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Analog Devices Inc. LT3755EMSE-1#WTRPBF
- Part No.:
- LT3755EMSE-1#WTRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3755EMSE-1#WTRPBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,479
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Product details
Overview
LT3755EMSE-1#WTRPBF from Analog Devices is a constant-frequency, current-mode DC/DC LED controller driving external N-channel MOSFETs in boost, buck, or buck-boost topologies. It features 4.5V–40V input range, 75V max output, 100kHz–1MHz adjustable switching frequency, high-side current sensing with 100mV threshold, and AEC-Q100 qualification for automotive headlamp drivers.
For engineers reviewing the LT3755EMSE-1#WTRPBF datasheet, LT3755EMSE-1#WTRPBF pinout, LT3755EMSE-1#WTRPBF application, or LT3755EMSE-1#WTRPBF equivalent, key selection criteria include its SYNC-capable oscillator (LT3755-1 variant), open-LED fault reporting via OPENLED pin, PWM dimming up to 3000:1, and thermally enhanced 16-lead MSOP package with exposed pad.
Technical Context
The LT3755EMSE-1#WTRPBF implements fixed-frequency current-mode control with internal 7.15V INTVCC regulator powering gate driver and logic. Its dual-loop architecture supports simultaneous constant-current (via ISP/ISN) and constant-voltage (via FB) regulation, with VC pin serving as transconductance error amplifier output for loop compensation.
As the -1 variant, it replaces the OPENLED function with SYNC input for external clock synchronization-enabling precise timing coordination in multi-phase or noise-sensitive systems. The CTRL pin provides analog dimming by scaling the 100mV current sense threshold linearly below 1V, while PWM input enables true-color PWM dimming with dedicated PWMOUT buffer for NMOS disconnect switches.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 40V - supports wide automotive battery range including cold-crank and load-dump conditions. |
| Max Output Voltage | 75V - enables driving long LED strings in high-brightness automotive lighting. |
| Switching Frequency | 100kHz to 1MHz - programmable via RT resistor to optimize EMI, efficiency, or inductor size. |
| Current Sense Threshold | 100mV (typical) - low-loss, high-accuracy high-side sensing with 98–118mV min/max over temp. |
| CTRL Pin Dimming Range | 0V to 1.1V - enables analog current scaling from ~0% to 100% of full-scale LED current. |
| SYNC Input Compatibility | Logic-level sync input (1.5V high, 0.4V low) - allows external clock locking for EMI reduction or multi-controller coherence. |
| Shutdown Current | <1µA - ultra-low quiescent draw during vehicle sleep mode to preserve battery. |
Pinout & Package
LT3755EMSE-1#WTRPBF uses a thermally enhanced 16-lead plastic MSOP package (3mm × 4.9mm) with exposed pad soldered to PCB ground for thermal dissipation and current sense reference. Pin 17 (exposed pad) is GND and mandatory for thermal and electrical performance.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PWMOUT (Pin 1) | Buffered PWM output | Drives external NMOS disconnect switch; toggles low on FB overvoltage (>VFB + 60mV) to protect LEDs. |
| FB (Pin 2) | Voltage feedback input | Regulates output voltage to 1.25V reference; triggers OPENLED pull-down if < VFB – 50mV (not active on -1 variant). |
| ISN (Pin 3) | Negative current sense input | High-side current sense return; enables short-circuit detection 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 per datasheet curves. |
| VC (Pin 5) | Error amplifier output | Integrates difference between ISP–ISN and CTRL-set threshold; high-impedance during PWM low for state retention. |
| CTRL (Pin 6) | Analog dimming control | Scales current sense threshold from 0mV to 100mV linearly (0–1V), then holds at full scale (>1.2V). |
| VREF (Pin 7) | 2.0V reference output | Stable 2.0V source (±2%) for CTRL divider or temperature compensation networks; supplies ≤100µA. |
| PWM (Pin 8) | Digital dimming input | Active-high enable; shuts down oscillator, drives GATE/PWMOUT low, and places VC in high-Z storage mode. |
| SYNC (Pin 9) | External clock input | Replaces OPENLED on LT3755-1; synchronizes internal oscillator to external 100kHz–1MHz logic signal. |
| SS (Pin 10) | Soft-start capacitor | 10µA internal pull-up to 2.5V rail; sets startup ramp time and prevents inrush; reset by UVLO or thermal fault. |
