A semiconductor device includes an intellectual property (IP) block, a clock management unit, a critical path monitor (CPM), and a CPM clock manager included in the clock management unit. The clock management unit is configured to receive a clock request signal, indicating whether the IP block requires a clock signal, from the IP block and perform clock gating for the IP block based on the received clock request signal. The CPM is configured to monitor the clock signal provided to the IP block to adjust at least one of a frequency of the clock signal provided to the IP block and a voltage supplied to the IP block. The CPM clock manager is configured to perform the clock gating for the CPM.