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Analog Devices Inc. LT3761AEMSE#WTRPBF
- Part No.:
- LT3761AEMSE#WTRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3761AEMSE#WTRPBF.pdf
- Description:
- IC LED DRV DC DC CTRL PWM 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,153
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Product details
Overview
LT3761AEMSE#WTRPBF from Analog Devices is a 4.5V–60V input, constant-current/constant-voltage DC/DC controller optimized for high-current LED driving in boost, SEPIC, buck-boost, and flyback topologies. It delivers ±3% current regulation accuracy, supports 100kHz–1MHz programmable switching frequency, and integrates an internal PWM dimming generator with 4%–96% duty control. Used in automotive headlamps requiring 25:1 internal PWM dimming and open-LED fault reporting.
For engineers reviewing the LT3761AEMSE#WTRPBF datasheet, LT3761AEMSE#WTRPBF pinout, LT3761AEMSE#WTRPBF application, or LT3761AEMSE#WTRPBF equivalent, this page provides verified technical context, validated pin functions, confirmed AEC-Q100 qualification, real-world dimming performance data (3000:1 external PWM), and precise package mapping to the thermally enhanced 16-lead MSOP with exposed GND pad.
Technical Context
The LT3761AEMSE#WTRPBF implements fixed-frequency current-mode control with rail-to-rail high-side or low-side current sensing (0V–80V ISP/ISN common-mode range) and dual-loop regulation: VC error amplifier governs peak switch current via SENSE feedback, while FB loop regulates output voltage at 1.25V reference. Its internal PWM generator uses DIM/SS pin current to set PWMOUT duty ratio (3.2%–97%) and frequency (215Hz–400Hz) via external capacitor.
Protection architecture includes open-LED detection (FB < VFB – 50mV + ISP/ISN < 25mV), FB overvoltage shutdown (FB > VFB + 60mV), ISP/ISN overcurrent latch (ISP–ISN > 600mV), and thermal shutdown (>165°C). The IC operates across –40°C to 125°C ambient, with INTVCC LDO regulated at 7.85V (±0.2V) and <1µA shutdown IQ.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 4.5V to 60V - supports 12V/24V/48V automotive and industrial rails without pre-regulation |
| Current Regulation Accuracy | ±3% - enables stable LED brightness control across temperature and line variations |
| Switching Frequency Range | 100kHz to 1MHz - adjustable via RT resistor to balance efficiency, EMI, and magnetics size |
| PWM Dimming Ratio | 3000:1 (external) / 25:1 (internal) - preserves LED color fidelity during deep dimming |
| SENSE Threshold | 105mV (typ) - sets current limit with minimal power loss in sense resistor |
| Operating Temperature | –40°C to 125°C - qualified per AEC-Q100 Grade 1 for under-hood automotive use |
| Package | 16-Lead MSOP with exposed GND pad - θJC = 4°C/W enables high-power dissipation in compact layout |
Pinout & Package
LT3761AEMSE#WTRPBF is housed in a thermally enhanced 16-lead plastic MSOP (MSE) package with exposed GND pad (Pin 17), requiring soldering to PCB ground plane for thermal and electrical integrity (θJA = 43°C/W, θJC = 4°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PWMOUT (1) | Buffered PWM output | Drives NMOS disconnect FET; toggles low on FB overvoltage (>VFB + 60mV) for LED protection |
| FB (2) | Voltage feedback input | Sets CV regulation point at 1.25V; triggers OPENLED when < VFB – 50mV + ISP/ISN < 25mV |
| ISN (3) | Negative current sense input | Completes high-side or low-side current sense path; bias current varies with CTRL voltage |
| ISP (4) | Positive current sense input | Accepts 0V–80V common-mode voltage; detects overcurrent if ISP–ISN > 600mV |
| VC (5) | Error amplifier output | Integrates demand current state; high-impedance during PWM low to retain compensation charge |
| CTRL (6) | Current threshold adjust | Linearly scales VISP–ISN from 21mV to 250mV (0–1V); clamped at full scale above 1.2V |
| VREF (7) | 2.02V reference output | Supplies up to 185µA for CTRL divider or thermal compensation networks |
| PWM (8) | Digital dimming input | Enables external PWM dimming or self-oscillates with CPWM to GND for internal dimming |
| OPENLED (9) | Open-load status flag | Open-drain output pulled low when FB drops below threshold and current sense falls below C/10 |
| DIM/SS (10) | Soft-start & PWM gen control | 14µA internal pull-up sets PWMOUT duty/frequency; resets on UVLO or overcurrent |
| RT (11) | Frequency programming | Resistor to GND selects switching frequency from 100kHz (95.3kΩ) to 1MHz (8.87kΩ) |
