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NXP Semiconductors SSL5251T/1J
- Part No.:
- SSL5251T/1J
- Manufacturer:
- NXP Semiconductors
- Category:
- LED Drivers
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SSL5251T/1J.pdf
- Description:
- IC LED DRIVER OFFL TRIAC 8SO
- Quantity:
- Payment:
- Shipping:
Inventory:1,245
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Product details
Overview
SSL5251T/1J from NXP Semiconductors is a mains-dimmable buck-boost LED driver IC with integrated source-switch, designed for non-isolated LED lighting up to 25 W. It operates in Boundary Conduction Mode (BCM) with on-time control, delivers constant output current with ±3% typical accuracy, supports phase-cut dimming, and achieves up to 88% efficiency using low-cost off-the-shelf inductors.
For engineers reviewing the SSL5251T/1J datasheet, SSL5251T/1J pinout, SSL5251T/1J application, or SSL5251T/1J equivalent, key selection criteria include its 0.87 Ω RDS(on) at 25 °C, 15 V start-up voltage, 155 mV regulated ISNS reference, valley-switching capability, and full auto-recovery protection suite including OVP, OSP, OCP, UVLO, and OTP.
Technical Context
The SSL5251T/1J implements a source-switch BCM buck-boost topology with adaptive switching frequency, enabling optimized inductor sizing and EMI performance. Its valley detection circuit monitors DEMOVP to trigger zero-current switching, minimizing turn-on losses while maintaining stable regulation across line and load variations.
Dimming is achieved via analog modulation of the internal reference using the DIM pin (0–2 V range), directly scaling output current without external DACs. The IC starts directly from an external resistor-no capacitor charge pump or auxiliary supply required-reducing BOM count and simplifying VCC design.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC operating range | 9.9–16 V - powers IC without auxiliary winding; clamped at 16 V max to eliminate need for external Zener |
| RDS(on) (25 °C) | 0.87 Ω - enables high-efficiency source-switch operation with minimal conduction loss |
| Vstartup | 15 V typical - ensures reliable start-up from resistor-fed supply under varying mains conditions |
| Vintregd(max) on ISNS | 155 mV typical - sets precise LED current accuracy (±3%) via sense-resistor feedback |
| Max switching frequency | <25 kHz - enforced by toff(max) = 40 μs to avoid audible noise during low-mains operation |
| ICC(oper) | 180 μA typical - ultra-low quiescent current extends lifetime and reduces thermal stress |
| OVP threshold | 1.82 V on DEMOVP - accurate output overvoltage detection with 3-cycle fault confirmation to reject noise |
Pinout & Package
SSL5251T/1J is housed in an SO8 plastic surface-mounted package (SOT96-1), 4.9 × 6.0 × 1.75 mm, with standard 1.27 mm pitch and gull-wing leads.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| DEMOVP (1) | Demagnetization & OVP sensing | Detects valley for ZCS turn-on and monitors LED voltage via resistive divider for accurate OVP |
| GND (2) | Power and signal reference | Common return path for all internal circuits and external sense components |
| n.c. (3) | No connection | Internally unconnected; must remain floating per datasheet |
| SW (4) | Source-switch drain | High-side switch node connecting to inductor; rated for 22 V max and 2 A peak |
| ISNS (5) | Current sense input | Measures inductor current via external resistor; regulates on-time to maintain constant IOUT |
| VCC (6) | Supply voltage input | Accepts 9.9–16 V; includes internal clamp and UVLO (10 V threshold) with 5 V hysteresis |
| COMP (7) | Loop compensation | Provides error amplifier output for stability tuning; 2–4 V operating range with 4.8 V clamp |
| DIM (8) | Dimming control | Analog input (0–2 V) modulating internal reference; supports leading-edge and trailing-edge phase-cut dimmers |
Key Features
| Feature | Design Value |
|---|---|
| Valley-switching with DEMOVP | Reduces turn-on losses by triggering SW at inductor current zero-crossing, improving efficiency and EMI |
