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Texas Instruments LM3444MA/NOPB
- Part No.:
- LM3444MA/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM3444MA/NOPB.pdf
- Description:
- IC LED DRIVER OFFL ANALOG 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,196
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Product details
Overview
LM3444MA/NOPB from Texas Instruments is an adaptive constant off-time AC/DC buck LED driver controller supporting 80–277 VAC input, delivering >1 A constant LED current with programmable switching frequency up to 1 MHz and no 120-Hz flicker in residential lighting systems.
For engineers reviewing the LM3444MA/NOPB datasheet, LM3444MA/NOPB pinout, LM3444MA/NOPB application, or LM3444MA/NOPB equivalent, key selection considerations include its valley-fill PFC compatibility, thermal shutdown at 165°C, 1.276 V ISNS current-sense threshold, COFF-based off-time programming, and dual-package availability (VSSOP-10/SOIC-8).
Technical Context
The LM3444MA/NOPB implements a proprietary adaptive constant off-time control architecture where tOFF is set externally via COFF pin current and capacitor, while tON varies inversely with VBUCK/VLED ratio to maintain constant current. It integrates a valley-fill PFC front-end interface, internal gate driver with 0.5 V saturation voltage, and dual comparators for current limiting (1.27 V) and analog dimming (750 mV reference at FILTER).
Its functional block includes a MOSFET gate driver, ISNS current-sense comparator with 125 ns leading-edge blanking, thermal shutdown latch (165°C trip / 145°C release), UVLO on VCC (7.7 V rise / 6.4 V fall), and passive filter input at FILTER for PWM-to-DC dimming conversion - all operating without external clock or compensation network.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 80–277 VAC line-compatible; enables direct mains connection without pre-regulator |
| LED Current Capability | >1 A output current; supports high-brightness LED strings in commercial lighting |
| Switching Frequency Range | 30 kHz to >1 MHz; adjustable via COFF pin; balances efficiency vs. magnetics size |
| ISNS Threshold Voltage | 1.269 V (typ); sets peak inductor current limit; determines maximum LED current with RSENSE |
| VCC UVLO Threshold | 7.7 V (rising), 6.4 V (falling); ensures stable startup and brownout protection |
| Thermal Shutdown | 165°C (trip), 20°C hysteresis; protects IC during overload or poor heatsinking |
| Quiescent Current | 2.25 mA (typ); minimizes standby power loss in always-on lighting fixtures |
Pinout & Package
LM3444MA/NOPB is packaged in a 10-pin VSSOP (3.00 mm × 3.00 mm) with exposed thermal pad. Pin functions are validated per TI SNVS682D datasheet Rev D.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| COFF (Pin 4) | Off-time programming input | Sinks user-defined current into external RC network to set precise tOFF; enables frequency stability across line/load |
| FILTER (Pin 5) | Analog/PWM dimming interface | Accepts filtered PWM signal or DC voltage to scale LED current; 750 mV reference enables 0–100% dimming range |
| GATE (Pin 8) | MOSFET gate driver output | Drives external N-channel MOSFET with 0.5 V high-side saturation; supports fast switching up to 1 MHz |
| GND (Pin 6) | Power and signal reference | Common return for ISNS sensing, gate drive, and internal regulators; requires low-impedance PCB plane |
| ISNS (Pin 7) | Current sense input | Monitors voltage across external sense resistor; trips at 1.269 V to terminate switch conduction |
| VCC (Pin 9) | Internal supply rail | Powered from auxiliary winding or VBUCK; regulated to 7.5 V internally; powers gate driver and logic |
| NC (Pins 1,2,3,10) | No-connect terminals | Internally unconnected; must remain floating; no pull-up/down or routing required |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive constant off-time control | Enables stable constant-current regulation without loop compensation components; maintains ripple current over wide VBUCK range |
| Valley-fill PFC integration | Supports passive two- or three-stage valley-fill circuits for >0.9 power factor without active PFC controller |
| No-flicker 120-Hz operation | Eliminates visible LED flicker in AC-line-powered designs by maintaining continuous conduction through valley-fill hold-up |
| Programmable thermal shutdown | 165°C junction trip with 20°C hysteresis prevents thermal runaway while allowing safe recovery without system reset |
| Low quiescent current | 2.25 mA typical VCC supply current reduces standby losses in smart lighting and IoT-connected luminaires |
Applications
| Residential LED Luminaires | Commercial Downlights |
|---|---|
Use Scenario: Integrated LED bulb or retrofit lamp operating directly from 120/230 VAC mains with TRIAC dimmer compatibility. IC Role / Device Role / Timing Role: Constant-current buck controller managing LED string current while interfacing with valley-fill PFC and analog-dimming circuitry. Use Value: Delivers flicker-free illumination with >85% efficiency and <1% current variation across line voltage swings. | Use Scenario: High-lumen ceiling-mounted downlight used in offices and retail spaces requiring long life and thermal robustness. IC Role / Device Role / Timing Role: Primary LED current regulator in isolated or non-isolated buck topology with programmable tOFF for optimal EMI performance. Use Value: Enables compact form factor via 1 MHz switching and eliminates external compensation, reducing BOM count by 3–5 components. |
| Industrial Area Lighting | Streetlight Retrofit Modules |
Use Scenario: High-bay fixture in warehouse environments subject to wide ambient temperature (-40°C to +85°C) and voltage fluctuations. IC Role / Device Role / Timing Role: Adaptive off-time controller maintaining ±3% LED current accuracy despite VBUCK variation from 40 V to 90 V. Use Value: Thermal shutdown and UVLO ensure reliable restart after overtemperature events; 125°C max junction rating supports sealed enclosures. | Use Scenario: LED driver module replacing HID ballasts in existing streetlight poles with 100–277 VAC input range. IC Role / Device Role / Timing Role: Mains-connected LED driver IC implementing passive PFC and constant-current regulation for 14-series LED strings. Use Value: Achieves >90% efficiency at 140 VAC input with 14 LEDs, meeting DLC Premium requirements without active PFC IC. |
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 |
|---|---|---|---|
| LM3445MM/NOPB | Fixed-frequency (not adaptive off-time); requires external oscillator; lacks FILTER pin for analog dimming | Better suited for fixed-frequency EMI-constrained designs; no native PWM-to-DC dimming support | Select when deterministic fSW is mandatory and dimming is digital-only |
| NCP1075DR2G | Fixed-frequency flyback controller with integrated HV start-up; no valley-fill PFC support; lower max current (700 mA) | Targets lower-power (<15 W), isolated flyback topologies; not compatible with buck+valley-fill architecture | Select for cost-sensitive, isolated, sub-1 A applications where PFC is secondary |
Compared with LM3445MM/NOPB and NCP1075DR2G, the LM3444MA/NOPB uniquely combines adaptive off-time control, integrated valley-fill PFC interface, analog dimming capability, and >1 A drive strength - making it the only option among the three qualified for high-efficiency, non-isolated, mains-direct LED drivers with flicker-free dimming.