| EN/UVLO (12) | Enable & undervoltage lockout | 1.22V falling threshold with 20mV hysteresis; 2.3µA pull-down enables external hysteresis design |
| INTVCC (13) | Internal LDO output | 7.85V regulated supply for gate drivers; requires 1µF ceramic bypass close to pin |
| VIN (14) | Main power input | Bypassed with ≥0.22µF ceramic cap; powers INTVCC LDO and internal logic |
| SENSE (15) | Switch current sense | Kelvin-connected to source of external NFET; limits switch current at 105mV threshold |
| GATE (16) | NFET gate driver | Drives external power MOSFET between INTVCC and GND; low during fault/idle |
| GND (17) | Power & signal ground | Exposed pad must be soldered to PCB ground plane for thermal conduction and current sense return |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail current sense input range | 0V to 80V on ISP/ISN - enables grounded-anode LED strings and high-voltage battery charging |
| Programmable internal PWM generator | Duty ratio 4%–96% and frequency 215Hz–400Hz set by DIM/SS current and CPWM value |
| True Color PWM™ dimming | 3000:1 external ratio with no color shift - achieved via precise timing control and fast gate drive (25ns rise/fall) |
| Output short-circuit protected boost | ISP/ISN > 600mV triggers immediate GATE/PWMOUT shutdown and 4µs fault hold-off |
| AEC-Q100 automotive qualification | Grade 1 (–40°C to 125°C) with controlled manufacturing - certified for safety-critical lighting systems |
| C/10 indication for battery chargers | 25mV ISP/ISN threshold asserts OPENLED at end-of-charge - eliminates need for external coulomb counter |
Applications
| Automotive Headlamps | High-Voltage LED Strings |
|---|---|
Use Scenario: Adaptive front-lighting systems requiring precise 0–100% brightness control and thermal derating. IC Role / Device Role / Timing Role: Constant-current LED driver in boost configuration with analog + PWM dimming and open-LED fault reporting. Use Value: 94% efficiency at 350kHz enables compact heatsink-free design; AEC-Q100 qualification ensures reliability in under-hood environments. |
Use Scenario: Architectural lighting using >100V LED strings powered from 48V DC distribution bus. IC Role / Device Role / Timing Role: High-side current-sense boost controller with rail-to-rail ISP/ISN inputs referenced to system ground. Use Value: 80V ISP/ISN common-mode range allows direct sensing without level-shifting; ±3% current accuracy maintains uniform luminance across long strings. |
| Battery & Supercapacitor Chargers | Accurate Current-Limited Voltage Regulators |
Use Scenario: 12V–48V Li-ion or supercap charger with CC/CV profile and end-of-charge C/10 detection. IC Role / Device Role / Timing Role: Constant-current source transitioning to constant-voltage regulator with OPENLED used as charge-complete flag. Use Value: Integrated C/10 threshold (25mV) eliminates external comparator; ±2% voltage regulation ensures safe battery termination. |
Use Scenario: Industrial test equipment requiring stable, current-limited 5V/12V/24V outputs with fast transient response. IC Role / Device Role / Timing Role: Dual-loop regulator using FB for voltage control and ISP/ISN for foldback current limiting. Use Value: Simultaneous CC/CV operation prevents output overload; 100kHz–1MHz frequency tuning optimizes response time vs. filter size. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LTC3789EMSE#PBF | 4-phase synchronous buck-boost controller; no integrated PWM generator; requires external dimming circuitry | Targeted at high-power multi-string LED arrays with phase interleaving; lacks open-LED reporting | Select when >100W output and interleaved ripple reduction are required; not drop-in for LT3761AEMSE#WTRPBF's single-switch topologies |
| LM3410XSD/NOPB | 600kHz fixed-frequency boost controller; no internal PWM generator; only 1.5A max switch current; no AEC-Q100 rating | Cost-sensitive consumer LED lighting; limited to <20W output; unsuitable for automotive or battery charging | Choose for non-automotive, low-power boost LED drivers where internal dimming and fault reporting are unnecessary |
Compared with LTC3789EMSE#PBF and LM3410XSD/NOPB, the LT3761AEMSE#WTRPBF uniquely combines AEC-Q100 qualification, integrated PWM dimming, open-LED reporting, and 0–80V current sense range-making it the only option qualified for automotive headlamp and high-voltage battery charger designs requiring single-chip simplicity and safety compliance.
