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Analog Devices Inc. LT3761IMSE-1#PBF
- Part No.:
- LT3761IMSE-1#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3761IMSE-1#PBF.pdf
- Description:
- IC LED DRIVER CTRLR PWM 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:142
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Product details
Overview
LT3761IMSE-1#PBF from Analog Devices is a 4.5V–60V input, constant-frequency current-mode DC/DC LED controller with integrated PWM dimming generator and frequency synchronization capability. It regulates LED current with ±3% accuracy and output voltage with ±2% accuracy, supports high-side or low-side current sensing up to 80V common-mode, and delivers up to 94% efficiency in automotive headlamp boost configurations.
For engineers reviewing the LT3761IMSE-1#PBF datasheet, LT3761IMSE-1#PBF pinout, LT3761IMSE-1#PBF application, or LT3761IMSE-1#PBF equivalent, key selection considerations include its 100kHz–1MHz programmable switching frequency, 3000:1 True Color PWM™ dimming ratio, rail-to-rail 0V–80V ISP/ISN sensing range, and SYNC pin compatibility with external clock sources for EMI reduction.
Technical Context
The LT3761IMSE-1#PBF implements a fixed-frequency, current-mode control architecture with dual-loop regulation: the ISP/ISN differential input governs constant-current operation via a transconductance error amplifier (VC), while FB enables constant-voltage regulation at 1.25V nominal reference. Its internal PWM generator uses DIM/SS current programming to set duty cycle (4%–96%) and frequency (215Hz–435Hz) independently of main switching frequency.
Unlike the base LT3761, the -1 variant replaces OPENLED with a dedicated SYNC pin (30kΩ pull-down, 1.5V logic-high threshold), enabling precise oscillator synchronization - critical for noise-sensitive multi-phase LED systems. The GATE driver delivers fast 25ns rise/fall times into 3300pF loads, and INTVCC provides regulated 7.85V (±0.2V) supply with 36mA current limit for gate driving and internal circuitry.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Range | 4.5V to 60V - supports wide-input industrial and automotive power rails without pre-regulation. |
| ISP/ISN Common-Mode Range | 0V to 80V - enables grounded-anode LED strings and high-voltage battery charging topologies. |
| Switching Frequency | 100kHz to 1MHz - adjustable via RT resistor; allows optimization of magnetics size, efficiency, and EMI performance. |
| PWM Dimming Ratio | Up to 3000:1 - true-color dimming preserves LED chromaticity across full brightness range. |
| Current Sense Threshold Accuracy | ±3% - ensures stable LED current regulation under thermal and supply variations. |
| SYNC Input Compatibility | Logic-level sync (1.5V high / 0.4V low) - enables deterministic phase alignment with external clocks for multi-controller systems. |
| Package | 16-Lead MSOP with exposed pad - thermally enhanced for 125°C ambient operation and high-power density layouts. |
Pinout & Package
LT3761IMSE-1#PBF is housed in a thermally enhanced 16-lead plastic MSOP package (MSE) with exposed pad (Pin 17) soldered to PCB ground for thermal and electrical integrity. θJA = 43°C/W, θJC = 4°C/W, TJMAX = 125°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| PWMOUT (1) | Buffered PWM output | Drives NMOS disconnect FET or level-shifts PWM signal; toggles during FB overvoltage fault (VFB + 60mV). |
| FB (2) | Voltage feedback input | Sets constant-voltage regulation point at 1.25V; enables open-LED detection when combined with ISP/ISN <25mV. |
| ISN (3) | Negative current sense input | Completes high-side or low-side current sense path; bias current varies with CTRL voltage and ISP/ISN differential. |
| ISP (4) | Positive current sense input | Accepts up to 80V common-mode; triggers overcurrent shutdown if ISP–ISN >600mV (typical). |
| VC (5) | Error amplifier output | High-impedance node storing demand current state; requires RC compensation network for loop stability. |
| CTRL (6) | Current threshold adjust | Linearly scales VISP-ISN from 21mV to 258mV (0–1.0V range); clamps at full-scale 250mV above 1.2V. |
| VREF (7) | 2.02V reference output | Supplies up to 185µA; used to bias CTRL divider for analog dimming or temperature compensation. |
| PWM (8) | Digital dimming input | Enables external PWM dimming or self-oscillates with capacitor; supports hiccup-mode short-circuit protection. |
| SYNC (9) | External clock input | Replaces OPENLED on -1 variant; synchronizes internal oscillator with external 50% duty-cycle logic signal. |
