Theme: SPECCTRA / ELECTRA Auto router interface
Why get the vias wider than entered to the dialog?
The basis for a plated through-hole (via) is always the selected drill hole. TARGET uses the largest value of the following 3 calculations:
o "Drill hole diameter minimum" from the Autorouter dialog box
o Track width of the signal x 0.7
o Track width of the signal - 2 x "Width of the rest ring (annular ring)".
2 x "Width of the minimum rest ring" is always added to the drill hole. This results in the diameter of the via. Wider signals also have wider vias.
