An integrated circuit includes a plurality of power rail pairs and a circuit chain. Each of the plurality of power rail pairs includes one of a plurality of high power rails configured to provide a first power supply voltage and one of a plurality of low power rails configured to provide a second power supply voltage that is lower than the first power supply voltage. The circuit chain includes a plurality of unit circuits that are cascade-connected such that an output of a previous unit circuit is provided as an input of a next unit circuit. The plurality of unit circuits are connected distributively to the plurality of power rail pairs.