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Texas Instruments LM3444MAX/NOPB
- Part No.:
- LM3444MAX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LM3444MAX/NOPB.pdf
- Description:
- IC LED DRIVER OFFL ANALOG 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,768
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Product details
Overview
LM3444MAX/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 integrated thermal shutdown. It enables high-efficiency, flicker-free solid-state lighting in residential and commercial fixtures using passive valley-fill PFC.
For engineers reviewing the LM3444MAX/NOPB datasheet, LM3444MAX/NOPB pinout, LM3444MAX/NOPB application, or LM3444MAX/NOPB equivalent, key selection criteria include its adaptive off-time architecture for ripple-current stability, COFF-programmable timing, GATE drive capability for external MOSFETs, and operation across wide ambient temperatures (−40°C to +125°C) without external compensation.
Technical Context
The LM3444MAX/NOPB implements a proprietary constant off-time control scheme where tOFF is set by external R/C on COFF, while tON varies inversely with VBUCK/VLED to maintain constant average LED current. Its ISNS comparator trips at 1.269 V (typ), enabling precise current regulation via sense resistor R3.
It integrates a valley-fill PFC interface-accepting rectified AC input-and drives an external buck-stage MOSFET via GATE with 0.5 V (max) low-side saturation. Thermal shutdown activates at 165°C (typ) with 20°C hysteresis, and UVLO ensures stable startup between 6.0 V and 7.7 V on VCC.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 80–277 VAC line voltage; supports global mains without transformer or active PFC stage |
| LED Current Capability | >1 A continuous; set by ISNS threshold (1.269 V typ) and external sense resistor |
| Switching Frequency Range | 30 kHz to >1 MHz; user-programmable via COFF pin RC network |
| GATE Drive Output | Capable of driving external N-channel MOSFET; 0.5 V max low-saturation voltage at 100 mA sink |
| Thermal Shutdown Threshold | 165°C (typ); disables GATE until junction cools to ~145°C, protecting against sustained overload |
| VCC Operating Range | 8–13 V; includes UVLO with 1.3 V hysteresis (6.4 V falling, 7.7 V rising) |
| ISNS Voltage Threshold | 1.269 V (typ); defines peak inductor current limit and sets average LED current in CCM |
Pinout & Package
LM3444MAX/NOPB is housed in a 10-pin VSSOP package (3.00 mm × 3.00 mm body, 0.5 mm pitch), optimized for compact LED driver PCB layouts with thermal pad exposure.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| COFF | Off-time programming input | Connects to RC network that sets constant tOFF; determines switching frequency and ripple current stability |
| FILTER | Analog/PWM dimming interface | Accepts DC voltage or filtered PWM signal to adjust LED current; internal 750 mV reference enables analog dimming |
| GATE | Power MOSFET gate driver output | Drives external N-channel buck switch; capable of 0.88 A peak sink current for fast turn-off |
| GND | Power and signal reference ground | Common return for ISNS, VCC, and gate drive; must be low-impedance to avoid current-sense error |
| ISNS | Current sense comparator input | Monitors voltage across external sense resistor; triggers GATE turn-off when ≥1.269 V (typ) |
| VCC | Internal bias supply output | Provides regulated power to internal circuitry and GATE driver; requires local 0.1 µF bypass capacitor |
| NC | No-connect terminal | Pins 1, 2, 3, and 10 are unconnected internally; must remain floating per datasheet |
Key Features
| Feature | Design Value |
|---|---|
| Adaptive constant off-time control | Maintains consistent LED current ripple across line voltage variations without loop compensation |
| Passive valley-fill PFC integration | Enables >0.9 power factor with simple diode-capacitor network; eliminates need for active PFC IC |
| No-flicker 120 Hz operation | Eliminates visible LED flicker under full-wave rectified AC input via continuous conduction mode control |
| Low quiescent current | 2.25 mA typical VCC supply current enables high efficiency even at light load |
| Integrated thermal protection | Auto-recovering shutdown prevents latch-up during overtemperature events; no external circuitry required |
Applications
| Residential LED Lamps | Commercial Downlights |
|---|---|
Use Scenario: Retrofit A19 and PAR30 LED bulbs operating directly from 120 VAC or 230 VAC mains. IC Role / Device Role / Timing Role: Constant-current buck controller managing external MOSFET and inductor to regulate LED string current independent of line variation. Use Value: Enables >85% system efficiency and flicker-free illumination using only passive PFC components and no electrolytic bulk capacitors. | Use Scenario: High-bay and troffer lighting fixtures requiring >1 A LED drive current and robust thermal performance. IC Role / Device Role / Timing Role: Primary current regulator in isolated or non-isolated buck topology; COFF pin allows frequency tuning to optimize EMI and magnetics size. Use Value: Supports 14-series LED strings at 24.5 V output with 95% peak efficiency and thermal shutdown at 165°C for long lifetime in enclosed fixtures. |
| Industrial Area Lighting | Outdoor Street Lighting |
