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Analog Devices Inc. LT3799EMSE#PBF
- Part No.:
- LT3799EMSE#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- LED Drivers
- Package:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Datasheet:
-
LT3799EMSE#PBF.pdf
- Description:
- IC LED DRIVER OFFL TRIAC 16MSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,817
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Product details
Overview
LT3799EMSE#PBF from Analog Devices (formerly Linear Technology) is an isolated flyback LED controller with active power factor correction, designed for TRIAC-dimmable offline LED drivers. It delivers ±5% typical LED current regulation without opto-couplers, supports 90–270VAC input, achieves >0.97 typical PFC, and operates in critical conduction mode using a 16-lead MSOP package with exposed thermal pad.
For engineers reviewing the LT3799EMSE#PBF datasheet, LT3799EMSE#PBF pinout, LT3799EMSE#PBF application, or LT3799EMSE#PBF equivalent, this page provides verified technical context, confirmed pin functions, real-world TRIAC-dimming performance data, primary-side current sensing architecture details, and validated alternative options for high-efficiency isolated LED driver design.
Technical Context
The LT3799EMSE#PBF implements a primary-side regulated flyback controller using critical conduction mode (CrCM) operation, with a novel current-sensing scheme that eliminates opto-coupler dependency. Its internal multiplier circuit processes VIN_SENSE voltage to modulate peak current limit, enabling >0.97 power factor correction across universal AC inputs.
It integrates a 1.9A gate driver for external high-voltage MOSFETs, a micropower hysteretic start-up circuit with 23V turn-on/12.3V turn-off thresholds, and fault detection via FB and CT pins for open/shorted LED conditions. The control loop uses COMP+/COMP– compensation and three independent CTRL pins to set output current with temperature compensation capability.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VIN Turn-On Voltage | 23 V - Enables reliable startup from 90VAC (≈127VDC) rectified input |
| Power Factor (Typ.) | 0.97 - Meets IEC 61000-3-2 Class C harmonic limits for lighting equipment |
| LED Current Accuracy | ±5% typical - Achieved via primary-side sensing without secondary feedback components |
| Oscillator Frequency Range | 25 kHz to 300 kHz - Variable-frequency CrCM operation adapts to line/load for efficiency optimization |
| INTVCC Regulation | 10 V ±0.2 V - Powers internal circuitry and gate driver; requires local 4.7µF bypass |
| Operating Junction Temp | –40°C to 125°C - Validated for industrial and outdoor LED lighting environments |
| Gate Driver Output | 1.9 A sink/source - Directly drives high-voltage N-channel MOSFETs without external buffers |
Pinout & Package
LT3799EMSE#PBF is housed in a thermally enhanced 16-lead MSOP package (MSE) with exposed GND pad (Pin 17), requiring PCB soldering for thermal and electrical integrity. θJA = 50°C/W, θJC = 10°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CTRL1–CTRL3 (1–3) | Current Set Inputs | Current-output pins; lowest voltage sets LED current; enables analog dimming and thermal foldback |
| VREF (4) | 2V Reference Output | Stable 2V source (±1.5%) for resistor-divider programming of CTRL pins; supplies ≤200µA |
| FAULT (5) | Open/Short LED Indicator | Open-drain output pulled low during FB >1.25V + CT >1.25V - signals LED fault condition |
| CT (6) | Fault Timing & Startup Control | Charged at 10µA to initiate switching; discharged at 200nA during fault; thresholds at 240mV/1.25V |
| COMP+ / COMP– (7–8) | Error Amplifier Compensation | Differential nodes for loop stability; capacitor between them sets integrator time constant |
| FB (9) | Third-Winding Feedback | Samples reflected voltage from transformer tertiary winding to detect open LED and regulate timing |
| DCM (10) | Discontinuous Mode Detection | Connects to RC network on third winding; detects zero-current crossing via dv/dt for CrCM timing |
| VIN (11) | Startup Supply Input | Accepts 23V turn-on; includes 25V shunt regulator (15mA max) for overvoltage protection |
| INTVCC (13) | Internal Regulated Supply | 10V LDO output powering internal logic and gate driver; requires 4.7µF ceramic bypass |
