An integrated circuit designed to carry out one or more specific functions and implemented on a single semiconductor chip in order to reduce the size of a system, reduce the number of interconnections that are required at printed circuit board level, and to reduce the number of components that, at a lower level of integration, might otherwise be used to implement the function. ASICs are economic where production runs in the high hundreds are required and have become viable due to advances in VLSI design, layout, and fabrication technology. See also semicustom.