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Texas Instruments LM3450MTX/NOPB
- Part No.:
- LM3450MTX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM3450MTX/NOPB.pdf
- Description:
- IC LED DRVR OFFL ANALOG 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,638
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Product details
Overview
LM3450MTX/NOPB from Texas Instruments is a critical conduction mode (CRM) power factor controller with integrated phase dimming decoder, designed for isolated flyback LED drivers. It delivers active PFC with >0.95 power factor, 70:1 decoded PWM dimming output at 180–700 Hz, and supports 10–100W AC-input LED loads with analog and triac-based dimming compatibility.
For engineers reviewing the LM3450MTX/NOPB datasheet, LM3450MTX/NOPB pinout, LM3450MTX/NOPB application, or LM3450MTX/NOPB equivalent, this device is selected for dimmable offline LED driver designs requiring combined PFC regulation and accurate phase-angle decoding - especially in 120V/230V two-stage architectures under 15W/25W output where dynamic hold sampling optimizes efficiency.
Technical Context
The LM3450MTX/NOPB implements CRM PFC control using zero-crossing detection (ZCD) to terminate off-time and regulate output voltage while shaping sinusoidal input current. Its multiplier circuit accepts VAC (sampled rectified line) and COMP (error amplifier output) to generate a variable peak current threshold, enabling near-unity power factor without external feedforward compensation.
The phase dimming decoder samples VAC angle synchronously, applies dual-pole filtering (FLT1/FLT2), and remaps input phase to a 500 Hz PWM output (DIM pin) with programmable dimming range via VADJ. Dynamic hold current is sampled-not continuous-reducing standby loss while preventing triac misfire during decoding windows.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Operating Range | 8.5 V to 20 V - powers internal bias regulators and gate driver; UVLO thresholds at 12.2 V (enable) and 7.9 V (disable) |
| PFC Mode | Critical Conduction Mode (CRM) - enables zero-current switching for high efficiency and low EMI in flyback/boost topologies |
| DIM Output Frequency | 180–700 Hz - provides decoded PWM signal compatible with downstream LED driver dim inputs; nominal 500 Hz |
| FB Reference Voltage | 2.43–2.57 V - sets regulated output voltage in non-isolated designs via resistor divider; includes OVP shutdown at 1.22×VFB |
| CS Current Limit Threshold | 1.40–1.60 V - defines maximum sensed current before immediate GATE turn-off; protects MOSFET and transformer during overload |
| Junction Temperature Range | −40°C to +125°C - specifies full operational reliability across industrial and outdoor lighting environments |
| Thermal Resistance θJA | 38.0 °C/W (TSSOP-16) - determines maximum ambient temperature derating for sustained 100W operation on standard PCBs |
Pinout & Package
LM3450MTX/NOPB is housed in a 16-pin TSSOP package (Package Number PW), thermally optimized for surface-mount assembly in compact LED driver modules.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 VREF | 3V Precision Reference Output | Stable 2.85–3.15 V reference for external biasing and VADJ scaling; supplies 1.5–3.0 mA load capability |
| 2 VADJ | Analog Dimming & Range Control Input | Programs dimming range (0–100%) or enables low-power mode when pulled to GND; 56–75 mV threshold |
| 3 FLT2 | Second-Order Filter Input | Connects to capacitor to GND to set second filter pole for smooth phase-angle decoding |
| 4 FLT1 | First-Order Filter Input | Connects to series RC network to establish first filter pole; shapes dimmer angle response |
| 5 DIM | Open-Drain PWM Dim Output | Delivers 500 Hz PWM signal directly or via optocoupler to secondary-stage LED driver dim input |
| 6 VAC | Rectified AC Line Sampling Input | Accepts resistor-divider voltage from bridge output; 0–5.5 V dynamic range with 334–378 mV detection threshold |
| 7 COMP | Error Amplifier Output / PWM Comparator Input | Drives multiplier; compensated via external capacitor to GND; 69–161 µS transconductance |
| 8 FB | Inverting Feedback Input | Regulates output voltage to 2.5 V; bypassed with 5.11 kΩ to GND in isolated flyback configurations |
| 9 ISEN | Input Current Sense Input | Senses diode bridge return current for dynamic hold; references 162–232 mV threshold |
| 10 GND | Power Ground | Common reference for all analog and power circuits; must be low-impedance plane |
| 11 CS | MOSFET Source Current Sense | Monitors PFC switch current; triggers GATE turn-off when exceeding 1.5 V threshold |
