LNK3202D
LinkSwitch-TN2 cost-effective buck converter IC for non-isolated designs up to 360mA
Product Overview
Description
The LNK3202D is a member of the LinkSwitch-TN2 family, designed for cost-effective non-isolated power supply applications.
This IC integrates a 725V power MOSFET and controller in a simple SO-8 package, enabling compact and low-cost designs for appliance and industrial applications.
The device supports buck, buck-boost, and flyback topologies, providing flexibility for various application requirements while maintaining excellent load and line regulation.
Product Series
LNK
Primary Application
Appliance power supplies
Key Features
- Integrated 725V power MOSFET
- Simple non-isolated design
- Supports buck, buck-boost, flyback
- Excellent load and line regulation
- Frequency jittering for low EMI
- Built-in protection features
Specifications
| Current Rating | Up to 360mA |
|---|---|
| Input Voltage | 85-265V AC |
| MOSFET Voltage | 725V |
| Switching Frequency | 66kHz |
| Standby Power | <50mW |
| Package | SO-8 |
Applications
Appliance power supplies
Electronic system design
Industrial controls
Industrial automation and control
Smart meter power
Electronic system design
IoT device power
Electronic system design
FAE Expert Insights
"LinkSwitch-TN2 is my go-to recommendation for cost-sensitive non-isolated power supplies. The LNK3202D offers an excellent balance of performance and cost for applications up to 360mA. What I particularly like is the flexibility to use buck, buck-boost, or flyback topologies depending on the output voltage requirements. For appliance applications where isolation is not required, this IC can significantly reduce BOM cost compared to isolated designs. The built-in frequency jittering helps meet EMI requirements without additional filtering components. I recommend using the SO-8 package for automated assembly and good thermal performance."
Cost-effective solution for non-isolated power supplies with flexible topology options
— David Wang, BeiLuo
Frequently Asked Questions
What topologies are supported by LinkSwitch-TN2?
LinkSwitch-TN2 supports three main topologies: 1) Buck converter - Most common topology for step-down applications where output voltage is less than input voltage. Provides the highest efficiency and simplest design. 2) Buck-boost converter - Used when output voltage can be higher or lower than input voltage, or when negative output is required. 3) Flyback converter - Isolated topology using a transformer for applications requiring galvanic isolation. The choice depends on the output voltage requirement and whether isolation is needed. Buck topology is recommended for non-isolated designs with output voltage significantly lower than input voltage.
Choose buck topology for simplest design and highest efficiency when isolation is not required and output voltage is lower than input.
How do I calculate the output current capability?
The output current capability of LinkSwitch-TN2 depends on several factors: 1) Device current rating - LNK3202D is rated for 360mA maximum, 2) Input voltage - higher input voltage allows higher output current, 3) Output voltage - lower output voltage allows higher output current, 4) Thermal conditions - adequate heatsinking is required for maximum current. Use the following formula as a starting point: Iout_max ≈ (Idevice × Vin_min × η) / Vout, where Idevice is the device current limit, Vin_min is minimum input voltage, η is estimated efficiency (typically 70-80% for buck), and Vout is output voltage. For accurate calculations, refer to the datasheet curves or use PI Expert software.
Use PI Expert software for accurate current capability calculations, or contact our FAE team for design assistance.
What is the EMI performance of LinkSwitch-TN2?
LinkSwitch-TN2 features excellent EMI performance due to several design features: 1) Frequency jittering - the switching frequency varies randomly to spread EMI spectrum and reduce peak emissions, 2) Soft-start - gradual current ramp at startup reduces inrush current and conducted EMI, 3) Controlled switching - optimized gate drive minimizes switching noise. Typical conducted EMI performance meets EN55022 Class B limits with minimal external filtering. For designs requiring very low EMI, additional input filtering may be needed. The frequency jittering feature is particularly effective for meeting EMI standards without costly filters.
LinkSwitch-TN2 typically meets EMI standards with minimal filtering. Contact our FAE team for EMI optimization if your application has strict requirements.
How do I select the inductor for LinkSwitch-TN2 buck design?
Inductor selection for LinkSwitch-TN2 buck designs involves several considerations: 1) Inductance value - typically 330μH to 1mH depending on output current and ripple requirements, 2) Current rating - inductor saturation current should be at least 1.5 times the peak device current, 3) Core material - ferrite cores are recommended for high-frequency operation, 4) DCR - lower DC resistance reduces conduction losses, 5) Size and cost - balance performance with space constraints. The datasheet provides recommended inductor values for common designs. For 360mA designs, a 470μH inductor with 0.5A saturation current is typically suitable. Always verify inductor temperature rise under maximum load conditions.
Start with datasheet recommendations and verify thermal performance. Contact our FAE team for inductor selection guidance for specific applications.
What are the thermal considerations for LinkSwitch-TN2?
Thermal management is important for reliable LinkSwitch-TN2 operation: 1) Junction temperature must not exceed 150°C under worst-case conditions, 2) SO-8 package thermal resistance is approximately 100°C/W junction-to-ambient without heatsinking, 3) Copper area on PCB acts as heatsink - larger copper area reduces thermal resistance, 4) At 360mA output with 85V input, device dissipation is approximately 0.5-0.8W depending on output voltage, 5) Recommended copper area is at least 50mm² for SO-8 package. For high ambient temperature applications or continuous maximum load operation, increase copper area or add external heatsinking. Always measure actual device temperature during prototype testing.
Provide adequate copper area for thermal management. Contact our FAE team for thermal design assistance for high-temperature applications.