Purpose

If the drill that is located inside the thermal has no sufficient electrical connectivity to the surrounding plane, it may not provide the required functionality, especially in high-speed designs.

Function

Reports all incidents of reduction in thermal connectivity.

Measurements are circles whose diameter in mils represents the percentage reduction in connectivity. The larger the circle the more serious the reduction.

Activation

When layer is negative and thermal pads in the layer are flashed (not drawn).

Known Limitations

The size of the circle representing the connectivity reduction is always given in mils. The results of this category are best reviewed in imperial units.

The overall electrical connectivity of a thermal pad is defined to be the sum of the defined spoke widths. The actual connectivity is the sum of actual remaining spoke widths. The percentage reduction is defined as follows:

Defined connectivity minus actual connectivity
divided by actual connectivity