1. What is a PCB Via Size Calculator?

Definition: This calculator determines the appropriate via hole diameter based on the lead diameter of the component.

Purpose: It helps PCB designers and engineers create properly sized vias for component leads and current requirements.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• Hole Diameter — Recommended via hole size (mm)
• Lead Diameter — Diameter of the component lead (mm)
• 0.25mm — Standard clearance allowance

Explanation: The formula ensures proper clearance for component leads while maintaining structural integrity of the via.

3. Importance of Proper Via Sizing

Details: Correct via sizing ensures reliable solder joints, proper current carrying capacity, and manufacturability of the PCB.

4. Using the Calculator

Tips: Enter the lead diameter in millimeters. The calculator will recommend a hole diameter with standard clearance.

5. Frequently Asked Questions (FAQ)

Q1: Why add 0.25mm to the lead diameter?
A: This standard clearance ensures the lead fits comfortably while allowing space for solder flow during assembly.

Q2: When should I use a different clearance?
A: For high-current applications or wave soldering, you might need larger clearances (up to 0.4mm).

Q3: How does this relate to via plating?
A: The calculated diameter is the finished hole size after plating (typically subtract 0.1mm for plating thickness).

Q4: What about via current capacity?
A: For current requirements, you may need larger vias. A general rule is 1A per 0.3mm of via diameter.

Q5: How does this apply to SMD vias?
A: For SMD vias, consider both the pad size and the current requirements when determining via size.