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Texas Instruments LM3450MT/NOPB
- Part No.:
- LM3450MT/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- LED Drivers
- Package:
- 16-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
LM3450MT/NOPB.pdf
- Description:
- IC LED DRVR OFFL ANALOG 16TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,811
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Product details
Overview
LM3450MT/NOPB from Texas Instruments is a dimmable LED driver IC with integrated active power factor correction (PFC) and phase-dimming decoder, operating in critical conduction mode (CRM), delivering 10–100W output, supporting 120V/230V AC inputs, and providing 500Hz PWM dimming output for isolated flyback topologies.
For engineers reviewing the LM3450MT/NOPB datasheet, LM3450MT/NOPB pinout, LM3450MT/NOPB application, or LM3450MT/NOPB equivalent, this page delivers verified technical context, confirmed pin functions, real-world dimming behavior, PFC performance boundaries, and validated alternative selection guidance for SSL driver design.
Technical Context
The LM3450MT/NOPB integrates two independent control subsystems: a CRM-based PFC controller using zero-crossing detection (ZCD) and current-mode sensing (CS), and a phase-angle decoder that samples VAC to generate a remapped 500Hz PWM output on DIM. Its error amplifier (FB/COMP) supports both isolated (bypassed via 5.11kΩ to GND) and non-isolated configurations.
Dynamic hold circuitry samples ISEN to inject holding current only during decoding windows-reducing standby loss-while the LM3450A variant operates continuously. The device features programmable analog dimming via VADJ, dual-pole filtering (FLT1/FLT2), and thermal shutdown at 160°C with 20°C hysteresis.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Operating Range | 8.5V to 20V - powers internal regulators and gate driver; UVLO rising threshold at 13.0V ensures reliable startup after bias supply stabilization. |
| PFC Mode | Critical Conduction Mode (CRM) - enables near-zero-voltage switching for high efficiency and low EMI in flyback/boost topologies. |
| DIM Output Frequency | 180–700Hz (typ. 500Hz) - provides decoded phase-dimming signal compatible with secondary-stage LED drivers requiring PWM dimming input. |
| FB Reference Voltage | 2.43–2.57V - sets regulated output voltage accuracy in non-isolated designs; used with resistor divider for precise PFC voltage loop control. |
| CS Current Limit Threshold | 1.40–1.60V - defines peak current limit for PFC switch; combined with sense resistor value determines maximum input power capability. |
| Junction Temperature Range | −40°C to +125°C - specifies full operational range for industrial and outdoor SSL applications with ambient derating per θJA = 38.0°C/W. |
| VREF Output | 2.85–3.15V @ no load - supplies stable 3V reference for external circuitry (e.g., VADJ divider, optocoupler bias); limited to 2.0mA max sink/source. |
Pinout & Package
LM3450MT/NOPB is housed in a 16-lead TSSOP package (Package Number PW), thermally optimized for surface-mount assembly in compact LED driver PCBs with moderate power dissipation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 VREF | Reference Output | 3V precision reference; connects directly to VADJ or external resistor divider for analog dimming calibration. |
| 2 VADJ | Analog Adjust Input | Sets dimming range: tied to GND for low-power mode, to VREF for standard 70% phase range, or to resistor divider for extended compatibility. |
| 3 FLT2 | Second Filter Pole | Connects series RC network to GND; establishes second-order filtering for smooth angle decoding and reduced flicker. |
| 4 FLT1 | First Filter Pole | Connects series RC network to GND; forms primary filter stage for VAC sampling, improving noise immunity on phase-dimming inputs. |
| 5 DIM | PWM Dimming Output | Open-drain 500Hz PWM output; drives optocoupler or secondary-stage dimming input directly-no level-shifting required. |
| 6 VAC | Rectified Line Sampling | Accepts resistor-divided rectified AC; detects phase angle for triac dimmer decoding with 356mV typical detection threshold. |
| 7 COMP | Error Amplifier Output | Drives multiplier input; compensation capacitor to GND sets loop stability; pre-biased at startup to ensure reliable PFC initiation. |
| 8 FB | Feedback Input | Inverting input of error amp; connected to output voltage divider in non-isolated designs; shorted to GND via 5.11kΩ for isolated flyback. |
| 9 ISEN | Input Current Sense | Non-inverting input for dynamic hold; senses bridge return current to trigger hold current injection when line current falls below threshold. |
| 10 GND | Power Ground | Common return for all analog and power circuits; must be low-impedance plane to minimize noise coupling into sensitive analog nodes. |
| 11 CS | Current Sense Input | Monitors PFC MOSFET source voltage; compares against multiplier output to terminate on-time; includes 140ns leading-edge blanking. |
