A scan chain partition includes a serial input coupled to a scan input signal pin of a module under test. A plurality of scan sub-chains is coupled to the serial input. A scan sub-chain output multiplexer is coupled to the plurality of scan sub-chains for sequentially selecting only one of the scan sub-chains in response to a scan sub-chain control signal. A scan sub-chain controller generates the scan sub-chain control signal and gates a scan clock signal to only a scan clock input of the selected scan sub-chain.