Heat that has been generated inside the chip escapes to the outside air over various paths: by means of conduction, convection, or emission/radiation. The source of heat generation is the IC chip itself. The heat is transmitted by conduction to the package, lead frame, die attach pads, and the printed circuit board. The largest path for heat conduction is from the chip through the package leads into the printed circuit board. The heat is then transmitted from the surfaces of the printed circuit board and the IC package to the ambient atmosphere by convection and emission/radiation.