SEMICONDUCTOR STORAGE DEVICE

摘要

PURPOSE:To obtain a sufficient data writing quantity so as to improve the accessing time and noise margin characteristics by strictly setting a data discriminating reference based on a data input latched at the time of writing when verification is made. CONSTITUTION:Complementary bit data are respectively written in two sets of memory cells MC and the inverse of MC through a bit lines pair BL and the inverse of BL respectively connected with the two sets of memory cell arrays through n-channel enhancement type transistors 5 and 5' for writing data. A differential amplifier type sense amplifier 1 discriminates the data after amplifying the potential difference between each line BL and the inverse of BL of the bit line pair and a latching means 13 tentatively latches the data inputted at the time of writing. Then the data discriminating reference at the time of verification immediately after writing is set more severely than the discriminating reference set at the time of normal data readout based on the data latched by the latching means 13. Therefore, a sufficient data writing quantity is obtained and the accessing time and noise margin characteristics are improved.