Association for Computing Machinery
A fundamental difference between ASICs (Application-Specific Integrated Circuits) and FPGAs (Field Programmable Gate Arrays) is that wires in ASICs are designed such that they match the requirements of a particular design. Wire parameters such as length, width, layout and the number of wires can be varied to implement a desired circuit. Conversely, in an FPGA, area is fixed and routing resources exist whether or not they are used, so the goal becomes implementing a circuit within the limits of available resources. The architecture for existing routing structures in FPGAs has evolved over time to suit the requirements of large, localized digital circuits.