100 qualification | Qualified to Grade I (–40°C to +125°C) for automotive lighting - ensures reliability in harsh under-hood environments. |
| 100mV current sense threshold | Minimizes power loss in sense resistor while maintaining accuracy across temperature and line/load variations. |
| Programmable 100kHz–1MHz switching | Allows optimization of magnetics size, efficiency, and EMI filtering for each application's physical and thermal constraints. |
| 3000:1 true-color PWM dimming | Preserves LED chromaticity across full dimming range - critical for adaptive front-lighting systems (AFS) and DLP illumination. |
Applications
| Automotive LED Headlamps | Industrial High-Bay Lighting |
|---|---|
|
Use Scenario: Driving 50W white LED arrays in adaptive front-lighting systems (AFS) with dynamic beam shaping. IC Role / Device Role / Timing Role: Constant-current controller regulating LED string current with synchronized PWM dimming and open-LED fault reporting. Use Value: Enables 3000:1 dimming without color shift, meets AEC-Q100 reliability, and provides fail-safe OPENLED indication for functional safety compliance (ISO 26262 ASIL-B). |
Use Scenario: Powering multi-string 100–200W LED fixtures in warehouse and factory environments with 24V/48V DC distribution. IC Role / Device Role / Timing Role: High-efficiency boost-mode LED driver with programmable frequency and thermal foldback for continuous operation. Use Value: Delivers >92% efficiency across 8–40V input range, supports remote analog dimming via 0–10V interface using CTRL pin, and includes open-LED protection for maintenance safety. |
| Battery-Powered Portable Lighting | UV-C LED Disinfection Systems |
|
Use Scenario: Driving high-current UV-A or white LEDs from 2-cell Li-ion (6–8.4V) or 12V lead-acid batteries in handheld inspection tools. IC Role / Device Role / Timing Role: Buck-boost LED controller supporting wide VIN range and low-quiescent shutdown (<1µA) for extended battery life. Use Value: Maintains constant LED current during battery discharge; soft-start prevents inrush; SS pin enables controlled ramp-up for sensitive optics. |
Use Scenario: Precise current regulation for pulsed UV-C LED arrays (265nm–285nm) requiring stable irradiance in medical and water treatment devices. IC Role / Device Role / Timing Role: High-accuracy current-mode controller with fast transient response and short-circuit protection for fragile UV-C diodes. Use Value: 100mV sense threshold enables low-loss current control; ISP/ISN common-mode range up to 75V supports series-connected UV-C strings; short-circuit detection protects expensive emitters. |
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 500kHz frequency; no RT pin; integrated gate driver with higher peak current (2A); no OPENLED pin. | Targeted at compact, fixed-frequency designs where layout simplicity outweighs programmability; lacks open-LED status reporting. | Select LTC3783EFE#PBF when board space is constrained and fixed 500kHz operation suffices; avoid if OPENLED fault signaling or frequency tuning is required. |
| LM3410XSD/NOPB | Single-stage boost-only controller; max 40V output; no high-side current sensing; 2.5V–24V input; no CTRL analog dimming. | Suitable for lower-power (<15W), cost-sensitive LED lighting with simpler topology and no need for buck/buck-boost flexibility. | Choose LM3410XSD/NOPB for entry-level portable LED drivers where topology and feature set are less demanding than LT3755IMSE-2#TRPBF. |
Compared with LTC3783EFE#PBF and LM3410XSD/NOPB, the LT3755IMSE-2#TRPBF uniquely combines AEC-Q100 qualification, programmable frequency, high-side current sensing for topology versatility, and dedicated OPENLED fault reporting - making it the only option among the three qualified for automotive headlamp systems requiring functional safety awareness.
Availability
LT3755IMSE-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, AEC-Q100 compliance, and long-term production continuity.
Supply support for LT3755IMSE-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 (DSP) technologies, serving industrial, automotive, communications, and healthcare markets.
The LT3755 family was designed specifically for high-reliability, high-power LED driver applications - emphasizing precision current regulation, topology flexibility, automotive-grade robustness, and integrated protection features like open-LED and short-circuit detection.
FAQ
What is the key difference between LT3755IMSE-2#TRPBF and the LT3755-1 variant?
The LT3755IMSE-2#TRPBF includes an improved OPENLED status pin with re-assertion logic after overvoltage events clear, whereas the LT3755-1 replaces OPENLED with a SYNC pin for oscillator synchronization. This makes LT3755IMSE-2#TRPBF ideal for automotive fault-reporting systems requiring persistent open-LED indication, while LT3755-1 suits noise-sensitive applications needing external clock alignment.
Does LT3755IMSE-2#TRPBF support buck-mode LED driving?
Yes, LT3755IMSE-2#TRPBF supports buck-mode operation using high-side current sensing - a key advantage over traditional low-side controllers. When configured in buck topology, the ISP/ISN inputs monitor LED current directly at the high side of the string, preserving ground integrity and enabling seamless integration with existing LED module designs.
What is the maximum output voltage achievable with LT3755IMSE-2#TRPBF?
The LT3755IMSE-2#TRPBF supports output voltages up to 75V, as confirmed in the Absolute Maximum Ratings and Typical Applications sections of the official datasheet. This capability enables driving long series strings of high-brightness LEDs in automotive headlamps and commercial lighting fixtures without cascading converters.
How does the CTRL pin function for analog dimming in LT3755IMSE-2#TRPBF?
In LT3755IMSE-2#TRPBF, the CTRL pin adjusts the ISP–ISN current sense threshold linearly from 0V to 1.1V: below 1V, threshold = 10 × VCTRL; above 1.2V, threshold is fixed at 100mV. This allows precise analog dimming control using a simple DAC or potentiometer, independent of PWM timing - essential for flicker-free dimming in video studio and medical lighting.
Is LT3755IMSE-2#TRPBF pin-compatible with other LT3755 variants in MSOP package?
Yes, all LT3755 variants in the 16-lead MSOP package - including LT3755IMSE#TRPBF, LT3755IMSE-1#TRPBF, and LT3755IMSE-2#TRPBF - share identical pinout and footprint. However, functionality differs per variant: LT3755IMSE-2#TRPBF uses Pin 9 as OPENLED, while LT3755IMSE-1#TRPBF uses it as SYNC. Board design must match the selected variant's functional pin assignment.
LT3755IMSE-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 ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LT3755IMSE-2#TRPBF FAQ
1.How can I place an order for LT3755IMSE-2#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3755IMSE-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 LT3755IMSE-2#TRPBF reliable?
The price and inventory of LT3755IMSE-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 LT3755IMSE-2#TRPBF is usually 5 days.
3.What payment methods are accepted for LT3755IMSE-2#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3755IMSE-2#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3755IMSE-2#TRPBF?
LT3755IMSE-2#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3755IMSE-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 LT3755IMSE-2#TRPBF?
For technical support, including LT3755IMSE-2#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3755IMSE-2#TRPBF requirements.
6.How does Aetrix verify that LT3755IMSE-2#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT3755IMSE-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 LT3755IMSE-2#TRPBF meets industry standards.
7.What is the process for return or replacement of LT3755IMSE-2#TRPBF?
All LT3755IMSE-2#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3755IMSE-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 LT3755IMSE-2#TRPBF part is unused and in its original packaging.
Return procedure for LT3755IMSE-2#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3755IMSE-2#TRPBF Tags
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