How to Define the Pad Diameter?
Since EAGLE version 4.0 the default libraries contain only information about the drill diameter and the shape of a pad. The diameter value is set to auto, which is the same as 0, by default. What does this mean? The actual diameter will be calculated in the Layout Editor only. The calculation rule can be found in the Design Rules (menu Edit/Design Rules…) in the Restring tab. There you are allowed to define different calculation rules for Top, Bottom, and inner layers. How is it Calculated? The percentage, which is related to the drill diameter is used to calculate the width of the copper ring that is around the drilling. Default is 25%. A drill diameter of, for example, 0.032 inches results in a ring width of 0.008 inches. In the next step EAGLE checks if this value is within the given minimum and maximum boundaries. If so, the diameter of the pad results for our example in (2 * 0.008) + 0.032 = 0.048 inches. Let’s assume the minimum value is set to 0.010 inches. In this case the pr