Use Scenario: Harsh-environment warehouse lights exposed to −40°C to +85°C ambient with wide input voltage tolerance. IC Role / Device Role / Timing Role: Mains-connected LED driver controller ensuring stable current regulation despite voltage sags and surges. Use Value: Guaranteed operation from −40°C to +125°C junction temperature with UVLO hysteresis preventing erratic startup during brownouts. | Use Scenario: Pole-mounted LED streetlights powered from 277 VAC utility lines with outdoor-rated thermal management. IC Role / Device Role / Timing Role: Core timing and current control element in high-voltage buck converter; GATE drive supports 600 V MOSFETs with fast fall time. Use Value: Delivers >1 A output with <125 ns leading-edge blanking to reject noise from high-dV/dt switching in outdoor EMI environments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| UCC28810DR | Fixed-frequency CRM controller; requires external PFC stage; no COFF programmability | Better suited for higher-power (>30 W), tightly regulated constant-voltage + constant-current dual-output designs | Select UCC28810DR when needing CRM-based efficiency optimization above 50 W and integrated PFC enablement |
| NCP1075P | Fixed-frequency flyback controller; integrated 700 V MOSFET; no valley-fill support or adaptive off-time | Targeted at lower-cost, lower-power (<15 W) isolated LED drivers with basic regulation only | Select NCP1075P when isolation, BOM reduction, and cost are prioritized over flicker-free performance and high PF |
Compared with UCC28810DR and NCP1075P, the LM3444MAX/NOPB uniquely combines adaptive off-time control, valley-fill PFC compatibility, and flicker-free 120 Hz operation-making it optimal for non-isolated, high-PF, medium-power LED drivers where size, efficiency, and visual quality are critical.
Availability
LM3444MAX/NOPB is available at Aetrix Electronics and suitable for residential LED lamps, commercial downlights, and industrial area lighting requiring stable component supply, long-lifecycle availability, and traceable sourcing for production programs.
Supply support for LM3444MAX/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 specializing in analog, embedded processing, and power management technologies with over 50 years of innovation in energy-efficient electronics.
The LM3444MAX/NOPB belongs to TI's AC/DC LED driver controller product line, designed specifically for cost-sensitive, high-efficiency, non-isolated LED lighting systems operating directly from universal AC mains.
FAQ
What is the maximum LED current supported by the LM3444MAX/NOPB?
The LM3444MAX/NOPB supports LED currents greater than 1 A, determined by the ISNS pin threshold voltage (1.269 V typical) and the value of the external current-sense resistor. For example, a 1.2 Ω resistor yields ~1.06 A average LED current in continuous conduction mode. The device maintains regulation across line and load variations without external compensation.
Does the LM3444MAX/NOPB require an external MOSFET?
Yes, the LM3444MAX/NOPB is a controller-not an integrated switch-and requires an external N-channel MOSFET driven by its GATE pin. The GATE output provides up to 0.88 A peak sink current and 0.5 V max saturation voltage at 100 mA, enabling fast switching of discrete power FETs in buck topologies.
How does the LM3444MAX/NOPB achieve flicker-free operation at 120 Hz?
The LM3444MAX/NOPB achieves flicker-free operation by maintaining continuous conduction mode (CCM) across the entire AC half-cycle, enabled by its adaptive constant off-time architecture and valley-fill PFC input stage. This ensures uninterrupted LED current flow even during low-voltage portions of the rectified sine wave, eliminating 120 Hz intensity modulation.
Can the LM3444MAX/NOPB be used with a three-stage valley-fill circuit?
Yes, the LM3444MAX/NOPB is fully compatible with single-, two-, and three-stage valley-fill circuits. The datasheet confirms operation with all configurations, and the valley-fill network directly supplies VBUCK to the buck stage. Three-stage designs improve power factor and reduce hold-up capacitance requirements compared to two-stage variants.
What is the purpose of the COFF pin on the LM3444MAX/NOPB?
The COFF pin on the LM3444MAX/NOPB sets the constant off-time duration via an external resistor and capacitor. This directly determines the switching frequency and stabilizes LED current ripple across input voltage changes. A typical configuration uses a 348 kΩ resistor and 2.2 nF capacitor to achieve ~200 kHz nominal frequency at 7-LED string operation.
LM3444MAX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm 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:
- 8-SOIC
LM3444MAX/NOPB FAQ
1.How can I place an order for LM3444MAX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3444MAX/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 LM3444MAX/NOPB reliable?
The price and inventory of LM3444MAX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3444MAX/NOPB is usually 5 days.
3.What payment methods are accepted for LM3444MAX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3444MAX/NOPB transactions.
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4.How is shipping managed for LM3444MAX/NOPB?
LM3444MAX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3444MAX/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 LM3444MAX/NOPB?
For technical support, including LM3444MAX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3444MAX/NOPB requirements.
6.How does Aetrix verify that LM3444MAX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3444MAX/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 LM3444MAX/NOPB meets industry standards.
7.What is the process for return or replacement of LM3444MAX/NOPB?
All LM3444MAX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3444MAX/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 LM3444MAX/NOPB part is unused and in its original packaging.
Return procedure for LM3444MAX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3444MAX/NOPB Tags
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