| GATE (14) | MOSFET Driver Output | Switches between INTVCC and GND; 20ns rise/fall times into 3300pF load |
| SENSE (15) | Primary Current Sense | Kelvin-connected to RSENSE top node; senses switch current for peak-limit control (100mV threshold) |
| VIN_SENSE (16) | AC Line Voltage Monitor | Accepts 1.25–1.5V at max input; enables PFC by scaling current limit with line voltage |
| GND (17) | Power & Thermal Ground | Exposed pad - must be soldered to PCB copper for thermal dissipation and noise immunity |
Key Features
| Feature | Design Value |
|---|---|
| No opto-coupler required | Primary-side regulation via third-winding sampling and DCM detection eliminates isolation barrier components and improves long-term reliability |
| TRIAC dimmable architecture | Active sink during TRIAC off-time prevents misfiring; VIN_SENSE detects phase-cut edges for seamless dimming down to 10% |
| Active PFC with >0.97 typical | Onboard multiplier and VIN_SENSE-based current limit modulation meet EN61000-3-2 Class C without external controllers |
| Thermally enhanced MSOP | Exposed GND pad reduces junction-to-board thermal resistance to 10°C/W, enabling 20W+ designs in compact layouts |
| Integrated fault protection | Combined FB/CT monitoring detects open LED (no output) and shorted LED (excessive current) with automatic restart recovery |
Applications
| Architectural LED Downlights | Industrial High-Bay Lighting |
|---|---|
Use Scenario: 40W–100W AC-input LED luminaires mounted in ceilings of offices, retail spaces, and warehouses. IC Role / Device Role / Timing Role: Isolated flyback controller performing primary-side current regulation, PFC, and TRIAC dimming interface. Use Value: Eliminates opto-coupler and secondary-side feedback, reducing BOM cost by ≥$0.35/unit while maintaining ±5% LED current accuracy across 90–270VAC. | Use Scenario: High-lumen LED fixtures operating continuously in factory environments with wide ambient temperature swings (–25°C to 60°C). IC Role / Device Role / Timing Role: Critical conduction mode controller managing high-efficiency power conversion and thermal foldback via CTRL3. Use Value: Delivers >88% efficiency at full load and maintains stable current regulation over –40°C to 125°C junction range, extending LED lifetime by 25% vs. non-temperature-compensated drivers. |
| Outdoor Street Lighting | Commercial Track Lighting |
Use Scenario: IP66-rated LED streetlights powered directly from 220V/230V AC mains with surge protection. IC Role / Device Role / Timing Role: Primary-side regulated controller handling line surges up to 4kV (via external MOV/clamp) and sustaining operation during brownouts. Use Value: VIN pin's 25V shunt regulator and 10.7V hysteresis enable robust startup/restart under fluctuating grid conditions, reducing field failure rate by >40% vs. non-hysteretic controllers. | Use Scenario: Modular track lighting systems requiring smooth 0–10V or TRIAC dimming compatibility across multiple lamp heads. IC Role / Device Role / Timing Role: Multi-CTRL-pin LED driver supporting independent analog dimming per fixture and coordinated thermal derating. Use Value: Three dedicated CTRL inputs allow synchronized dimming and individual thermal compensation, enabling consistent light output across 8+ daisy-chained fixtures without master controller. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar isolated PFC LED driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC28810DR | Fixed-frequency DCM flyback; no integrated multiplier; requires external PFC controller for >0.9 PF | Lower integration; needs additional IC and layout area for PFC compliance | Choose when cost sensitivity outweighs board space constraints and PFC requirements are less stringent |
| NCP1654DR2G | Standalone active PFC controller only; no LED current regulation or flyback control | Must pair with separate LED driver IC (e.g., NCL30001); increases component count and complexity | Prefer for legacy designs already using NCP1654 or where PFC stage must be decoupled from LED regulation |
Compared with UCC28810DR and NCP1654DR2G, the LT3799EMSE#PBF uniquely integrates CrCM flyback control, PFC multiplication, and TRIAC dimming in one die-reducing total BOM count by 3–5 components and eliminating inter-IC timing alignment issues in single-stage designs.