| 12 GATE | MOSFET Gate Driver | 11.5V min high-level drive at 20mA; ±1.5A peak current capability; pull-down resistance 2–8Ω ensures fast turn-off of external PFC switch. |
| 13 VCC | Bias Supply Input | Accepts 8.5–20V primary-side bias; internal UVLO prevents operation outside safe range; bypass capacitor mandatory for stability. |
| 14 ZCD | Zero-Crossing Detector | Detects transformer demagnetization; connected via 100kΩ resistor to auxiliary winding; triggers new on-time after energy transfer completes. |
| 15 HOLD | Dynamic Hold Control | Open-drain output driving hold FET gate; activates only during sampled decoding windows to minimize standby power loss. |
| 16 BIAS | Pre-regulator Gate Bias | Drives pass-FET gate during startup; high-voltage output (18.8–22.6V) enables reliable initial charging of VCC from rectified AC. |
Key Features
| Feature | Design Value |
|---|---|
| Critical Conduction Mode (CRM) PFC | Enables >0.95 power factor across 10–100W loads without bulky input capacitors; reduces EMI and improves efficiency vs. CCM. |
| Phase-Dimming Decoder with Programmable Mapping | Remaps triac firing angle to 500Hz PWM output; VADJ pin allows extension beyond standard 70% dimming range for legacy dimmer compatibility. |
| Dynamic Hold Sampling | Activates hold current only during decoding windows-reducing average hold power by >50% vs. continuous hold-critical for <15W 120V designs. |
| Integrated Dual-Pole Filtering (FLT1/FLT2) | Eliminates high-frequency noise from phase-dimming inputs while preserving dimming resolution; enables smooth transitions without step artifacts. |
| Isolated Flyback Support via FB Bypass | 5.11kΩ resistor from FB to GND disables internal error amplifier and engages COMP pull-up, enabling seamless integration with optocoupler feedback loops. |
Applications
| Dimmable Indoor Downlights | Outdoor Area Lighting |
|---|---|
|
Use Scenario: 30W recessed downlight operating from 120V AC with trailing-edge triac dimmer in residential kitchens. IC Role / Device Role / Timing Role: LM3450MT/NOPB serves as primary-stage PFC controller and phase-decoder, generating isolated 500Hz PWM for secondary constant-current LED driver. Use Value: Achieves >0.97 PF and THD <15% while maintaining smooth 1%–100% dimming without audible noise or flicker. |
Use Scenario: 75W wall-mounted area light powered from 230V AC with leading-edge dimmer in commercial parking lots. IC Role / Device Role / Timing Role: LM3450MT/NOPB implements CRM flyback PFC and decodes phase angle to drive external LED driver IC via optocoupler-isolated DIM signal. Use Value: Enables single-stage architecture with 160°C thermal shutdown protection and robust hold current management for cold-start reliability. |
| Large-Form-Factor Smart Bulbs | Industrial Troffer Retrofit Kits |
|
Use Scenario: A21-size smart bulb with integrated Wi-Fi module requiring compact, thermally efficient 18W driver with phase-dimming support. IC Role / Device Role / Timing Role: LM3450MT/NOPB provides PFC regulation and generates DIM signal for secondary buck driver; VADJ configured for extended dimming range. Use Value: Reduces component count by integrating PFC + decoder, while low-power mode (VADJ-to-GND) cuts standby consumption to <0.5W. |
Use Scenario: 4-ft LED troffer retrofit operating from 277V AC with 0–10V + phase-dimming dual-input requirement in office buildings. IC Role / Device Role / Timing Role: LM3450MT/NOPB handles AC-phase decoding and PFC; its DIM output interfaces with analog-dimming-capable secondary controller. Use Value: Supports hybrid dimming schemes with seamless transition between 0–10V and phase inputs; thermal derating managed via θJA = 38.0°C/W layout guidance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver PFC + dimming decoder applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LM3450AMT/NOPB | Continuous dynamic hold circuit instead of sampled hold; higher standby current but eliminates misfire risk in high-capacitance 230V designs. | Preferred for 230V >25W or 120V >15W single-stage designs where hold reliability outweighs efficiency trade-off. | Select LM3450AMT/NOPB when designing for universal input >25W or when optical isolation is omitted and hold stability is critical. |
| UCC28064ADR | Dedicated CRM PFC controller only-no integrated phase decoder; requires external microcontroller or analog circuit for dimming interface. | Suitable for non-dimmable or digitally controlled systems; lacks native 500Hz PWM output and VAC sampling circuitry. | Choose UCC28064ADR only if dimming is handled externally and higher PFC precision (±0.5% VREF) justifies added system complexity. |
Compared with LM3450AMT/NOPB, the LM3450MT/NOPB reduces standby power by disabling hold between samples-ideal for low-power 120V designs-while UCC28064ADR offers tighter PFC regulation but forces external dimming implementation, increasing BOM count and firmware dependency.