| RT (Pin 11) | Frequency programming | Resistor-to-GND sets oscillator frequency; 10kΩ = ~1MHz, 100kΩ = ~100kHz per typical curve. |
| SHDN/UVLO (Pin 12) | Enable & undervoltage detect | 1.22V falling threshold with programmable hysteresis; pulls 2.1µA below threshold to set hysteresis with external divider. |
| INTVCC (Pin 13) | Internal 7.15V regulator | Supplies gate driver and logic; requires 4.7µF local ceramic bypass; drops out at ~350mV under 10mA load. |
| VIN (Pin 14) | Main power input | 4.5V–40V supply; must be bypassed with ≥0.22µF ceramic capacitor close to pin. |
| 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 | Drives external N-channel MOSFET gate between INTVCC and GND; rise/fall time <35ns into 3.3nF. |
Key Features
| Feature | Design Value |
|---|---|
| SYNC input for oscillator locking | Enables deterministic timing across multiple controllers or against system clocks to reduce beat frequencies and EMI peaks. |
| High-side current sensing (ISP/ISN) | Supports all topologies (boost/buck/buck-boost/SEPIC/flyback) without ground path disruption or shunt resistor heating issues. |
| True-color PWM dimming (3000:1) | Preserves LED chromaticity across full dimming range using clean, jitter-free PWMOUT-driven disconnect switch. |
| AEC-Q100 qualified (Grade E) | Validated for automotive ambient temperatures (–40°C to +125°C junction), vibration, and lifetime reliability per automotive standards. |
| Programmable soft-start (SS pin) | Prevents inrush current and output overshoot via user-defined RC time constant; resets automatically on UVLO or thermal fault. |
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 while synchronizing switching to vehicle CAN clock via SYNC pin. Use Value: Enables EMI-compliant 500kHz operation locked to system clock, eliminating heterodyne noise in camera-based vision systems. | Use Scenario: Powering 100–200W LED fixtures in warehouse ceilings with 0–10V analog dimming interface. IC Role / Device Role / Timing Role: Dual-loop controller maintaining precise current regulation while accepting 0–10V analog command on CTRL pin for smooth dimming. Use Value: Delivers ±2% current accuracy over line/load/temp, eliminating visible flicker and color shift in large-area illumination. |
| Battery-Powered Emergency Lighting | UV-C LED Disinfection Systems |
Use Scenario: Self-contained emergency exit sign with Li-ion backup, requiring ultra-low shutdown IQ and wide VIN range. IC Role / Device Role / Timing Role: LED driver with <1µA shutdown current and 4.5V start-up capability, enabling operation down to single-cell Li-ion voltage. Use Value: Extends battery runtime by >30% versus comparable controllers, meeting UL 924 90-minute runtime requirements. | Use Scenario: Pulsed UV-C LED arrays for surface sterilization, demanding precise current pulse control and thermal derating. IC Role / Device Role / Timing Role: Fast-response current controller with programmable soft-start and thermal foldback via VC loop interaction. Use Value: Maintains ±1% pulse-to-pulse current stability across 100–1000Hz burst modes, ensuring consistent germicidal dose delivery. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT3755EMSE#WTRPBF | No SYNC pin; OPENLED status output instead; identical pinout and topology support. | Preferred where open-LED fault reporting is required and clock synchronization is unnecessary. | Select when system diagnostics prioritize fault visibility over timing coordination. |
| LT3755EMSE-2#WTRPBF | Includes enhanced OPENLED latching behavior and improved short-circuit detection; no SYNC. | Optimized for safety-critical lighting where reliable open-load detection and fast fault response are mandatory. | Choose for ASIL-B–aligned designs requiring robust fault handling without external supervision. |
Compared with LT3755EMSE#WTRPBF and LT3755EMSE-2#WTRPBF, the LT3755EMSE-1#WTRPBF trades open-LED reporting for external clock synchronization-making it optimal for EMI-sensitive multi-controller systems where deterministic timing outweighs standalone fault signaling.
Availability
LT3755EMSE-1#WTRPBF is available at Aetrix Electronics and suitable for automotive LED headlamps, industrial high-bay lighting, and battery-powered emergency signage requiring stable component supply, AEC-Q100 compliance, and production-ready thermal packaging.