| 12 GATE | High-Current Gate Driver Output | Drives N-channel MOSFET gate with ±1.5 A peak; 10.5–11.5 V high-level drive at 200 mA sink |
| 13 VCC | Bias Supply Input | Accepts 8.5–20 V primary-side supply; includes 1.6 mA quiescent current and 625 µA shutdown current |
| 14 ZCD | Zero-Crossing Detector Input | Detects transformer demagnetization; 1.45–1.55 V threshold with 135 ns delay and 150–250 mV hysteresis |
| 15 HOLD | Dynamic Hold Control Output | Drives external pass-FET to inject holding current only during sampled decoding intervals |
| 16 BIAS | Pre-regulator Gate Bias Output | Provides startup assist to pass-FET gate; outputs 13.5–22.6 V depending on VCC state |
Key Features
| Feature | Design Value |
|---|---|
| Critical Conduction Mode PFC | Enables >0.95 power factor with zero-voltage switching in flyback/boost topologies; eliminates need for external feedforward |
| 70:1 Phase Dimming Decoding | Maps triac firing angle to precise 500 Hz PWM output with programmable range via VADJ; supports legacy wall dimmers |
| Sampled Dynamic Hold Circuit | Activates holding current only during VAC sampling windows - reduces standby loss vs. continuous hold in LM3450A |
| Integrated Dual-Pole Filtering (FLT1/FLT2) | Smooths dimmer angle transitions and rejects noise; enables flicker-free dimming across full 0–100% range |
| Start-Up Pre-Regulator Bias (BIAS) | Generates gate bias for external pass-FET during cold start; ensures reliable VCC ramp-up from rectified AC |
Applications
| Dimmable Indoor Troffers | Outdoor Area Lighting |
|---|---|
|
Use Scenario: Commercial office ceiling troffer retrofit with triac-dimmable LED modules operating from 120V AC. IC Role / Device Role / Timing Role: LM3450MTX/NOPB serves as primary-side PFC controller and phase decoder, regulating 48V/1.2A output while interpreting wall dimmer angle. Use Value: Eliminates separate PFC and dimming ICs; achieves >0.95 PF and smooth 1–100% dimming without secondary-side feedback complexity. |
Use Scenario: Streetlight driver with 230V AC input, 36V/2.5A output, and compatibility with leading-edge dimmers. IC Role / Device Role / Timing Role: LM3450MTX/NOPB performs CRM flyback PFC and decodes phase angle into 500 Hz PWM sent via optocoupler to secondary LED current controller. Use Value: Enables single-chip solution for Class C conducted EMI compliance and EN61000-3-2 harmonic limits in outdoor-rated enclosures. |
| Low-Power Bulb Replacements | Two-Stage Architectures |
|
Use Scenario: A19-form-factor smart bulb with 120V input, 12W output, and analog/PWM dimming interface. IC Role / Device Role / Timing Role: LM3450MTX/NOPB operates in low-power mode (VADJ = GND) with 42 µs off-time; manages PFC and generates analog-dimming-compatible DIM signal. Use Value: Reduces no-load consumption below 0.5 W while maintaining dimming fidelity and thermal safety in enclosed housings. |
Use Scenario: Two-stage LED driver: LM3450MTX/NOPB handles front-end PFC and dimming decode; secondary stage uses LM3409HV for constant-current LED regulation. IC Role / Device Role / Timing Role: LM3450MTX/NOPB isolates dimming intelligence on primary side; DIM pin drives optocoupler input to secondary controller. Use Value: Decouples safety isolation boundary from dimming control; simplifies certification and improves system-level EMI immunity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver PFC and dimming decoder applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3450AMTX/NOPB | Continuous dynamic hold circuit instead of sampled hold; higher standby current but eliminates triac misfire risk entirely | Preferred for 230V >25W or 120V >15W single-stage designs where hold current stability is critical | Select LM3450AMTX/NOPB when designing for higher-power single-stage LED drivers or where dimmer compatibility must be guaranteed across all legacy triac types. |
| UCC28064ADR | Dedicated CRM PFC controller only - no integrated phase dimming decoder; requires external microcontroller or analog circuit for dimming | Used in non-dimmable or digitally controlled systems; lacks native triac decoding and DIM PWM output | Choose UCC28064ADR when PFC performance is prioritized over dimming integration, or when digital dimming (e.g., DALI) replaces phase control. |
Compared with LM3450AMTX/NOPB, LM3450MTX/NOPB trades lower standby loss for conditional hold activation; versus UCC28064ADR, it adds complete dimming decode functionality but with fixed analog architecture - making it optimal for cost-sensitive, triac-dimmable AC/DC LED drivers under 25W.