Availability
LM3450MT/NOPB is available at Aetrix Electronics and suitable for dimmable LED lighting, indoor architectural lighting, and outdoor area lighting requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.
Supply support for LM3450MT/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 LM3450MT/NOPB belongs to TI's high-efficiency LED driver product line, engineered specifically for cost-sensitive, dimmable solid-state lighting applications requiring integrated PFC and phase-dimming decoding in a single chip.
FAQ
What is the primary function of the LM3450MT/NOPB in an LED driver system?
The LM3450MT/NOPB serves as a dual-function controller: it implements active power factor correction in critical conduction mode for input AC-DC conversion, and simultaneously decodes phase-dimming signals from triac dimmers to generate a 500Hz PWM output. In a typical two-stage LED driver, the LM3450MT/NOPB manages the primary-side PFC stage and communicates dimming intent to the secondary constant-current stage via the DIM pin-enabling fully compliant, flicker-free dimming without separate microcontroller intervention.
How does the dynamic hold circuit in the LM3450MT/NOPB differ from that in the LM3450AMT/NOPB?
The LM3450MT/NOPB uses a sampled dynamic hold circuit: it activates hold current only during specific decoding windows synchronized with VAC zero crossings, minimizing average power loss. In contrast, the LM3450AMT/NOPB maintains continuous hold current-ensuring zero misfire risk but increasing standby consumption. This distinction makes the LM3450MT/NOPB optimal for 120V designs under 15W and 230V designs under 25W, where efficiency is prioritized over absolute hold reliability.
Can the LM3450MT/NOPB support isolated flyback topologies, and how is feedback implemented?
Yes, the LM3450MT/NOPB fully supports isolated flyback topologies. Feedback is implemented by connecting a 5.11kΩ resistor from the FB pin to GND, which disables the internal error amplifier and engages a 5kΩ pull-up at COMP. The COMP pin then interfaces directly with the optocoupler's cathode on the secondary side, allowing the secondary-side error amplifier to regulate output voltage while the LM3450MT/NOPB handles PFC timing and dimming decoding on the primary side.
What is the role of the FLT1 and FLT2 pins, and how should they be configured?
The FLT1 and FLT2 pins implement a cascaded two-pole filter for the VAC input signal. FLT1 accepts a series RC network to ground to establish the first filter pole, suppressing high-frequency noise from triac dimmer commutation. FLT2 accepts a second RC network to ground, forming the second pole for enhanced attenuation of ringing and EMI. Proper configuration-typically 100kΩ + 1nF on FLT1 and 1MΩ + 100pF on FLT2-ensures accurate phase-angle detection while preventing false triggering during dimmer transitions.
Does the LM3450MT/NOPB require external components for startup, and what is the purpose of the BIAS pin?
Yes, the LM3450MT/NOPB relies on the BIAS pin for startup assistance. During initial power-up, the BIAS pin delivers a regulated high-voltage gate drive (18.8–22.6V) to a pass-FET connected between rectified AC and the VCC rail. This pre-regulator circuit rapidly charges the VCC bypass capacitor, enabling the controller to begin operation before the main PFC stage stabilizes-ensuring reliable startup even under low-line conditions or with large input capacitance.
LM3450MT/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 16-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tube
- 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
LM3450MT/NOPB FAQ
1.How can I place an order for LM3450MT/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LM3450MT/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 LM3450MT/NOPB reliable?
The price and inventory of LM3450MT/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LM3450MT/NOPB is usually 5 days.
3.What payment methods are accepted for LM3450MT/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LM3450MT/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LM3450MT/NOPB?
LM3450MT/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LM3450MT/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 LM3450MT/NOPB?
For technical support, including LM3450MT/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LM3450MT/NOPB requirements.
6.How does Aetrix verify that LM3450MT/NOPB is sourced from the original manufacturer or authorized distributors?
All LM3450MT/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 LM3450MT/NOPB meets industry standards.
7.What is the process for return or replacement of LM3450MT/NOPB?
All LM3450MT/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LM3450MT/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 LM3450MT/NOPB part is unused and in its original packaging.
Return procedure for LM3450MT/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
LM3450MT/NOPB Tags
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BCR402RE6327HTSA1
Infineon Technologies
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BCR430UXTSA2
Infineon Technologies
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BCR420UE6433HTMA1
Infineon Technologies
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BCR420UE6327HTSA1
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BCR421UE6327HTSA1
Infineon Technologies
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LYT1604D-TL
Power Integrations
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HV9910CLG-G
Microchip Technology
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CL2N8-G
Microchip Technology
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BCR420UW6-7
Diodes Incorporated
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BCR421UW6-7
Diodes Incorporated
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BCR420UFD-7
Diodes Incorporated
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BCR421UFD-7
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