Contact Sales & After-Sales Service

Contact & Quotation

  • Inquire: Call 0086-755-23203480, or reach out via the form below/your sales contact to discuss our design, manufacturing, and assembly capabilities.
  • Quote: Email your PCB files to Sales@pcbsync.com (Preferred for large files) or submit online. We will contact you promptly. Please ensure your email is correct.
Drag & Drop Files, Choose Files to Upload You can upload up to 3 files.

Notes:
For PCB fabrication, we require PCB design file in Gerber RS-274X format (most preferred), *.PCB/DDB (Protel, inform your program version) format or *.BRD (Eagle) format. For PCB assembly, we require PCB design file in above mentioned format, drilling file and BOM. Click to download BOM template To avoid file missing, please include all files into one folder and compress it into .zip or .rar format.

Thermal Via Calculator - PCBsync

Thermal Via Calculator

PCBsync Engineering Tools
Heat Transfer
Input Parameters
Power Dissipation 1 W
Via Diameter 0.3 mm
Plating Thickness 25 µm
PCB Thickness 1.6 mm
Number of Vias 9
Via Fill
Max Junction Temp 125°C
Ambient Temperature 25°C
Calculated Results
Total Thermal Resistance
45.2
°C/W
Per Via: 407 °C/W
Temperature Rise 45.2°C
0°C 25°C 50°C 100°C
Junction Temp
70.2 °C
Thermal Margin
54.8 °C
Heat Flow
111 mW/via
Via Array Area
0.64 mm²
HEAT SOURCE HEAT FLOW 3×3 Array
Copper
FR4
Heat Gradient
Thermal design within safe limits
Recommendation
Current configuration provides adequate thermal performance. For improved heat dissipation, consider using copper-filled vias or increasing via count.
Via Specifications
9 vias × 0.3mm diameter with 25µm plating through 1.6mm PCB. Fill type: Air (hollow). Effective copper cross-section per via: 0.022 mm².

Understanding Thermal Via Design

Thermal vias provide a low-resistance path for heat to flow from a component through the PCB to heat-spreading layers or heatsinks. They are essential for power semiconductors, LEDs, and any component with an exposed thermal pad. Proper via design can reduce junction temperature by 20-40°C.

Rθ,via = L / (k × A)   where   A = π × (D × t - t²)   (hollow via)

Where L is PCB thickness, k is thermal conductivity (copper: 385 W/m·K), D is via diameter, and t is plating thickness. For filled vias, use full cross-sectional area. Multiple vias in parallel reduce total thermal resistance proportionally.

Via Fill Options
  • Air (Open) — Lowest cost, highest resistance
  • Solder filled — Moderate improvement (~40%)
  • Copper filled — Best performance (~3× better)
  • Conductive epoxy — Good balance of cost/performance
Typical Via Sizes
  • 0.2-0.3mm — Standard thermal vias
  • 0.4-0.5mm — Enhanced thermal performance
  • 0.6-0.8mm — High-power applications
  • 1.0mm+ — Maximum heat transfer
Layout Best Practices
  • Place vias directly under thermal pad
  • Use grid pattern (3×3, 4×4, 5×5)
  • Maintain 0.5-1.0mm pitch between vias
  • Connect to large copper pour on bottom
Thermal Conductivity Reference
  • Copper: 385 W/m·K
  • Solder (SAC305): 58 W/m·K
  • FR4: 0.3 W/m·K (through-plane)
  • Thermal epoxy: 1-10 W/m·K

Design Tip: The PCB itself (FR4) is a poor thermal conductor. Without thermal vias, heat must spread laterally through thin copper layers. Vias provide a direct vertical path with ~1000× better thermal conductivity than FR4, dramatically reducing thermal resistance.

Contact Sales & After-Sales Service

Contact & Quotation

  • Inquire: Call 0086-755-23203480, or reach out via the form below/your sales contact to discuss our design, manufacturing, and assembly capabilities.

  • Quote: Email your PCB files to Sales@pcbsync.com (Preferred for large files) or submit online. We will contact you promptly. Please ensure your email is correct.

Drag & Drop Files, Choose Files to Upload You can upload up to 3 files.

Notes:
For PCB fabrication, we require PCB design file in Gerber RS-274X format (most preferred), *.PCB/DDB (Protel, inform your program version) format or *.BRD (Eagle) format. For PCB assembly, we require PCB design file in above mentioned format, drilling file and BOM. Click to download BOM template To avoid file missing, please include all files into one folder and compress it into .zip or .rar format.