Abstract: A sense amplifier of a semiconductor memory device includes: a precharge section for precharging the dummy line and bit line with a required voltage by means of an equalizer signal transferred from an external; a data sensing section for receiving and latching voltage of the bit line and voltage of the dummy lines as first and second input signals, respectively, by means of a sense amplifier enable signal transferred from the external, thereby sensing data from the memory cell and generating it as an output signal; a precharge enable section for disabling the precharge section by means of the sense amplifier enable signal transferred from the external when in a data sensing operation or for enabling the precharge section when not in a data sensing operation; and a data sensing enable section for transmitting the voltage of the bit line and the voltage of dummy line as first and second input signals, respectively, to the data sensing section according to the sense amplifier enable signal from the external depe