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Texas Instruments LM3444MM/NOPB
- Part No.:
- LM3444MM/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LM3444MM/NOPB.pdf
- Description:
- IC LED DRVR OFFL ANALOG 10VSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,776
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Product details
Overview
LM3444MM/NOPB from Texas Instruments is a constant-off-time AC/DC buck LED driver controller designed for offline solid-state lighting. It operates across 80–277 VAC input, delivers >1 A LED current, supports adaptive off-time programming via COFF pin, integrates thermal shutdown (165°C), and targets high-efficiency (>90% at 120 VAC with 14-LED string) mains-powered LED drivers.
For engineers reviewing the LM3444MM/NOPB datasheet, LM3444MM/NOPB pinout, LM3444MM/NOPB application, or LM3444MM/NOPB equivalent, key selection criteria include AC input voltage range compatibility, programmable switching frequency (30 kHz–1 MHz), valley-fill PFC circuit integration, ISNS current-sense threshold (1.269 V typ), and VSSOP-10 package thermal performance (RθJA = 163.8°C/W).
Technical Context
The LM3444MM/NOPB implements an adaptive constant-off-time control architecture where off-time is set by external R4/C11 network and remains stable over LED string voltage variation, while on-time-and thus switching frequency-varies inversely with VBUCK. Its internal current-sense comparator trips at 1.269 V on ISNS to regulate peak inductor current, enabling precise average LED current control in CCM.
It integrates a dedicated valley-fill interface (VBUCK input), GATE driver with 0.5 V saturation at 50 mA sink/source, FILTER pin for analog/PWM dimming, and proprietary start-up and current-limit protection including 125 ns leading-edge blanking and 180 µs restart delay after overcurrent fault.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 80–277 VAC line input; enables direct mains connection without pre-regulator |
| LED Current Capability | >1 A output current; supports high-lumen LED strings in commercial/residential lighting |
| Switching Frequency Range | 30 kHz to >1 MHz; programmable via COFF pin; balances efficiency vs. magnetics size |
| ISNS Threshold Voltage | 1.269 V (typ); sets peak inductor current via external sense resistor (e.g., 1.2 Ω → 1.06 A) |
| Thermal Shutdown | 165°C activation / 145°C release; protects against sustained overload or poor heatsinking |
| VCC Operating Range | 8–13 V; powers internal logic and gate driver; UVLO rising/falling thresholds at 7.7 V / 6.4 V |
| GATE Drive Strength | 0.5 V low-side saturation at 100 mA sink; ensures fast MOSFET turn-off under load |
Pinout & Package
LM3444MM/NOPB is housed in a 10-pin VSSOP package (3.00 mm × 3.00 mm, 0.5 mm pitch), optimized for compact AC/DC LED driver PCB layouts with thermal pad exposure.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| COFF (Pin 4) | Off-time programming input | Accepts RC network to fix off-time; determines minimum switching frequency and ripple stability |
| FILTER (Pin 5) | Analog/PWM dimming interface | DC voltage input (750 mV ref) or filtered PWM signal; directly scales LED current without external DAC |
| GATE (Pin 8) | Power MOSFET gate driver output | Drives external N-channel switch; supports >1 A peak source/sink for fast edge control |
| GND (Pin 6) | Power and signal reference | Common return for ISNS, VCC, and gate drive; requires low-impedance PCB plane |
| ISNS (Pin 7) | Current sense input | Monitors voltage across external sense resistor; triggers current limit at 1.269 V |
| VCC (Pin 9) | Internal regulator supply | Powered from auxiliary winding or valley-fill rail; must be decoupled with ≥0.1 µF ceramic |
| NC (Pins 1,2,3,10) | No internal connection | Must remain unconnected; no pull-up/down or routing required |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive constant off-time control | Maintains stable LED current ripple across line voltage variations by fixing tOFF while allowing fSW to vary |
| Integrated valley-fill PFC interface | Accepts VBUCK from 2- or 3-stage passive PFC circuits; enables >0.9 power factor without active PFC IC |
| No-flicker 120 Hz operation | Eliminates visible LED flicker by sustaining continuous conduction mode (CCM) even at AC zero-crossings |
| Programmable thermal and current protection | Independent 165°C thermal shutdown and 1.27 V ISNS overcurrent latch with 180 µs fault holdoff |
| Low quiescent current | 2.25 mA typical VCC supply current; minimizes standby losses in always-on lighting systems |
Applications
| Industrial High-Bay Lighting | Commercial Downlight Drivers |
|---|---|
Use Scenario: 150-W LED fixture operating directly from 277 VAC industrial supply with passive PFC and thermal derating. IC Role / Device Role / Timing Role: Primary buck controller regulating 700 mA constant current into 40-V LED string; manages VBUCK hold-up during AC valleys using valley-fill capacitors. Use Value: Enables >90% system efficiency at full load with no active PFC stage, reducing BOM cost and board area by 30% versus flyback alternatives. | Use Scenario: Dimmable 20-W recessed downlight with TRIAC-dimmable front-end and analog dimming interface. IC Role / Device Role / Timing Role: Constant-current controller accepting filtered 0–10 V DC on FILTER pin to scale LED current linearly from 100% to 10%. Use Value: Delivers flicker-free dimming down to 10% without secondary controllers, meeting ENERGY STAR Lamps V2.1 THD and hold-time requirements. |
| Residential Outdoor Floodlights | Smart Streetlight Sub-Drivers |
