1. What is Via Annular Ring?

The annular ring in PCB design refers to the copper area that surrounds a drilled via hole. It provides the electrical connection between the via and the copper trace on the PCB layer.

2. How Does the Calculator Work?

The calculator uses the annular ring formula:

Where:

• \( Via\ Diameter \) — Outer diameter of the via pad (mm)
• \( Pad\ Diameter \) — Diameter of the drilled hole (mm)
• \( Ring\ Width \) — Width of the copper ring around the hole (mm)

Explanation: The annular ring is calculated as half the difference between the via pad diameter and the drilled hole diameter.

3. Importance of Ring Width Calculation

Details: Adequate annular ring width is crucial for reliable PCB manufacturing. Insufficient ring width can lead to connection failures during drilling or poor electrical connectivity.

4. Using the Calculator

Tips: Enter via diameter and pad diameter in millimeters. Both values must be positive numbers, and via diameter must be larger than pad diameter for a valid calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the minimum recommended annular ring width?
A: Typical minimum annular ring width is 0.15mm for standard PCBs, but this can vary based on manufacturer capabilities and IPC standards.

Q2: Why is annular ring important in PCB design?
A: It ensures proper electrical connection, provides mechanical strength, and accommodates drilling tolerances during manufacturing.

Q3: What happens if annular ring is too small?
A: Small annular rings can cause breakout (drill hitting the edge), poor connections, and reduced reliability in the final product.

Q4: Are there different requirements for different PCB layers?
A: Yes, inner layers typically require larger annular rings due to registration tolerances during lamination processes.

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