A circuit of reducing a pop-up noise in a digital amplifier includes a switch unit and a switch signal generator. The switch unit is coupled in parallel to an output load between an output node of the digital amplifier and a reference node. The switch unit controls a current flowing through the output load by forming a conduction path between the output node and the reference node in response to a switch signal. The switch signal generator generates the switch signal in response to a switch control signal indicating a power-on or a power-off. The pop-up noise is reduced by the conduction path that is formed when the digital amplifier is powered on or off.