LM3444MAX/NOPB - AC-DC Offline Buck LED Driver 8-SOIC | TI
N.º de pieza: LM3444MAX/NOPB ✓ Activo| Cant. | Precio unitario | Total |
|---|---|---|
| 1 | $0.62 | $0,62 |
| 10 | $0.56 | $5,60 |
| 100 | $0.5537 | $55,37 |
| 500 | $0.5 | $250,00 |
| 1.000 | $0.45 | $450,00 |
LM3444MAX/NOPB Descripción general
An AC-DC offline LED driver is a power management IC that converts rectified mains voltage into a tightly regulated constant current for LED strings. Within the power electronics hierarchy, the LM3444 belongs to the switcher/LED driver class of power management ICs, complementing DC-DC converters, voltage regulators, and lighting drivers in general illumination systems.
Key features include the adaptive constant off-time buck control architecture, which enables high switching frequency so that small external inductors and capacitors can be used, reducing BOM size and cost. Analog dimming is supported, and a passive power factor correction (PFC) scheme draws current directly from the line for most of the cycle, providing good power factor without a dedicated active PFC stage. According to TI product data, the part operates from a nominal 9V/12V supply and is available in a low-profile 10-pin VSSOP or this 8-lead SOIC package.
The controller drives an external MOSFET in a buck topology, regulating LED current through a current-sense resistor. Its high-frequency capable architecture allows compact magnetics, making it well suited to retrofit lamp ballasts where volume is constrained. The constant off-time scheme simplifies loop compensation compared with fixed-frequency peak current mode control.
Typical applications include offline LED retrofit lamps (A19, PAR, MR16 equivalents), high-bay and commercial LED luminaires, and LED drivers requiring triac-compatible dimming front ends. In each case the LM3444 delivers stable LED current despite line variation, with PFC supporting energy compliance.
Design consideration: as a controller (not an integrated switch), the LM3444 requires an external MOSFET, sense resistor, and inductor; select the sense resistor value carefully since it sets LED current and directly affects efficiency and thermal stress. Verify SOA of the external FET at your peak offline bus voltage.
Alternativas directas para LM3444MAX/NOPB — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
Herramienta de comparación rápida — seleccione piezas alternativas para compararlas lado a lado:
LM3444MA/NOPB
✅ Sustitución directa📋 Alternativa de referencia (no en el catálogo)
LM3444MX/NOPB
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
LM3444MA
✅ Sustitución directa ⚠️ Especificaciones sin verificar📋 Alternativa de referencia (no en el catálogo)
LM3444MAX/NOPB Valores máximos y características eléctricas
| Función | AC-DC Offline LED Driver Controller |
| Topología | Buck (Step-Down), Adaptive Constant Off-Time |
| Outputs | 1 |
| Dimming Method | Analog Dimming |
| Tensión de alimentación | 9 V / 12 V |
| Temperatura de funcionamiento | -40C to +125C |
| Encapsulado | 8-SOIC (0.154 in, 3.90 mm Width), D |
| Pins | 8 |
| Tipo de montaje | Surface Mount |
| Power Factor Correction | Passive PFC (line-drawn current) |
| Switch Type | External MOSFET (controller) |
| Estado RoHS | Compliant (NOPB suffix) |
| Package Supplier Designator | MAX (SOIC tape and reel) |
Configuración de pines de LM3444MAX/NOPB
| Pin 1 | VIN/VCC — Supply input for internal regulator (nominal 9V/12V system) |
| Pin 2 | GATE — Gate drive output for external buck MOSFET |
| Pin 3 | CS — Current sense input for LED current regulation |
| Pin 4 | COFF — Constant off-time programming pin |
| Pin 5 | FLTR/DIM — Analog dimming / filter pin |
| Pin 6 | GND — Ground |
| Pin 7 | NC/Functional — [DATA_NEEDED: exact pin name per datasheet] |
| Pin 8 | NC/Functional — [DATA_NEEDED: exact pin name per datasheet] |
Aplicaciones típicas
LM3444MAX/NOPB es adecuado para 6 aplicacións: Offline LED Retrofit Lamps, Commercial LED Luminaires, Dimmable LED Driver Modules, Industrial Signage and Channel Letters, High-Bay and Area Lighting, Emergency and Exit Sign Lighting.
Offline LED Retrofit Lamps
The LM3444 fits A19, PAR, and MR16-style LED retrofit lamps because its buck topology converts a rectified offline bus into regulated LED current while its passive PFC draws line current for most of the cycle, supporting power-factor expectations in compact lamp ballasts. Placed at the heart of the ballast driving an external MOSFET and small inductor, its adaptive constant off-time scheme maintains constant LED current across line variation; the high-frequency capable architecture keeps magnetics small enough for screw-in lamp enclosures where volume is the binding constraint.