Availability
LM3450MTX/NOPB is available at Aetrix Electronics and suitable for dimmable indoor troffers, outdoor area lighting, low-power bulb replacements, and two-stage LED driver architectures requiring stable component supply and long-term production continuity.
Supply support for LM3450MTX/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 decades of expertise in LED driver and power conversion IC design.
The LM3450MTX/NOPB belongs to TI's LED lighting controller product line, engineered specifically for integrated AC/DC dimmable LED drivers that combine active PFC and phase-dimming compatibility in a single chip.
FAQ
What is the primary function of the LM3450MTX/NOPB in an LED driver system?
The LM3450MTX/NOPB integrates two core functions: critical conduction mode (CRM) power factor correction for AC-input regulation and a phase-dimming decoder that converts triac firing angle into a 500 Hz PWM signal. It enables single-chip control of both input power quality and output light intensity in isolated flyback LED drivers - eliminating the need for separate PFC and dimming ICs in 10–100W applications.
How does the LM3450MTX/NOPB differ from the LM3450AMTX/NOPB?
The LM3450MTX/NOPB uses sampled dynamic hold current - activated only during VAC angle sampling - reducing standby power loss. In contrast, LM3450AMTX/NOPB employs continuous dynamic hold, ensuring absolute triac misfire immunity at the cost of higher quiescent current. This makes LM3450MTX/NOPB preferred for <15W (120V) or <25W (230V) two-stage designs where efficiency is prioritized.
Can the LM3450MTX/NOPB be used in non-isolated boost PFC topologies?
Yes, the LM3450MTX/NOPB supports non-isolated boost PFC configurations. In such designs, the FB pin connects to a resistor divider from the output bus to regulate voltage to 2.5 V, and the COMP pin drives the multiplier directly. The ZCD pin remains unused, and the GATE output drives the boost MOSFET - retaining full PFC functionality without requiring optical isolation.
What is the role of the FLT1 and FLT2 pins on the LM3450MTX/NOPB?
FLT1 and FLT2 implement a dual-pole filter network that conditions the VAC signal before phase-angle decoding. FLT1 sets the first filter pole with an external RC network; FLT2 adds a second pole via capacitor-to-GND. Together, they suppress noise and harmonics from triac dimmers, enabling smooth, flicker-free dimming transitions across the full 0–100% range in the LM3450MTX/NOPB.
Does the LM3450MTX/NOPB support analog dimming in addition to phase dimming?
Yes, the LM3450MTX/NOPB supports analog dimming via the VADJ pin. When VADJ is connected to a resistor divider from VREF, it scales the dimming range; when pulled to GND, it enters low-power mode with reduced off-time. This allows hybrid dimming schemes - e.g., coarse adjustment via wall dimmer and fine-tuning via DC voltage - all managed within the same LM3450MTX/NOPB device.
LM3450MTX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Type:
- AC DC Offline Switcher
- Topology:
- Flyback, Step-Up (Boost)
- Internal Switch(s):
- Yes
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 8.5V
- Voltage - Supply (Max):
- 20V
- Voltage - Output:
- 11.5V
- Current - Output / Channel:
- -
- Frequency:
- -
- Dimming:
- Analog
- Applications:
- -
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 16-TSSOP
LM3450MTX/NOPB FAQ
1.How can I place an order for LM3450MTX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3450MTX/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 LM3450MTX/NOPB reliable?
The price and inventory of LM3450MTX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3450MTX/NOPB is usually 5 days.
3.What payment methods are accepted for LM3450MTX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3450MTX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3450MTX/NOPB?
LM3450MTX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3450MTX/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 LM3450MTX/NOPB?
For technical support, including LM3450MTX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3450MTX/NOPB requirements.
6.How does Aetrix verify that LM3450MTX/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3450MTX/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 LM3450MTX/NOPB meets industry standards.
7.What is the process for return or replacement of LM3450MTX/NOPB?
All LM3450MTX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3450MTX/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 LM3450MTX/NOPB part is unused and in its original packaging.
Return procedure for LM3450MTX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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