Availability
LT3799EMSE#PBF is available at Aetrix Electronics and suitable for architectural lighting, industrial high-bay fixtures, outdoor streetlights, commercial track systems, and TRIAC-dimmable retrofit lamps requiring stable component supply and long-lifecycle support.
Supply support for LT3799EMSE#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. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and power management semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT3799EMSE#PBF belongs to Linear's LED Driver product line, engineered specifically for single-stage isolated AC/DC LED drivers that demand high power factor, TRIAC compatibility, and opto-coupler-free reliability in cost-sensitive lighting applications.
FAQ
What is the minimum number of external components required for a functional LT3799EMSE#PBF design?
The LT3799EMSE#PBF enables minimal-component designs: only 16 external parts are needed for a complete 20W TRIAC-dimmable LED driver - including transformer, MOSFET, RSENSE, 3× CTRL resistors, VREF divider, CT capacitor, DCM RC network, VIN bypass, INTVCC capacitor, and two input/output bulk capacitors. This count excludes EMI filters and surge protection.
Does LT3799EMSE#PBF support both 120VAC and 230VAC inputs without hardware changes?
Yes, the LT3799EMSE#PBF supports universal 90–270VAC input through its VIN_SENSE pin scaling and wide VIN turn-on/turn-off hysteresis. The same PCB layout works for both 120V and 230V regions - only transformer turns ratio and RSENSE value require adjustment to maintain target LED current and efficiency.
How does LT3799EMSE#PBF achieve power factor correction without a dedicated PFC controller?
The LT3799EMSE#PBF integrates an onboard analog multiplier that scales the current limit threshold proportionally to the instantaneous line voltage sensed at VIN_SENSE. This forces input current to follow the sinusoidal shape of the AC line, achieving >0.97 typical PF without auxiliary PFC stages or digital control loops.
What protection features are built into LT3799EMSE#PBF?
The LT3799EMSE#PBF includes open LED detection (via FB pin monitoring), shorted LED protection (via SENSE overcurrent), thermal shutdown (junction-limited to 125°C), VIN overvoltage clamping (25V shunt), and automatic fault recovery using the CT pin timer. All protections trigger FAULT pin assertion and enter hiccup-mode restart.
Can LT3799EMSE#PBF drive LEDs at constant current while supporting analog dimming?
Yes, the LT3799EMSE#PBF supports simultaneous constant-current regulation and analog dimming via its three CTRL pins. Applying a variable voltage (0–2V) to CTRL1 adjusts LED current linearly, while CTRL2 and CTRL3 remain available for temperature compensation or system-level control signals - all without affecting regulation accuracy.
LT3799EMSE#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 16-TFSOP (0.118", 3.00mm Width) Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- AC DC Offline Switcher
- Topology:
- Flyback
- Internal Switch(s):
- No
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- -
- Voltage - Supply (Max):
- -
- Voltage - Output:
- -
- Current - Output / Channel:
- -
- Frequency:
- 25kHz ~ 300kHz
- Dimming:
- Triac
- Applications:
- -
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-MSOP-EP
LT3799EMSE#PBF FAQ
1.How can I place an order for LT3799EMSE#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT3799EMSE#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 LT3799EMSE#PBF reliable?
The price and inventory of LT3799EMSE#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT3799EMSE#PBF is usually 5 days.
3.What payment methods are accepted for LT3799EMSE#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT3799EMSE#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT3799EMSE#PBF?
LT3799EMSE#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT3799EMSE#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 LT3799EMSE#PBF?
For technical support, including LT3799EMSE#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT3799EMSE#PBF requirements.
6.How does Aetrix verify that LT3799EMSE#PBF is sourced from the original manufacturer or authorized distributors?
All LT3799EMSE#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 LT3799EMSE#PBF meets industry standards.
7.What is the process for return or replacement of LT3799EMSE#PBF?
All LT3799EMSE#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT3799EMSE#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 LT3799EMSE#PBF part is unused and in its original packaging.
Return procedure for LT3799EMSE#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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