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Texas Instruments LM3497MM/NOPB
- Part No.:
- LM3497MM/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 10-TFSOP, 10-MSOP (0.118", 3.00mm Width)
- Datasheet:
-
LM3497MM/NOPB.pdf
- Description:
- IC LED DRIVER OFFL TRIAC 10VSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:1,924
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Product details
Overview
LM3497MM/NOPB from Texas Instruments (formerly National Semiconductor) is a triac-dimmable offline AC/DC buck constant-current LED driver controller with integrated triac dim decoder, bleeder circuit, and adaptive constant off-time regulation. It delivers >1A LED current across 80–277VAC input, supports flicker-free dimming from 45° to 135° conduction angle, and operates in MSOP-10 package for compact retrofit lighting designs.
For engineers reviewing the LM3497MM/NOPB datasheet, LM3497MM/NOPB pinout, LM3497MM/NOPB application, or LM3497MM/NOPB equivalent, key selection criteria include triac compatibility, passive PFC capability, 5.85 kHz internal ramp frequency, thermal shutdown at 165°C, and support for master/slave dimming coordination across multiple LED drivers.
Technical Context
The LM3497MM/NOPB implements a proprietary adaptive constant off-time control architecture where off-time is set by external R–C on COFF pin, while on-time-and thus switching frequency-varies inversely with VBUCK to maintain constant LED current. Its triac dim decoder uses BLDR pin sensing, ASNS PWM generation, FLTR1 ramp comparison, and FLTR2 filtered DC reference to translate firing angle into precise current control.
It integrates dual-stage functionality: line-sensing via bleeder-enabled angle detection (7.21V threshold on BLDR), and buck regulation using ISNS current sensing against FLTR2 voltage (720–780 mV), with GATE driving external MOSFETs at up to 0.88A sink/0.77A source peak. Thermal shutdown engages at 165°C with 20°C hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Input Voltage Range | 80–277VAC mains-compatible via valley-fill rectification and bleeder-assisted triac firing |
| LED Output Current | >1A constant current, set by ISNS sense resistor and FLTR2 reference (720–780 mV) |
| Dimming Range | 0–100% via 45°–135° conduction angle decoding; no 120Hz flicker due to valley-fill + DC dim reference |
| Switching Control | Adaptive constant off-time; off-time programmable via COFF pin; typical fRAMP = 5.85 kHz |
| Thermal Protection | Auto-shutdown at 165°C junction temperature; resumes at ~145°C; RθJA = 121°C/W (MSOP-10) |
| Supply & UVLO | VCC operating range: 8.0–12V; UVLO rising threshold 7.4–7.7V with 1V hysteresis |
| Bleeder Resistance | 230–325Ω (switched) on BLDR pin to ensure triac holding current during low-voltage phase |
Pinout & Package
LM3497MM/NOPB is housed in a 10-pin MSOP package (NS Package Number MUB10A, top mark SZBB), optimized for high-density LED driver PCB layouts with exposed thermal pad.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| ASNS | Triac dim decoder PWM output | 0–4V PWM signal proportional to triac on-time; feeds FLTR1 through RC filter |
| FLTR1 | Dim decoder ramp comparator input | Accepts filtered ASNS; tied to VCC (>4.9V) disables dim decoder for master/slave mode |
| DIM | Dim control I/O | Accepts external PWM or outputs synchronized dim signal to other LM3497s |
| COFF | Constant off-time setting | External R–C network sets fixed off-time; determines switching frequency vs. VBUCK |
| FLTR2 | Dim reference input to PWM comparator | DC voltage (720–780 mV) derived from dim decoder; sets peak LED current |
| GND | Circuit ground reference | Common return for ISNS, VCC, GATE, and internal comparators |
| ISNS | Current sense input | Monitors voltage across external sense resistor; triggers GATE turn-off when threshold reached |
| GATE | MOSFET gate driver output | Drives external N-channel MOSFET; 0.22–0.50V saturation, ±0.77A/±0.88A peak drive |
| VCC | Internal supply input | 8–12V bias rail; powers control logic and gate driver; includes UVLO protection |
| BLDR | Triac angle detection input | Senses rectified line via external pass regulator; 7.21V comparator threshold enables bleeder activation |
Key Features
