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Texas Instruments LM3444MMX/S7002724
- Part No.:
- LM3444MMX/S7002724
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LM3444MMX/S7002724.pdf
- Description:
- PROTOTYPE
- Quantity:
- Payment:
- Shipping:
Inventory:2,283
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Product details
Overview
LM3444MMX/S7002724 from Texas Instruments is a constant off-time AC/DC buck LED driver controller for offline solid-state lighting, supporting 80–277 VAC input, delivering >1 A constant LED current, and operating with adaptive off-time control to maintain ripple-current stability across varying line voltages and LED string configurations.
For engineers reviewing the LM3444MMX/S7002724 datasheet, LM3444MMX/S7002724 pinout, LM3444MMX/S7002724 application, or LM3444MMX/S7002724 equivalent, key selection considerations include its valley-fill PFC compatibility, thermal shutdown behavior at 165°C, COFF-programmable switching frequency (30 kHz–1 MHz), and dual-package availability (VSSOP-10/SOIC-8) for layout flexibility in commercial and industrial LED drivers.
Technical Context
The LM3444MMX/S7002724 implements a proprietary adaptive constant off-time control architecture where tOFF is set externally via COFF pin (1.276 V threshold, 33–60 Ω sink impedance), enabling stable current regulation despite wide VBUCK variation (e.g., 50–200 V). Its internal current-sense comparator uses a 750 mV reference at FILTER and 1.269 V ISNS limit threshold to trigger MOSFET turn-off.
It integrates passive PFC support via valley-fill circuit interface (D3/C7/C9/C10), operates with leading-edge blanking (125 ns), and features thermal shutdown with 20°C hysteresis (trip at 165°C, release at 145°C), ensuring robust operation under sustained overload or high ambient conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 80–277 VAC mains-compatible; enables direct connection to global AC infrastructure without pre-regulation. |
| LED Current Capability | >1 A output current; supports high-lumen LED strings in commercial lighting fixtures. |
| Switching Frequency Range | 30 kHz to >1 MHz; programmable via COFF pin and external R/C network for EMI and efficiency trade-offs. |
| ISNS Current Limit Threshold | 1.269 V (typ); sets maximum peak inductor current by sensing voltage across R3, enabling precise ILED calibration. |
| Thermal Shutdown | 165°C trip temperature with 20°C hysteresis; prevents permanent damage during thermal overload while allowing safe recovery. |
| Package Options | VSSOP-10 (3.0 × 3.0 mm) and SOIC-8 (3.91 × 4.90 mm); compact footprints suitable for space-constrained LED driver PCBs. |
| Quiescent Current | 2.25 mA (typ); minimizes standby power loss in always-on lighting applications. |
Pinout & Package
LM3444MMX/S7002724 is available in a low-profile 10-pin VSSOP package (3.00 mm × 3.00 mm body size) with exposed thermal pad for enhanced power dissipation in LED driver applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| COFF | Off-time programming input | Connects to RC network setting constant tOFF; determines switching frequency and ripple-current stability. |
| FILTER | Analog/PWM dimming interface | Accepts filtered DC or PWM signal to adjust LED current; internal 750 mV reference enables analog dimming down to 0%. |
| GATE | MOSFET gate driver output | Drives external N-channel MOSFET (Q2) with 0.5 V saturation drop at 100 mA sink; supports fast switching up to 1 MHz. |
| GND | Power and signal reference | Common return path for ISNS sense resistor, internal regulators, and gate drive return; requires low-impedance PCB plane. |
| ISNS | Current sense input | Monitors voltage across R3 to detect peak inductor current; trips at 1.269 V to terminate on-time and regulate average LED current. |
| VCC | Internal supply rail | Provides bias for control logic and gate driver; regulated from VBUCK via internal LDO; UVLO thresholds at 6.4 V (falling) / 7.7 V (rising). |
| NC | No-connect terminals | Pins 1, 2, 3, and 10 are unconnected internally; must remain floating per datasheet to avoid parasitic coupling. |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive constant off-time control | Maintains consistent LED current ripple across 80–277 VAC input range and varying LED string voltages (e.g., 3–14 LEDs), eliminating need for complex compensation. |
| Valley-fill PFC interface | Supports 2- or 3-stage passive PFC circuits (D3/C7/C9/C10) to achieve >0.9 power factor without active PFC ICs or controllers. |