Supply support for LT3755EMSE-1#WTRPBF 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 LT3755 product line delivers high-efficiency, high-reliability LED controllers optimized for automotive-grade lighting systems, featuring integrated protection, flexible topology support, and AEC-Q100 qualification across temperature grades.
FAQ
What is the primary function of the SYNC pin on the LT3755EMSE-1#WTRPBF?
The SYNC pin on the LT3755EMSE-1#WTRPBF replaces the OPENLED function found on non–1 variants and accepts an external logic-level clock signal (100kHz–1MHz) to synchronize the internal oscillator. This ensures deterministic switching timing across multiple LT3755EMSE-1#WTRPBF controllers or aligns switching edges with system clocks-reducing beat frequencies and EMI peaks. The LT3755EMSE-1#WTRPBF requires the internal frequency to be set ~20% lower than the SYNC signal using the RT resistor.
How does the LT3755EMSE-1#WTRPBF support both constant-current and constant-voltage regulation?
The LT3755EMSE-1#WTRPBF supports dual-loop regulation through independent feedback paths: high-side current sensing (ISP/ISN) for constant-current mode and FB pin monitoring for constant-voltage mode. The VC error amplifier integrates both loops, prioritizing current regulation unless FB exceeds its 1.25V reference-then voltage regulation dominates. This enables safe operation during open-LED faults and seamless transition between modes in hybrid LED+capacitor hold-up designs.
What is the maximum output voltage capability of the LT3755EMSE-1#WTRPBF?
The LT3755EMSE-1#WTRPBF supports output voltages up to 75V, as confirmed by Absolute Maximum Ratings (ISP/ISN pins rated to 75V) and Typical Application circuits demonstrating 50W LED string operation at elevated bus voltages. This rating applies regardless of topology-boost, buck, buck-boost, SEPIC, or flyback-and is sustained under full thermal and load conditions within the –40°C to +125°C operating junction temperature range.
Can the LT3755EMSE-1#WTRPBF drive LEDs in buck configuration?
Yes, the LT3755EMSE-1#WTRPBF explicitly supports buck-mode LED driving, as stated in the FEATURES section ("Drives LEDs in Boost, Buck Mode, Buck-Boost Mode, SEPIC or Flyback Topology") and validated in application schematics. In buck configuration, the high-side current sense (ISP/ISN) monitors LED current directly, while the GATE driver controls the low-side N-channel MOSFET. The controller maintains stable current regulation independent of input/output voltage relationship.
What thermal package options are available for the LT3755EMSE-1#WTRPBF?
The LT3755EMSE-1#WTRPBF is offered exclusively in the 16-lead plastic MSOP package with exposed pad (θJA = 43°C/W), rated for –40°C to +125°C junction temperature. The exposed pad (Pin 17) must be soldered to the PCB ground plane for thermal conduction and electrical reference. No QFN or other package variants exist for the EMSE-1 grade; the "E" prefix denotes the industrial/automotive temperature grade, and "W" suffix confirms AEC-Q100 automotive qualification.
LT3755EMSE-1#WTRPBF 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:
- General Purpose
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LT3755EMSE-1#WTRPBF FAQ
1.How can I place an order for LT3755EMSE-1#WTRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3755EMSE-1#WTRPBF 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 LT3755EMSE-1#WTRPBF reliable?
The price and inventory of LT3755EMSE-1#WTRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3755EMSE-1#WTRPBF is usually 5 days.
3.What payment methods are accepted for LT3755EMSE-1#WTRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3755EMSE-1#WTRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3755EMSE-1#WTRPBF?
LT3755EMSE-1#WTRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3755EMSE-1#WTRPBF 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 LT3755EMSE-1#WTRPBF?
For technical support, including LT3755EMSE-1#WTRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3755EMSE-1#WTRPBF requirements.
6.How does Aetrix verify that LT3755EMSE-1#WTRPBF is sourced from the original manufacturer or authorized distributors?
All LT3755EMSE-1#WTRPBF 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 LT3755EMSE-1#WTRPBF meets industry standards.
7.What is the process for return or replacement of LT3755EMSE-1#WTRPBF?
All LT3755EMSE-1#WTRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3755EMSE-1#WTRPBF, 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 LT3755EMSE-1#WTRPBF part is unused and in its original packaging.
Return procedure for LT3755EMSE-1#WTRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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