Availability
LT3761AEMSE#WTRPBF is available at Aetrix Electronics and suitable for automotive lighting, high-voltage LED signage, battery charging systems, and industrial current-limited power supplies requiring stable component supply and AEC-Q100 traceability.
Supply support for LT3761AEMSE#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 industrial, automotive, communications, and healthcare markets.
The LT3761A product line delivers highly integrated, AEC-Q100-qualified LED controllers with dual-loop regulation and robust protection-designed specifically for automotive headlamps, high-voltage LED systems, and precision battery charging applications.
FAQ
What is the key difference between LT3761AEMSE#WTRPBF and the standard LT3761AEMSE#TRPBF?
The LT3761AEMSE#WTRPBF is the automotive-grade variant with controlled manufacturing per AEC-Q100 Grade 1 requirements (–40°C to 125°C), including enhanced reliability testing and traceable lot documentation. The LT3761AEMSE#TRPBF is the commercial-grade version without automotive qualification or extended reliability validation. Both share identical electrical specifications and pinout, but only the #W suffix parts are approved for automotive safety-critical lighting systems.
How does the internal PWM dimming generator in LT3761AEMSE#WTRPBF achieve 25:1 dimming ratio?
The LT3761AEMSE#WTRPBF achieves 25:1 internal PWM dimming by using the DIM/SS pin current to program both duty cycle (4%–96%) and frequency (215Hz–400Hz) of the PWMOUT signal. With a 47nF capacitor on the PWM pin and DIM/SS current set to 0µA, the device delivers ~50% duty at ~300Hz; adjusting DIM/SS current shifts duty linearly while maintaining stable frequency, enabling precise analog-like brightness control without external microcontroller intervention.
Can LT3761AEMSE#WTRPBF operate in buck mode, and what are the layout considerations?
Yes, LT3761AEMSE#WTRPBF supports buck mode operation using low-side current sensing. Layout requires Kelvin connection of SENSE to the source of the external NFET and ISN to GND, with ISP tied to the switch node. The GATE driver must drive an NFET configured as low-side switch, and the FB network must be referenced to output ground. Critical paths-SENSE, ISP/ISN, and GND pad-must minimize parasitic inductance to maintain current sense accuracy and stability.
What protection features does LT3761AEMSE#WTRPBF provide for LED string open-circuit conditions?
The LT3761AEMSE#WTRPBF detects open-LED faults by monitoring two simultaneous conditions: FB voltage dropping below VFB – 50mV (1.205V typical) AND ISP/ISN differential falling below the C/10 threshold of 25mV. When both occur, the OPENLED pin pulls low (open-drain) to signal fault condition. This dual-criteria method prevents false triggering during transient voltage dips or current surges, ensuring reliable status reporting in automotive headlamp systems.
Is the exposed pad (Pin 17) of LT3761AEMSE#WTRPBF electrically connected to GND, and must it be soldered?
Yes, the exposed pad (Pin 17) of LT3761AEMSE#WTRPBF is internally connected to GND and serves as both the primary thermal path and the current sense return for the SENSE and ISN pins. It must be soldered directly to a large PCB copper pour tied to system GND. Failure to solder the pad results in excessive junction temperature (>165°C thermal shutdown), degraded current sense accuracy due to ground bounce, and potential instability in the control loop.
LT3761AEMSE#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):
- Yes
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 4.5V
- Voltage - Supply (Max):
- 60V
- Voltage - Output:
- -
- Current - Output / Channel:
- -
- Frequency:
- 100kHz ~ 1MHz
- Dimming:
- Analog, PWM
- Applications:
- General Purpose
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LT3761AEMSE#WTRPBF FAQ
1.How can I place an order for LT3761AEMSE#WTRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3761AEMSE#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 LT3761AEMSE#WTRPBF reliable?
The price and inventory of LT3761AEMSE#WTRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3761AEMSE#WTRPBF is usually 5 days.
3.What payment methods are accepted for LT3761AEMSE#WTRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3761AEMSE#WTRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3761AEMSE#WTRPBF?
LT3761AEMSE#WTRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3761AEMSE#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 LT3761AEMSE#WTRPBF?
For technical support, including LT3761AEMSE#WTRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3761AEMSE#WTRPBF requirements.
6.How does Aetrix verify that LT3761AEMSE#WTRPBF is sourced from the original manufacturer or authorized distributors?
All LT3761AEMSE#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 LT3761AEMSE#WTRPBF meets industry standards.
7.What is the process for return or replacement of LT3761AEMSE#WTRPBF?
All LT3761AEMSE#WTRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3761AEMSE#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 LT3761AEMSE#WTRPBF part is unused and in its original packaging.
Return procedure for LT3761AEMSE#WTRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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