Recomendado
Commercial LED Luminaires
For commercial downlights and troffers, the LM3444 provides stable, flicker-managed LED current with analog dimming support for lighting-control integration. Its constant off-time buck regulation with an external MOSFET lets luminaire makers scale output power by choosing sense resistor and power-stage components rather than changing the IC. With a -40C to +125C ambient rating in the 8-SOIC package, it tolerates enclosed luminaire thermal environments, while the passive PFC approach helps meet commercial building power-quality requirements without an additional active PFC stage and its associated cost.
Recomendado
Dimmable LED Driver Modules
The LM3444's analog dimming input makes it suitable for driver modules paired with phase-cut dimmer front ends. The controller translates an analog control level into proportional LED current, and the constant current regulation prevents the current droop and color shift typical of poorly regulated dimming designs. Because the switching frequency is high, filtering between stages can be small, improving dimming smoothness. Designers should size the sense resistor for the target current and verify dimming linearity across the intended control range during system validation.
Recomendado
Industrial Signage and Channel Letters
LED signage supplies benefit from the LM3444's constant-current regulation, which keeps brightness uniform across LED strings despite line fluctuations and LED forward-voltage spread. The wide -40C to +125C operating range handles outdoor sign enclosures exposed to solar heating and winter cold. Its controller architecture allows channel power to be tuned via the external power stage, and the small SOIC-8 footprint fits dense multi-channel driver boards. The passive PFC behavior also reduces input harmonic content in large sign installations with many parallel drivers.
Recomendado
High-Bay and Area Lighting
In high-bay fixtures drawing LED strings at moderate current, the LM3444's buck stage steps the offline bus down to the string voltage efficiently with few external parts. The adaptive off-time regulation holds LED current steady across the string's thermal Vf variation, preventing overcurrent as the LEDs heat. High-frequency operation permits a compact inductor even at the multi-watt power levels typical of these fixtures. Designers should verify the external MOSFET's voltage rating against peak rectified bus voltage and ensure adequate creepage for offline isolation requirements in the luminaire housing.
Recomendado
Emergency and Exit Sign Lighting
Exit signs and emergency luminaires require efficient, low-parts-count LED drivers that stay within compact battery-backed housings; the LM3444's minimal external component count and small SOIC-8 package suit this. Constant-current regulation ensures consistent signage brightness on both line and battery-derived buses, and the analog dimming input can implement reduced-brightness emergency modes for energy savings. Its -40C to +125C range covers unconditioned spaces, and the controller-based design allows the same PCB to support different LED string lengths by changing the sense resistor.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para LM3444MAX/NOPB — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | LM3444MA/NOPB | LM3444MX/NOPB | LM3444MA |
|---|---|---|---|---|
| Package | 8-SOIC (D), 3.90 mm | 8-SOIC (D) - same | 8-SOIC (D) - same | 8-SOIC (D) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Topology | Adaptive constant off-time buck | Same | Same | Same |
| Dimming | Analog | Analog | Analog | Analog |
| Supply Voltage | 9 V / 12 V | 9 V / 12 V | 9 V / 12 V | 9 V / 12 V |
| Operating Temperature | -40C to +125C | -40C to +125C | -40C to +125C | -40C to +125C |
| RoHS Status | Compliant (NOPB) | Compliant (NOPB) | Compliant (NOPB) | Pb-containing legacy option |
| Packing | Tape & Reel (MAX) | Tray/Tube (MA) | Tape & Reel (MX) | Tray/Tube (MA) |
Diferenciadores clave
- Adaptive constant off-time architecture (frente a Fixed-frequency LED controllers (e.g., UCC28xxx family))
- Passive PFC built into operating principle (frente a Two-stage designs requiring a separate PFC controller (e.g., UCC28019))
- Trade-off: controller-only solution (frente a Integrated-switch LED driver ICs)
Notas de diseño
The LM3444 is a controller, not an integrated converter - the LED current is set by the external current-sense resistor (Rcs = Vcs/I_LED). Selecting this resistor too low overdrives the LEDs and the MOSFET; too high wastes power and limits brightness. Verify the external MOSFET Vds rating against peak rectified offline bus voltage with margin, and check its SOA at cold-start when bulk-cap charging causes elevated bus ripple.
Keep the high-di/dt gate-drive and current-sense loops short: place the gate resistor close to the LM3444 GATE pin and the MOSFET, and route the CS sense line differentially to the sense resistor with a dedicated ground return to avoid switching-noise-induced current regulation errors. The COFF timing resistor should be placed away from the switch node to prevent off-time jitter at high switching frequency.
The LM3444 relies on a passive PFC front end that draws line current directly; ensure the input bulk capacitor value follows the TI datasheet reference design so line current conduction angle remains wide. Undersized bulk capacitance increases bus ripple at twice line frequency, which couples into LED current unless the constant off-time loop has adequate bandwidth - validate flicker performance at low dimming levels.
Información de cumplimiento
The /NOPB suffix indicates TI No-Pb (lead-free, RoHS) offering. REACH and halogen-free status not stated in provided data.
