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Texas Instruments LM3445MMX/NOPB
- Part No.:
- LM3445MMX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LM3445MMX/NOPB.pdf
- Description:
- IC LED DRIVER OFFL DIM 10VSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,666
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Product details
Overview
LM3445MMX/NOPB from Texas Instruments is a TRIAC-dimmable, adaptive constant off-time AC/DC buck LED driver controller supporting 80–277 VAC input, delivering >1 A constant LED current with no 120-Hz flicker, and integrating a patented bleeder circuit for reliable TRIAC firing in retrofit lighting applications.
For engineers reviewing the LM3445MMX/NOPB datasheet, LM3445MMX/NOPB pinout, LM3445MMX/NOPB application, or LM3445MMX/NOPB equivalent, key selection criteria include dimmer compatibility across forward/reverse-phase TRIACs, valley-fill PFC implementation, thermal shutdown behavior at 165°C, and COFF-based switching frequency control.
Technical Context
The LM3445MMX/NOPB implements an adaptive constant off-time control architecture where the COFF pin sets the minimum off-time via external RC network, enabling programmable switching frequency (e.g., ~200 kHz at 120 VAC with C11 = 2.2 nF, R3 = 348 kΩ). Its angle-detect circuit monitors BLDR voltage against a 7.21-V threshold to decode TRIAC conduction angle, generating a filtered ASNS PWM signal.
Dim decoding uses a 5.85-kHz internal ramp generator compared against the FLTR1 DC voltage (0–4 V), producing a duty-modulated GATE output that regulates LED current without low-frequency ripple. The integrated bleeder MOSFET (230 Ω typical) activates below 7.21 V on BLDR to supply TRIAC holding current, then disables above threshold to improve efficiency.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 80–277 VAC line-compatible; enables global mains operation without input reconfiguration. |
| LED Current Capability | Supports >1 A constant current via ISNS resistor sensing; full-scale threshold is 1.269 V (typical). |
| Switching Frequency | Adaptive, set by COFF pin; typical 200 kHz at 120 VAC - allows compact magnetics and EMI filtering. |
| Dimming Compatibility | Works with standard forward- and reverse-phase TRIAC dimmers; decodes conduction angles from 45° to 135°. |
| Thermal Protection | Thermal shutdown engages at 165°C (typical), with 20°C hysteresis - prevents permanent damage under overload. |
| Package | 10-pin VSSOP (3.0 × 3.0 mm); optimized for high-density LED driver PCB layouts. |
| Quiescent Current | 2.85 mA (typical) at VCC = 12 V - minimizes standby power loss in always-on lighting systems. |
Pinout & Package
LM3445MMX/NOPB is housed in a 10-pin Very Thin Shrink Small Outline Package (VSSOP) with 0.5-mm lead pitch and exposed thermal pad. Package dimensions are 3.00 mm × 3.00 mm × 0.90 mm (height), suitable for thermally constrained LED driver modules.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1 (ASNS) | PWM output of TRIAC dim decoder | 0–4 V PWM signal proportional to dimmer on-time; feeds FLTR1 filter stage. |
| 2 (FLTR1) | First-stage dimming filter input | Accepts ASNS PWM; compared against 5.85-kHz internal ramp to generate dimmed GATE drive. |
| 3 (FLTR2) | Second-stage dimming filter input | RC-filtered DC reference (0–750 mV) controlling peak LED current; sets analog dimming level. |
| 4 (COFF) | Constant off-time setting input | External RC network defines minimum off-time - directly determines switching frequency. |
| 5 (GND) | Circuit ground reference | Common return for ISNS, VCC, and internal comparators; requires low-impedance layout. |
| 6 (ISNS) | LED current sense input | Connects to MOSFET source; 1.269 V threshold sets max LED current (e.g., 1.27 V / 0.1 Ω = 12.7 A). |
| 7 (GATE) | MOSFET gate driver output | High-current push-pull driver (±0.77 A peak) for external N-channel buck switch; 0.5 V saturation. |
| 8 (BLDR) | TRIAC angle detection input | Monitors rectified line via external regulator; 7.21 V threshold triggers bleeder activation for TRIAC hold. |
| 9 (VCC) | Internal supply rail | 8–12 V regulated supply; UVLO rising/falling thresholds at 7.7 V / 6.4 V ensure stable startup. |
| 10 (DIM) | Multi-function dim interface | I/O pin: accepts external PWM or outputs synchronized dim signal to slave LM3445s for multi-string control. |
Key Features
| Feature | Design Value |
|---|---|
| No 120-Hz flicker | Valley-fill PFC circuit + high-frequency buck regulation eliminates perceptible light modulation at line frequency. |
| Adaptive off-time control | COFF pin enables precise, temperature-stable frequency tuning - maintains constant ripple current across line/load. |
| Integrated TRIAC bleeder | On-chip 230 Ω (typical) bleeder path ensures reliable dimmer firing at low brightness without external components. |
| Wide dimming range | 45°–135° conduction angle decoding supports 0.5 mA–full-scale LED current with seamless transition to headroom dimming. |
| Thermal shutdown with hysteresis | 165°C trip / 145°C release prevents thermal runaway while avoiding oscillation during transient overloads. |
Applications
| Retrofit Residential Lighting | Commercial Downlight Systems |
|---|---|
Use Scenario: Replacing incandescent A19 bulbs with LED equivalents in existing wall-dimmer circuits. IC Role / Device Role / Timing Role: LM3445MMX/NOPB acts as the TRIAC-dimming interface and constant-current buck controller, translating phase-cut AC into stable LED drive. Use Value: Enables drop-in replacement without rewiring; maintains compatibility with legacy ELV and leading-edge dimmers. |
Use Scenario: High-efficiency LED downlights in office ceilings powered from shared 120/277 VAC circuits. IC Role / Device Role / Timing Role: LM3445MMX/NOPB manages valley-fill PFC and adaptive buck regulation to sustain >90% efficiency across 80–277 VAC. Use Value: Delivers consistent lumen output and color point across universal input voltage, reducing BOM variants. |
