A flip-flop includes a conditional boosting stage, a pulse generator and a latch. The conditional boosting stage includes a boosting capacitor, and is configured to pre-charge the boosting capacitor in accordance with a previous output signal and boost a node connected to the boosting capacitor upon a level the previous output signal being different from a level of a current input signal. The pulse generator is configured to generate a pulsed signal in accordance with transitions of a clock signal. The latch configured is to latch the current input signal to a current output signal in accordance with the pulsed signal.