| DIM/SS (10) | Soft-start & PWM gen control | 12µA internal pull-up sets PWMOUT duty/frequency; capacitor value determines soft-start time and dimming waveform. |
| RT (11) | Frequency programming | Resistor to GND sets switching frequency from 100kHz to 1MHz per published curve. |
| EN/UVLO (12) | Enable & undervoltage lockout | 1.22V falling threshold with 20mV hysteresis; 2.3µA pull-down enables precise UVLO hysteresis design. |
| INTVCC (13) | Internal LDO output | 7.85V regulated supply for gate drivers and internal circuits; requires 1µF ceramic bypass to exposed pad. |
| VIN (14) | Main power input | Supplies INTVCC LDO; must be bypassed with ≥0.22µF low-ESR capacitor near pin and exposed pad. |
| SENSE (15) | Switch current sense | Kelvin-connected to source of external NFET; monitors switch current with 105mV (typ) current-limit threshold. |
| GATE (16) | NFET gate driver | Drives external power MOSFET between INTVCC and GND; 25ns rise/fall into 3300pF load. |
| GND (17) | Power & signal ground | Exposed pad serves as primary thermal path and current sense return; must be soldered to PCB ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| True Color PWM™ dimming | 3000:1 ratio preserves LED color fidelity across entire dimming range without flicker or hue shift. |
| Programmable switching frequency | 100kHz–1MHz via single RT resistor - balances efficiency, component size, and EMI compliance. |
| High-voltage current sensing | 0V–80V ISP/ISN common-mode range enables direct sensing in grounded-anode LED strings >100V. |
| Integrated SYNC functionality | Dedicated logic-level SYNC pin (Pin 9) allows deterministic phase alignment with external clocks for multi-controller systems. |
| Robust fault protection | Combined ISP/ISN overcurrent (>600mV), FB overvoltage (>VFB+60mV), and thermal shutdown protect power stage and LEDs. |
Applications
| Automotive Headlamps | Industrial High-Bay Lighting |
|---|---|
Use Scenario: Driving high-power white LED arrays in vehicle forward lighting with adaptive beam control. IC Role / Device Role / Timing Role: Constant-current LED controller with synchronized PWM dimming and overtemperature protection. Use Value: Enables 94% efficient boost topology with 25:1 internal PWM dimming and EMI-controlled switching via SYNC pin. | Use Scenario: Powering 48V–72V LED strings in warehouse and factory ceiling fixtures requiring long-life reliability. IC Role / Device Role / Timing Role: High-voltage current-mode controller supporting SEPIC and buck-boost configurations. Use Value: Rail-to-rail 0V–80V ISP/ISN sensing eliminates need for isolated sense amplifiers in grounded-anode designs. |
| Battery Charging Systems | Medical Surgical Lighting |
Use Scenario: Constant-current/constant-voltage charging of Li-ion and supercapacitor banks in portable equipment. IC Role / Device Role / Timing Role: Dual-loop regulator with C/10 charge termination indication and open-cell protection. Use Value: ±3% current accuracy and ±2% voltage regulation ensure safe, repeatable charge profiles without external DACs. | Use Scenario: Precision dimmable LED illumination in operating rooms where color rendering and flicker-free operation are critical. IC Role / Device Role / Timing Role: True Color PWM™ controller with 3000:1 dimming and low-noise current regulation. Use Value: Eliminates perceptible flicker and chromaticity shift across clinical brightness levels, meeting IEC 62368-1 requirements. |
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 | No internal PWM generator; requires external dimming signal; lacks SYNC pin; 40V max VIN. | Best suited for fixed-frequency, externally dimmed LED systems where internal dimming is unnecessary. | Select when system already provides clean external PWM and VIN stays below 40V. |
| LT3965EFE#PBF | 8-channel independent LED driver with I²C interface; 60V VIN; no SYNC; integrated MOSFETs. | Targeted at multi-zone architectural lighting with digital addressability, not single-string high-power control. | Choose for distributed, digitally controlled LED arrays rather than single high-current string regulation. |
Compared with LTC3783EFE#PBF and LT3965EFE#PBF, the LT3761IMSE-1#PBF uniquely combines internal PWM generation, SYNC capability, and 60V input support in a single-channel, external-FET controller - making it optimal for high-reliability, EMI-sensitive automotive and industrial LED drivers requiring deterministic timing control.
Availability
LT3761IMSE-1#PBF is available at Aetrix Electronics and suitable for automotive headlamp systems, industrial high-bay lighting, battery charging circuits, and medical surgical lighting requiring stable component supply and long-term production continuity.