| Capacitor-free VCC start-up | Eliminates charge-pump capacitor and auxiliary winding, lowering cost and board space vs. transformer-fed controllers |
| Adaptive frequency in BCM | Enables use of smaller, lower-cost inductors while maintaining high efficiency (>85%) across 85–265 VAC input |
| Flicker-free phase-cut dimming | Combines deep dimming (down to 1%), fast transient response, and LEB filtering to suppress visible flicker |
| Auto-recovery protections | UVLO, cycle-by-cycle OCP, OTP, OVP, and OSP all reset automatically after fault removal-no latch-off or manual reset needed |
Applications
| Residential Dimmable LED Bulbs | Commercial LED Downlights |
|---|---|
Use Scenario: Retrofit A19 and GU10 LED lamps operating directly from 120/230 VAC mains with TRIAC dimmers. IC Role / Device Role / Timing Role: Primary controller managing buck-boost power stage, dimming interface, and safety-critical protections. Use Value: Enables compact single-layer PCB design with <25 W output, deep dimming, and flicker-free performance meeting ENERGY STAR requirements. | Use Scenario: Non-isolated LED drivers in recessed ceiling downlights for office and retail spaces. IC Role / Device Role / Timing Role: Constant-current regulator implementing BCM on-time control with adaptive frequency for optimal EMI and thermal behavior. Use Value: Delivers 88% efficiency and >0.9 PF without active PFC, reducing heatsink size and system cost while supporting legacy dimmer compatibility. |
| LED Tube Light Drivers | Smart Lighting Modules |
Use Scenario: T8/T5 LED tube replacements requiring direct AC line connection and TRIAC/ELV dimming support. IC Role / Device Role / Timing Role: Mains-connected buck-boost controller with integrated source-switch and valley detection for low-loss operation. Use Value: Achieves stable current regulation across wide input range (85–265 VAC) and eliminates need for Y-capacitors or isolation transformers. | Use Scenario: Integrated smart LED modules with microcontroller-based dimming interfaces (e.g., DALI-to-analog conversion). IC Role / Device Role / Timing Role: Analog dimming front-end translating MCU-generated DC voltage into precise LED current scaling. Use Value: DIM pin accepts 0–2 V analog input with 100 mV/V gain linearity, enabling seamless integration with digital control systems. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar LED driver controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| STLUX385A | Integrated 8-bit MCU + 3-channel LED controller; requires external MOSFET; higher BOM cost and design complexity | Targeted at multi-channel, digitally addressable lighting; not optimized for single-stage phase-dimmable bulbs | Choose STLUX385A only when programmable sequencing, communication (UART/I²C), or multi-string control is required |
| NCL30160 | Fixed-frequency CCM buck controller; no valley detection; lower efficiency (~82%) and higher EMI; requires auxiliary supply | Better suited for cost-sensitive non-dimmable applications; lacks deep dimming and flicker suppression features | Select NCL30160 for fixed-output, non-dimmable LED tubes where simplicity and lowest component count outweigh dimming performance |
Compared with STLUX385A and NCL30160, the SSL5251T/1J uniquely combines capacitor-free start-up, valley-switching BCM operation, and full auto-recovery protection in a single SO8 package-making it the optimal choice for compact, high-performance, phase-dimmable LED bulb designs up to 25 W.
Availability
SSL5251T/1J is available at Aetrix Electronics and suitable for residential LED retrofit bulbs, commercial downlights, LED tube drivers, and smart lighting modules requiring stable component supply and long-term production continuity.
Supply support for SSL5251T/1J 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
NXP Semiconductors is a global semiconductor company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and IoT applications.
The SSL5251T/1J belongs to NXP's SSL (Solid-State Lighting) controller family, engineered specifically for cost-effective, high-efficiency, mains-dimmable LED drivers targeting non-isolated AC/DC topologies.