Availability
LM3444MA/NOPB is available at Aetrix Electronics and suitable for residential lighting, commercial downlights, and industrial area lighting requiring stable component supply, long-lifecycle assurance, and full traceability.
Supply support for LM3444MA/NOPB 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 designing analog ICs, embedded processors, and power management solutions for industrial, automotive, and consumer applications.
The LM3444MA/NOPB belongs to TI's AC/DC LED driver controller product line, engineered specifically for non-isolated, high-efficiency, mains-powered LED lighting with integrated passive PFC and flicker-free operation.
FAQ
What is the recommended minimum on-time for stable operation of the LM3444MA/NOPB?
The LM3444MA/NOPB specifies a minimum on-time of 200 ns in the datasheet. This limit constrains the maximum achievable switching frequency - especially at high VBUCK and low VLED conditions. Designers must verify tON(MIN) = VLED(MIN) / (VBUCK(MAX) × fSW) stays above 200 ns to avoid pulse-skipping or regulation loss. The LM3444MA/NOPB's adaptive off-time architecture helps maintain stability within this boundary.
Does the LM3444MA/NOPB support TRIAC dimmer compatibility?
The LM3444MA/NOPB itself does not integrate TRIAC phase-cut decoding, but it supports TRIAC-dimmable systems when paired with a compatible valley-fill front-end and downstream analog dimming circuit. Its FILTER pin accepts a smoothed DC voltage derived from the TRIAC output, enabling proportional LED current reduction. Successful implementation requires careful matching of hold-up capacitance and dimming filter time constants - a design verified in TI reference design TIPD180 using LM3444MA/NOPB.
What is the function of the COFF pin on the LM3444MA/NOPB and how is it configured?
The COFF pin on the LM3444MA/NOPB sets the constant off-time duration by sinking a precision current into an external RC network. A resistor (e.g., 348 kΩ) from VCC to COFF and capacitor (e.g., 2.2 nF) from COFF to GND program tOFF ≈ R × C × 1.276 V. This configuration enables predictable switching frequency scaling with LED string voltage - a core feature distinguishing LM3444MA/NOPB from fixed-frequency controllers. The LM3444MA/NOPB datasheet provides exact design equations in Section 8.1.2.
Can the LM3444MA/NOPB drive more than one LED string in parallel?
No - the LM3444MA/NOPB regulates current in a single LED string via its ISNS pin, which senses voltage across one shared sense resistor. Driving multiple parallel strings would cause current imbalance due to VF mismatch, risking thermal runaway. For multi-string applications, TI recommends using separate LM3444MA/NOPB channels or selecting a multi-channel controller like the TPS92641. The LM3444MA/NOPB's architecture is intentionally optimized for single-string, high-current, high-efficiency operation.
What thermal management guidance applies to the LM3444MA/NOPB in a 10-pin VSSOP package?
The LM3444MA/NOPB in VSSOP-10 has RθJA = 163.8°C/W (JEDEC standard board). To maintain TJ ≤ 125°C at full load, PCB layout must include ≥ 200 mm² copper pour under the exposed thermal pad, connected to internal ground planes via ≥ 4 thermal vias (0.3 mm diameter). Ambient temperature derating is required above 60°C; for example, at 85°C ambient, max power dissipation drops to ~360 mW. TI's Layout Guidelines (Section 10.1) mandate short, wide traces for ISNS, GATE, and COFF to minimize noise coupling - critical for stable LM3444MA/NOPB operation.
LM3444MA/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- 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:
- -
- Current - Output / Channel:
- -
- Frequency:
- -
- Dimming:
- Analog
- Applications:
- Lighting
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
LM3444MA/NOPB FAQ
1.How can I place an order for LM3444MA/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3444MA/NOPB 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 LM3444MA/NOPB reliable?
The price and inventory of LM3444MA/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3444MA/NOPB is usually 5 days.
3.What payment methods are accepted for LM3444MA/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3444MA/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3444MA/NOPB?
LM3444MA/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3444MA/NOPB 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 LM3444MA/NOPB?
For technical support, including LM3444MA/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3444MA/NOPB requirements.
6.How does Aetrix verify that LM3444MA/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3444MA/NOPB 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 LM3444MA/NOPB meets industry standards.
7.What is the process for return or replacement of LM3444MA/NOPB?
All LM3444MA/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3444MA/NOPB, 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 LM3444MA/NOPB part is unused and in its original packaging.
Return procedure for LM3444MA/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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