Supply support for LT3761IMSE-1#PBF 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 LT3761/LT3761-1 product line was designed specifically for high-efficiency, high-reliability LED current regulation in demanding environments - emphasizing wide input range, robust fault protection, and precision dimming for automotive and industrial lighting.
FAQ
What is the key functional difference between LT3761IMSE-1#PBF and LT3761IMSE#PBF?
The LT3761IMSE-1#PBF replaces the OPENLED fault indicator pin (Pin 9) with a dedicated SYNC input pin, enabling synchronization of the internal oscillator to an external clock source. This allows deterministic phase alignment in multi-controller systems and reduces EMI through frequency dithering. The base LT3761IMSE#PBF retains OPENLED for open-LED fault reporting but lacks synchronization capability. Both share identical current/voltage regulation accuracy, 60V VIN rating, and PWM dimming features.
Can LT3761IMSE-1#PBF drive LEDs in buck configuration?
Yes, LT3761IMSE-1#PBF supports buck, boost, SEPIC, inverting, buck-boost, and flyback topologies. In buck mode, it regulates LED current using low-side current sensing (ISN tied to GND, ISP connected to LED cathode), with FB used for optional overvoltage protection. The controller's flexible current sense architecture and dual-loop regulation make it adaptable across topologies - confirmed in the datasheet's "Drives LEDs in Boost, SEPIC, Inverting, Buck Mode, Buck-Boost Mode, or Flyback Configuration" feature list.
What is the minimum recommended capacitor value for the DIM/SS pin on LT3761IMSE-1#PBF?
The minimum recommended capacitor value for the DIM/SS pin on LT3761IMSE-1#PBF is 560pF, as specified in the Pin Functions section. This capacitor sets the soft-start time and determines the frequency of the internal PWM dimming signal generator when used in self-oscillating mode. Values below 560pF may cause instability in soft-start behavior or inconsistent PWMOUT waveform generation. For reliable operation, place the capacitor close to the IC with short traces to GND.
How does the CTRL pin affect current regulation accuracy in LT3761IMSE-1#PBF?
The CTRL pin on LT3761IMSE-1#PBF linearly adjusts the current sense threshold VISP-ISN from 21mV to 258mV over 0–1.0V, enabling analog dimming and temperature compensation. Below 1.2V, VISP-ISN = (CTRL – 0.1V)/4; above 1.2V, it clamps at full-scale 250mV. This scaling directly impacts LED current accuracy: ILED = VISP-ISN / RSENSE. Since VISP-ISN has ±3% tolerance over temperature, the resulting current regulation maintains ±3% accuracy - verified in Electrical Characteristics tables for both full-scale and mid-scale conditions.
Is LT3761IMSE-1#PBF RoHS-compliant and lead-free?
Yes, LT3761IMSE-1#PBF is RoHS-compliant and lead-free, as indicated by the "#PBF" suffix in its part number and confirmed in the Order Information table. The device uses 100% matte tin lead finish and meets JEDEC J-STD-020 moisture sensitivity level 1 (MSL1) requirements. Packaging is tape-and-reel compatible, and marking code "37611" identifies the LT3761-1 variant. Full compliance documentation is available through Analog Devices' official product page and material declarations.
LT3761IMSE-1#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- True Color PWM™
- 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):
- 60V
- Voltage - Output:
- -
- Current - Output / Channel:
- -
- Frequency:
- 100kHz ~ 1MHz
- Dimming:
- Analog, PWM
- Applications:
- -
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LT3761IMSE-1#PBF FAQ
1.How can I place an order for LT3761IMSE-1#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3761IMSE-1#PBF 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 LT3761IMSE-1#PBF reliable?
The price and inventory of LT3761IMSE-1#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3761IMSE-1#PBF is usually 5 days.
3.What payment methods are accepted for LT3761IMSE-1#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3761IMSE-1#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3761IMSE-1#PBF?
LT3761IMSE-1#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3761IMSE-1#PBF 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 LT3761IMSE-1#PBF?
For technical support, including LT3761IMSE-1#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3761IMSE-1#PBF requirements.
6.How does Aetrix verify that LT3761IMSE-1#PBF is sourced from the original manufacturer or authorized distributors?
All LT3761IMSE-1#PBF 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 LT3761IMSE-1#PBF meets industry standards.
7.What is the process for return or replacement of LT3761IMSE-1#PBF?
All LT3761IMSE-1#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3761IMSE-1#PBF, 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 LT3761IMSE-1#PBF part is unused and in its original packaging.
Return procedure for LT3761IMSE-1#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LT3761IMSE-1#PBF Tags
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