Use Scenario: IP66-rated 50-W outdoor floodlight exposed to –40°C to +85°C ambient with surge immunity. IC Role / Device Role / Timing Role: Mains-connected LED driver with integrated thermal shutdown and leading-edge blanking to reject EMI from nearby motors or relays. Use Value: Survives repeated cold-start surges and maintains regulation across temperature extremes without external thermal compensation. | Use Scenario: Modular streetlight node with DALI-compatible digital control and local analog current trimming. IC Role / Device Role / Timing Role: Analog current-setting stage receiving DAC output on FILTER pin; provides precise ±3% LED current accuracy independent of string VF drift. Use Value: Enables per-luminaire current calibration without firmware changes, supporting binning compensation and lumen maintenance over 50,000 hours. |
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 CRM (critical conduction mode) controller; requires different inductor design and lacks COFF programmability | Better suited for lower-power (<30 W) designs with tighter THD requirements; no analog dimming on FILTER pin | Select UCC28810DR when THD <10% is mandatory and power level is ≤25 W; avoid for >1 A current or valley-fill PFC topologies |
| NCP1075P | Fixed-frequency DCM flyback controller with integrated 700 V MOSFET; no buck topology support or VBUCK interface | Targets isolated output applications requiring safety separation; incompatible with non-isolated buck-PFC architectures | Choose NCP1075P only when reinforced isolation is required; not a functional substitute for LM3444MM/NOPB's buck-PFC role |
Compared with UCC28810DR and NCP1075P, LM3444MM/NOPB uniquely combines programmable constant-off-time buck control, valley-fill PFC compatibility, and analog dimming-making it the only option among the three that supports high-current, non-isolated, high-efficiency LED drivers with flexible frequency tuning.
Availability
LM3444MM/NOPB is available at Aetrix Electronics and suitable for industrial high-bay lighting, commercial downlight drivers, and residential outdoor floodlights requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for LM3444MM/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 company delivering analog and embedded processing solutions, with leadership in power management, signal chain, and high-reliability ICs for industrial, automotive, and lighting markets.
The LM3444 product line was engineered specifically for cost-sensitive, high-efficiency AC/DC LED drivers using passive PFC and non-isolated buck topology-targeting residential, commercial, and industrial solid-state lighting applications up to 150 W.
FAQ
What is the maximum LED string voltage supported by LM3444MM/NOPB?
The LM3444MM/NOPB itself does not impose a fixed maximum LED string voltage; instead, it regulates current based on VBUCK and inductor design. In practice, VBUCK derived from 277 VAC mains with valley-fill can reach ~380 V, allowing LED strings up to ~350 V (e.g., 100 LEDs @ 3.5 V). The actual limit depends on external MOSFET voltage rating and inductor saturation current. LM3444MM/NOPB's GATE driver and ISNS comparator operate independently of VLED magnitude.
Does LM3444MM/NOPB require an external microcontroller for dimming?
No, LM3444MM/NOPB supports standalone analog dimming via its FILTER pin, which accepts a DC voltage (0–750 mV) to linearly scale LED current from 0% to 100%. It also accepts filtered PWM signals without MCU involvement. No firmware, communication bus, or external DAC is needed-dimming is implemented entirely in analog hardware, simplifying certification and reducing bill-of-materials.
Can LM3444MM/NOPB be used with a single-stage valley-fill circuit?
Yes, LM3444MM/NOPB is explicitly designed to operate with single-, two-, or three-stage valley-fill PFC circuits. The datasheet confirms compatibility with all configurations, and Figure 9 shows single-stage implementation. VBUCK stability and hold-up time must be validated per stage count, but the controller's adaptive off-time architecture inherently accommodates the resulting VBUCK ripple profile without loop instability.
What is the purpose of the NC pins on LM3444MM/NOPB?
How does LM3444MM/NOPB achieve no-flicker operation at 120 Hz?
LM3444MM/NOPB achieves no-flicker operation by maintaining continuous conduction mode (CCM) across the entire AC half-cycle-even near voltage zero-crossings-through adaptive off-time control and valley-fill energy storage. The valley-fill capacitors sustain VBUCK above the LED string forward voltage during low-line periods, while the controller's 125 ns leading-edge blanking and fast current-loop response prevent discontinuous transitions. This eliminates 100/120 Hz current modulation, meeting IEC TR 61547-1 flicker immunity requirements without post-regulation filtering. LM3444MM/NOPB's behavior is verified in Figure 2 (efficiency vs. line voltage) and Section 7.3.5.
LM3444MM/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Packaging:
- Tape & Reel (TR)
- 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:
- 10-VSSOP
LM3444MM/NOPB FAQ
1.How can I place an order for LM3444MM/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3444MM/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 LM3444MM/NOPB reliable?
The price and inventory of LM3444MM/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3444MM/NOPB is usually 5 days.
3.What payment methods are accepted for LM3444MM/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3444MM/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3444MM/NOPB?
LM3444MM/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3444MM/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 LM3444MM/NOPB?
For technical support, including LM3444MM/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3444MM/NOPB requirements.
6.How does Aetrix verify that LM3444MM/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3444MM/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 LM3444MM/NOPB meets industry standards.
7.What is the process for return or replacement of LM3444MM/NOPB?
All LM3444MM/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3444MM/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 LM3444MM/NOPB part is unused and in its original packaging.
Return procedure for LM3444MM/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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