| 摘要 |
PROBLEM TO BE SOLVED: To more hasten the discharge start timing of unwanted charges to speed up the access time in a semiconductor memory which reads data with a voltage applied to bit lines while unwanted charges accumulated on the bit lines, etc., are discharged. SOLUTION: In an NAND type memory, a discharging transistor TD1 is connected to a bit line Ca, and a discharging transistor TD2 and a charging transistor TC1 are connected to the sources of memory transistors TM1, TM2,.... In reading data, the discharging transistors TD1, TD2 are once set on to discharge unwanted charges and then the charging transistor TC1 is set on to go into the data reading operation wherein a drive circuit 20 for driving these transistors is operated synchronously with system clocks CLK1, CLK2 of a CPU for reading data from a memory. As the result, just after the read timing at which the CPU reads data from the memory, the discharging operation of the unwanted charge can be started to thereby hasten the access time.
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