| Industrial High-Bay Fixtures | Smart Building LED Modules |
Use Scenario: 100–200 W LED high-bay lights in warehouses with centralized TRIAC dimming panels. IC Role / Device Role / Timing Role: LM3445MMX/NOPB provides master dim control via DIM pin daisy-chaining to multiple slave drivers. Use Value: Synchronizes dimming across dozens of fixtures using single dimmer channel - eliminates inter-fixture brightness variance. |
Use Scenario: Networked LED modules requiring analog dimming input alongside digital control interfaces. IC Role / Device Role / Timing Role: LM3445MMX/NOPB accepts external PWM on DIM pin while maintaining internal TRIAC decoding for hybrid dimming modes. Use Value: Supports both legacy wall dimmers and modern building automation systems without hardware change. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar TRIAC-dimmable LED driver controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| NCP1083DR2G | Fixed-frequency (65 kHz) flyback controller; lacks adaptive off-time and integrated bleeder; requires external TRIAC interface. | Targeted at lower-power (<30 W), isolated designs; no native valley-fill support. | Choose when isolation is mandatory and dimmer compatibility can be implemented externally. |
| UCC28810DR | Active PFC + constant current buck combo; higher integration but fixed 50/60 Hz dimming sync; no COFF frequency tuning. | Designed for high-PF (>0.9), high-power (>50 W) commercial fixtures; larger solution size. | Prefer when power factor correction compliance is primary and TRIAC dimming is secondary. |
Compared with NCP1083DR2G and UCC28810DR, the LM3445MMX/NOPB uniquely combines adaptive off-time control, integrated bleeder, and valley-fill PFC in a 10-pin VSSOP - delivering superior dimmer interoperability and minimal external component count for non-isolated, retrofit-optimized LED drivers.
Availability
LM3445MMX/NOPB is available at Aetrix Electronics and suitable for retrofit residential lighting, commercial downlight systems, and industrial high-bay fixtures requiring stable component supply with long lifecycle assurance.
Supply support for LM3445MMX/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 ICs, with decades of expertise in lighting control and energy-efficient power conversion.
The LM3445MMX/NOPB belongs to TI's LED lighting controller product line, engineered specifically for TRIAC-dimmable, non-isolated AC/DC LED drivers targeting cost-sensitive, high-volume retrofit and commercial lighting applications.
FAQ
What is the maximum LED current supported by the LM3445MMX/NOPB?
The LM3445MMX/NOPB supports LED currents greater than 1 A through external MOSFET selection and ISNS resistor scaling. With a 1.269 V (typical) current-sense threshold and a 0.1 Ω sense resistor, LM3445MMX/NOPB delivers up to 12.7 A LED current - limited only by external component ratings and thermal design.
Does the LM3445MMX/NOPB require an external bleeder resistor?
No - the LM3445MMX/NOPB integrates a bleeder circuit with a 230 Ω (typical) on-resistance path activated automatically when BLDR voltage falls below 7.21 V. This eliminates the need for discrete bleeder resistors while ensuring reliable TRIAC firing across dimming levels.
How does the LM3445MMX/NOPB eliminate 120-Hz LED flicker?
The LM3445MMX/NOPB eliminates 120-Hz flicker by combining valley-fill passive PFC (which smooths input current draw) with high-frequency adaptive buck regulation (>100 kHz). This decouples LED current from line-frequency ripple, ensuring constant illumination independent of AC phase.
Can the LM3445MMX/NOPB operate with both leading-edge and trailing-edge TRIAC dimmers?
Yes - the LM3445MMX/NOPB's angle-detect circuit and wide conduction-angle decoding range (45°–135°) support both leading-edge (standard TRIAC) and trailing-edge (electronic) dimmers. Its dim decoder responds to relative on-time, not waveform polarity, enabling broad interoperability.
What package type is used for the LM3445MMX/NOPB?
The LM3445MMX/NOPB uses a 10-pin VSSOP (DGS) package measuring 3.00 mm × 3.00 mm × 0.90 mm. It features a thermal pad for enhanced heat dissipation and is RoHS-compliant and lead-free per the /NOPB suffix.
LM3445MMX/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):
- 12V
- Voltage - Output:
- -
- Current - Output / Channel:
- -
- Frequency:
- 30kHz ~ 1MHz
- Dimming:
- Triac
- Applications:
- Lighting
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-VSSOP
LM3445MMX/NOPB FAQ
1.How can I place an order for LM3445MMX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3445MMX/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 LM3445MMX/NOPB reliable?
The price and inventory of LM3445MMX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3445MMX/NOPB is usually 5 days.
3.What payment methods are accepted for LM3445MMX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3445MMX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3445MMX/NOPB?
LM3445MMX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3445MMX/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 LM3445MMX/NOPB?
For technical support, including LM3445MMX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3445MMX/NOPB requirements.
6.How does Aetrix verify that LM3445MMX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3445MMX/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 LM3445MMX/NOPB meets industry standards.
7.What is the process for return or replacement of LM3445MMX/NOPB?
All LM3445MMX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3445MMX/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 LM3445MMX/NOPB part is unused and in its original packaging.
Return procedure for LM3445MMX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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