| No-flicker 120 Hz operation | Eliminates visible flicker in AC-driven LED systems by maintaining continuous conduction mode (CCM) and synchronized current regulation across full AC cycle. |
| Integrated thermal protection | Auto-shutdown at 165°C junction temperature with 20°C hysteresis ensures reliable operation in enclosed luminaires without external thermal sensors. |
| Low quiescent current | 2.25 mA typical VCC supply current reduces no-load losses, improving system efficiency in standby or dimmed states. |
Applications
| Industrial High-Bay Lighting | Commercial Downlight Fixtures |
|---|---|
Use Scenario: High-efficiency LED retrofit for 20–40 ft ceiling warehouses using 10–14 series-connected LEDs driven from 277 VAC line. IC Role / Device Role / Timing Role: Constant-current buck controller regulating LED string current while interfacing with valley-fill PFC stage to meet IEEE 1547 harmonic limits. Use Value: Delivers >90% efficiency at full load with <5% current ripple, enabling thermal derating margin for 50,000-hour lumen maintenance. | Use Scenario: Slim-profile architectural downlight operating from 120 VAC with analog-dimming interface and thermal foldback. IC Role / Device Role / Timing Role: Adaptive off-time LED driver providing smooth 0–100% analog dimming via FILTER pin while maintaining constant current despite input voltage sags. Use Value: Eliminates 120 Hz flicker and supports Class B EMI compliance with minimal external components due to fixed tOFF architecture. |
| Residential Outdoor Floodlights | Smart Streetlight Drivers |
Use Scenario: Weatherproof outdoor floodlight powered from 120/240 VAC with overtemperature protection and surge immunity. IC Role / Device Role / Timing Role: Primary-side LED controller managing buck stage and thermal shutdown response without secondary-side feedback. Use Value: Enables IP66-rated design with single-layer PCB layout; thermal shutdown at 165°C prevents LED degradation during summer ambient exposure. | Use Scenario: Networked streetlight with DALI or 0–10 V dimming interface and long-life reliability requirements. IC Role / Device Role / Timing Role: Core current regulator accepting analog dimming input on FILTER pin while maintaining constant current across 80–277 VAC universal input range. Use Value: Supports firmware-upgradable dimming profiles and meets IEC 61000-3-2 Class C harmonic limits via integrated valley-fill PFC support. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar AC/DC LED driver controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC28810DR | Fixed-frequency (50–500 kHz) flyback controller with integrated 600 V MOSFET; lacks adaptive off-time and valley-fill PFC interface. | Targets lower-power (<30 W), isolated LED drivers; not suitable for non-isolated buck topologies or high-current >1 A designs. | Select UCC28810DR only when isolation, lower BOM count, or flyback topology is required-LM3444MMX/S7002724 remains preferred for non-isolated, high-efficiency buck drivers. |
| NCP1075P | Fixed-frequency (65 kHz) quasi-resonant flyback controller with integrated 700 V MOSFET; no analog dimming or valley-fill support. | Designed for cost-sensitive, low-to-mid power (<25 W) isolated LED bulbs; lacks programmable tOFF, thermal hysteresis, and high-current capability. | Choose NCP1075P for simple, low-cost bulb replacements; LM3444MMX/S7002724 is superior for high-power, non-isolated, thermally demanding fixtures requiring precise current regulation. |
Compared with UCC28810DR and NCP1075P, the LM3444MMX/S7002724 uniquely combines adaptive off-time control, valley-fill PFC compatibility, and >1 A current capability in a single non-isolated buck controller-making it the only option among the three that supports high-efficiency, high-power, thermally robust commercial LED drivers without transformer isolation.
Availability
LM3444MMX/S7002724 is available at Aetrix Electronics and suitable for industrial high-bay lighting, commercial downlight fixtures, and residential outdoor floodlights requiring stable component supply and long-term production continuity.
Supply support for LM3444MMX/S7002724 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
Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and power management technologies, with decades of experience in LED driver innovation and energy-efficient power conversion.
