1. What is Via Annular Ring?

The via annular ring refers to the copper ring that surrounds a drilled hole in a printed circuit board (PCB). It ensures proper electrical connection between different layers of the PCB and provides mechanical support for the via.

2. How Does the Calculator Work?

The calculator uses the annular ring formula:

Where:

• \( D_{\text{pad}} \) — Pad diameter (units)
• \( D_{\text{hole}} \) — Hole diameter (units)

Explanation: The annular ring is calculated as half the difference between the pad diameter and the hole diameter, representing the width of the copper ring around the via.

3. Importance of Annular Ring Calculation

Details: Proper annular ring calculation is crucial for PCB manufacturing as it ensures reliable electrical connections, prevents drill breakout, and maintains the structural integrity of the vias. Insufficient annular ring can lead to manufacturing defects and circuit failures.

4. Using the Calculator

Tips: Enter both pad diameter and hole diameter in the same units. Ensure the pad diameter is larger than the hole diameter. Typical units include millimeters (mm) or mils (thousandths of an inch).

5. Frequently Asked Questions (FAQ)

Q1: What is the minimum recommended annular ring size?
A: The minimum annular ring size depends on the PCB manufacturer's capabilities, but typically ranges from 0.05mm to 0.1mm for standard designs.

Q2: Why is annular ring important for PCB reliability?
A: Adequate annular ring ensures proper plating of the via hole, prevents drill breakout, and maintains electrical connectivity between layers.

Q3: Can annular ring be different for different via types?
A: Yes, annular ring requirements may vary for through-hole vias, blind vias, and buried vias based on the PCB design specifications.

Q4: What happens if the annular ring is too small?
A: Too small annular ring can cause manufacturing defects, poor plating, and potential circuit failures due to broken connections.

Q5: How does annular ring affect PCB cost?
A: Smaller annular rings may require more precise manufacturing processes, potentially increasing production costs. Standard annular ring sizes are generally more cost-effective.