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| | VCC and Ground Plane Thermal Relief - OrCAD Community (Site not responding. Last check: 2007-11-06) |
 | | The purpose of thermal reliefs is to give some degree of heat insulation between the hole and the planes of the board, assuming that the hole is to contain the lead of a component which is to be soldered. |
 | | On a normal routing layer (not a plane layer), any hole will have a copper pad which is somewhat larger than the drill size, maybe about 14 mils or so in diameter for inner routing layers, and maybe more for outer routing layers. |
 | | Thus, on a plane layer, the structure we would see at our example hole would be only a colored ring, the antipad, 54 mils inner diameter and 84 mils outer diameter. |
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