| Feature | Design Value |
|---|---|
| Triac dim decoder with angle detection | Enables seamless 0–100% dimming using standard forward/reverse-phase dimmers without microcontroller |
| Integrated bleeder circuit | Switched 230Ω path ensures reliable triac firing at low conduction angles, eliminating pop-on/pop-off |
| Passive PFC via valley-fill topology | Draws current over >80% of AC cycle; achieves high power factor without active PFC IC or inductor |
| No 120Hz LED flicker | Valley-fill hold-up + DC dim reference eliminates perceptible flicker even at lowest dim levels |
| Master/slave dim coordination | Single DIM pin interconnection allows synchronized dimming across multiple LM3497MM/NOPB drivers |
Applications
| Retrofit LED Lamps | Commercial Downlights |
|---|---|
Use Scenario: Replacing incandescent A19 or PAR30 bulbs in existing wall-dimmer-controlled fixtures. IC Role / Device Role / Timing Role: Triac-dimmable AC/DC buck controller providing constant current to high-power LED strings while emulating resistive load behavior. Use Value: Eliminates need for external dimmer interface ICs; maintains full dim range and smooth fade-to-black with legacy dimmers. | Use Scenario: Multi-head recessed downlight systems in office ceilings controlled by central triac dimmer panels. IC Role / Device Role / Timing Role: Primary buck controller in each head, synchronized via DIM pin to ensure uniform brightness and dimming response. Use Value: Enables consistent color and intensity across dozens of fixtures without individual calibration or digital bus wiring. |
| Industrial High-Bay Lighting | Residential Track Lighting |
Use Scenario: 100–200W LED high-bay fixtures in warehouses with 277VAC line voltage and industrial-grade triac dimmers. IC Role / Device Role / Timing Role: Offline constant-current controller supporting wide-input (80–277VAC), high-current (>1A), and thermal robustness (125°C TJ). Use Value: Delivers stable light output despite voltage sags and ambient temperature swings; meets UL Class 2 and IEC 61347 safety requirements. | Use Scenario: Adjustable track heads in living rooms/kitchens using standard residential 120VAC triac dimmers. IC Role / Device Role / Timing Role: Compact MSOP-10 buck controller enabling low-profile driver integration inside narrow track head housings. Use Value: Achieves flicker-free dimming down to 1% with zero audible noise-critical for quiet residential environments. |
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 |
|---|---|---|---|
| ON Semiconductor NCL30000 | Fixed-frequency CCM buck controller; requires external triac decoder; no integrated bleeder | Lacks native triac decode and bleeder; needs additional components for dimmer compatibility | Choose when designing for cost-sensitive, non-retrofit applications where external decode is acceptable |
| Diodes Incorporated AL1676 | Primary-side regulated flyback controller with integrated triac decoder; no buck topology | Supports isolated output but lower efficiency and higher EMI than buck; limited to <750mA | Prefer for applications requiring reinforced isolation or where space permits larger transformer-based design |
Compared with NCL30000 and AL1676, LM3497MM/NOPB uniquely combines triac decode, bleeder, and buck topology in one MSOP-10 package-enabling compact, high-efficiency, non-isolated retrofit drivers with full dimmer interoperability and no 120Hz flicker.
Availability
LM3497MM/NOPB is available at Aetrix Electronics and suitable for retrofit LED lamps, commercial downlights, and industrial high-bay lighting requiring stable component supply, long-lifecycle assurance, and triac-dimmer compatibility.
Supply support for LM3497MM/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 acquired National Semiconductor in 2011 and maintains its analog power portfolio, including LED driver ICs designed for energy-efficient solid-state lighting.
The LM3497 product line was developed specifically for triac-dimmable offline LED drivers-targeting residential, commercial, and industrial lighting retrofits where compatibility with legacy dimmers and flicker-free performance are mandatory.
FAQ
What is the primary function of the LM3497MM/NOPB in an LED lighting system?