FAQ
What is the recommended inductor value for SSL5251T/1J in a 15 W, 230 VAC application?
The SSL5251T/1J does not fix inductance; its adaptive BCM frequency allows flexible inductor selection. For 15 W at 230 VAC, a 680 µH–1.2 mH shielded drum core inductor with ≤1.2 A saturation current is typical. Inductor size is optimized by balancing peak current ripple, efficiency, and EMI-refer to Figure 3 and Section 8.1 of the SSL5251T/1J datasheet for boundary condition calculations.
Does SSL5251T/1J support both leading-edge and trailing-edge dimmers?
Yes, the SSL5251T/1J supports both leading-edge (TRIAC) and trailing-edge (electronic low-voltage) dimmers via its analog DIM pin (0–2 V range). Its deep dimming capability (down to 1%), fast transient response, and built-in leading-edge blanking ensure flicker-free operation across dimmer types without external calibration.
How does SSL5251T/1J achieve capacitor-free VCC start-up?
The SSL5251T/1J uses an integrated source-switch topology that draws supply current directly from the external VCC resistor (RVCC)-no charge-pump capacitor or auxiliary winding needed. An internal clamp limits VCC to 16 V, and the 15 V start-up threshold ensures reliable initiation even with slow-rising mains voltage, eliminating lamp flicker during turn-on.
What protection features are implemented in SSL5251T/1J and how do they recover?
The SSL5251T/1J integrates UVLO, cycle-by-cycle OCP, internal OTP, OVP, and OSP-all with auto-recovery. For example, OVP triggers a controlled VCC discharge to 6.2 V, then restarts; OTP halts switching until junction temperature drops below 118 °C. No latch-off or external reset is required, ensuring robust operation in real-world lighting environments.
Can SSL5251T/1J be used in isolated flyback topologies?
No-the SSL5251T/1J is explicitly designed for non-isolated buck-boost topologies with a source-switch configuration. Its DEMOVP pin relies on direct inductor demagnetization detection, and its gate drive architecture is incompatible with transformer-coupled flyback operation. Use NXP's UCC28810 or similar isolated controllers for flyback-based designs.
SSL5251T/1J Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Discontinued at Digi-Key
- Type:
- AC DC Offline Switcher
- Topology:
- Step-Down (Buck), Step-Up (Boost)
- Internal Switch(s):
- No
- Number of Outputs:
- 1
- Voltage - Supply (Min):
- 9.9V
- Voltage - Supply (Max):
- 16V
- Voltage - Output:
- -
- Current - Output / Channel:
- -
- Frequency:
- -
- Dimming:
- Triac
- Applications:
- Lighting
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SO
SSL5251T/1J FAQ
1.How can I place an order for SSL5251T/1J through Aetrix?
Please submit a Request for Quotation (RFQ) for SSL5251T/1J 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 SSL5251T/1J reliable?
The price and inventory of SSL5251T/1J are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SSL5251T/1J is usually 5 days.
3.What payment methods are accepted for SSL5251T/1J?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SSL5251T/1J transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SSL5251T/1J?
SSL5251T/1J orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SSL5251T/1J 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 SSL5251T/1J?
For technical support, including SSL5251T/1J datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SSL5251T/1J requirements.
6.How does Aetrix verify that SSL5251T/1J is sourced from the original manufacturer or authorized distributors?
All SSL5251T/1J 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 SSL5251T/1J meets industry standards.
7.What is the process for return or replacement of SSL5251T/1J?
All SSL5251T/1J units undergo pre-shipment inspection (PSI). If there is an issue with SSL5251T/1J, 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 SSL5251T/1J part is unused and in its original packaging.
Return procedure for SSL5251T/1J:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SSL5251T/1J 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
Infineon Technologies
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BCR421UE6327HTSA1
Infineon Technologies
-
LYT1604D-TL
Power Integrations
-
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
Diodes Incorporated
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