Semiconductor memory device with mos transistors, each including a floating gate and a control gate, a control method thereof, and a memory card including the same

Abstract

A semiconductor memory device includes memory cells, write bit lines, read bit lines, latch circuits, a n-channel MOS transistor, and voltage setting circuits. The memory cell includes a first MOS transistor having a charge accumulation layer and a control gate. The first MOS transistors are connected commonly to the write bit lines and read bit lines. The latch circuits are provided for the write bit lines and hold write data for the memory cells. The n-channel MOS transistor transfer '1' data to the latch circuits in a data latch operation. The voltage setting circuits supply a potential corresponding to '0' data to the write bit lines in a read operation. In a data latch operation, the latch circuit corresponding to the write bit line connected to the memory cell into which “0” data is to be written latches the potential supplied to the write bit lines in a read operation.