The LM3497MM/NOPB serves as a triac-dimmable AC/DC buck constant-current controller that regulates LED string current while interpreting phase-cut dimmer signals. It integrates a triac dim decoder, bleeder circuit, and adaptive constant off-time regulation to deliver flicker-free dimming from 0–100% across 80–277VAC inputs. The LM3497MM/NOPB replaces discrete dimmer interface solutions with a single IC, simplifying design and ensuring compatibility with standard residential and commercial triac dimmers.
How does the LM3497MM/NOPB eliminate 120Hz LED flicker?
The LM3497MM/NOPB eliminates 120Hz flicker by combining a valley-fill rectifier circuit-which maintains VBUCK above LED forward voltage for most of the AC half-cycle-with a DC dimming reference generated by its internal dim decoder. Unlike controllers relying on raw rectified waveform sampling, the LM3497MM/NOPB produces a stable, ripple-free FLTR2 voltage (720–780 mV) that directly controls LED current. This ensures constant current delivery regardless of instantaneous line voltage, removing perceptible flicker even at minimum dim levels.
Can multiple LM3497MM/NOPB ICs be synchronized for uniform dimming across several LED fixtures?
Yes, LM3497MM/NOPB supports master/slave dimming coordination. One LM3497MM/NOPB is configured as master (FLTR1 tied to VCC to disable its dim decoder), while others operate as slaves (FLTR1 tied to VCC, DIM pins interconnected). The master's DIM pin drives all slaves simultaneously, ensuring identical dimming curves and timing across fixtures. This avoids visible brightness mismatches in multi-fixture installations like track lighting or recessed downlight arrays-without requiring digital communication buses or external microcontrollers.
What is the role of the BLDR pin on the LM3497MM/NOPB, and why is it critical for triac operation?
The BLDR pin on the LM3497MM/NOPB senses the rectified AC line voltage via an external pass regulator to detect triac firing angle. Its comparator (7.21V threshold) triggers the internal bleeder circuit-a switched 230Ω path-that supplies holding current to the triac during low-voltage portions of the AC cycle. Without this, many triacs fail to re-fire reliably at low dim levels, causing pop-on, drop-out, or unstable dimming. The LM3497MM/NOPB's integrated bleeder ensures robust triac operation across all dim settings and dimmer types.
Does the LM3497MM/NOPB require an external microcontroller to interpret triac dimmer signals?
No, the LM3497MM/NOPB contains a fully integrated triac dim decoder with dedicated circuitry-including ASNS PWM generation, FLTR1 ramp comparison, and FLTR2 filtering-that converts conduction angle into a precise DC current reference without any microcontroller involvement. This analog approach reduces BOM count, eliminates firmware development, and ensures deterministic real-time dimming response. The LM3497MM/NOPB is designed for standalone operation in cost-sensitive, high-volume LED driver applications where simplicity and reliability are paramount.
LM3497MM/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:
- -
- Dimming:
- Triac
- Applications:
- Lighting
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-VSSOP
LM3497MM/NOPB FAQ
1.How can I place an order for LM3497MM/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3497MM/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 LM3497MM/NOPB reliable?
The price and inventory of LM3497MM/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3497MM/NOPB is usually 5 days.
3.What payment methods are accepted for LM3497MM/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3497MM/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3497MM/NOPB?
LM3497MM/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3497MM/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 LM3497MM/NOPB?
For technical support, including LM3497MM/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3497MM/NOPB requirements.
6.How does Aetrix verify that LM3497MM/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3497MM/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 LM3497MM/NOPB meets industry standards.
7.What is the process for return or replacement of LM3497MM/NOPB?
All LM3497MM/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3497MM/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 LM3497MM/NOPB part is unused and in its original packaging.
Return procedure for LM3497MM/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3497MM/NOPB Tags
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BCR402RE6327HTSA1
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BCR430UXTSA2
Infineon Technologies
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BCR420UE6433HTMA1
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BCR420UE6327HTSA1
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BCR421UE6327HTSA1
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LYT1604D-TL
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HV9910CLG-G
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CL2N8-G
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BCR420UW6-7
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BCR420UFD-7
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BCR421UFD-7
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