The LM3444 product line was designed specifically for cost-effective, high-efficiency, non-isolated AC/DC LED drivers targeting commercial and industrial solid-state lighting applications requiring passive PFC, analog dimming, and thermal resilience.
FAQ
What is the primary function of the LM3444MMX/S7002724 in an LED driver circuit?
The LM3444MMX/S7002724 functions as a constant off-time AC/DC buck LED driver controller. It regulates LED current by adaptively controlling the MOSFET gate drive (GATE pin) based on voltage sensed across the ISNS resistor, while interfacing with a valley-fill PFC stage to ensure high power factor and low THD. Its core purpose is to deliver stable, flicker-free current to high-power LED strings directly from AC mains.
How does the COFF pin affect switching frequency in the LM3444MMX/S7002724?
The COFF pin sets the constant off-time (tOFF) via an external RC network, where capacitor C11 and resistor R4 determine the charging current into C11. Since tOFF remains fixed while tON varies with VBUCK, the resulting switching frequency fSW = 1/(tON + tOFF) changes inversely with input voltage - higher VBUCK yields higher fSW. This adaptive behavior maintains stable current ripple across 80–277 VAC input.
Can the LM3444MMX/S7002724 support analog dimming, and how is it implemented?
Yes, the LM3444MMX/S7002724 supports analog dimming through the FILTER pin, which accepts a DC voltage (0–750 mV) to scale the internal current-sense reference. Applying 0 V disables LED current; 750 mV enables full-scale current. A low-pass filter (e.g., RC network) can convert PWM signals to DC for smooth dimming. No external op-amp or DAC is required - dimming is fully integrated and compatible with 0–10 V control systems.
What thermal protection features does the LM3444MMX/S7002724 include?
The LM3444MMX/S7002724 includes thermal shutdown with a trip point of 165°C (typical) and automatic recovery at ~145°C (20°C hysteresis). When junction temperature exceeds 165°C, the GATE output is disabled until temperature falls below the release threshold. This protects both the IC and external MOSFET from thermal runaway in enclosed or high-ambient environments - critical for outdoor and high-bay LED fixtures.
Is the LM3444MMX/S7002724 compatible with passive PFC topologies, and which ones?
Yes, the LM3444MMX/S7002724 is explicitly designed for use with passive valley-fill PFC circuits. It supports both two-stage and three-stage valley-fill configurations (e.g., D3/C7/C9/C10 networks) that improve power factor to >0.9 and reduce input current harmonics to meet IEC 61000-3-2 Class C limits. The IC interfaces directly with the VBUCK rail generated by these circuits and requires no additional PFC controller or feedback loop.
LM3444MMX/S7002724 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Type:
- AC DC Offline Switcher
- Topology:
- Step-Down (Buck)
- Internal Switch(s):
- No
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 8V
- Voltage - Supply (Max):
- 13V
- Voltage - Output:
- 9V ~ 60V
- Current - Output / Channel:
- 2A
- Frequency:
- 350kHz
- Dimming:
- Analog, PWM
- Applications:
- Lighting
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-VSSOP
LM3444MMX/S7002724 FAQ
1.How can I place an order for LM3444MMX/S7002724 through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3444MMX/S7002724 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 LM3444MMX/S7002724 reliable?
The price and inventory of LM3444MMX/S7002724 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3444MMX/S7002724 is usually 5 days.
3.What payment methods are accepted for LM3444MMX/S7002724?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3444MMX/S7002724 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3444MMX/S7002724?
LM3444MMX/S7002724 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3444MMX/S7002724 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 LM3444MMX/S7002724?
For technical support, including LM3444MMX/S7002724 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3444MMX/S7002724 requirements.
6.How does Aetrix verify that LM3444MMX/S7002724 is sourced from the original manufacturer or authorized distributors?
All LM3444MMX/S7002724 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 LM3444MMX/S7002724 meets industry standards.
7.What is the process for return or replacement of LM3444MMX/S7002724?
All LM3444MMX/S7002724 units undergo pre-shipment inspection (PSI). If there is an issue with LM3444MMX/S7002724, 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 LM3444MMX/S7002724 part is unused and in its original packaging.
Return procedure for LM3444MMX/S7002724:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3444MMX/S7002724 Tags
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