| 摘要 |
Since a ferroelectric memory device cannot employ a VCC/2 precharge scheme widely used in DRAM, its array noise and power consumption are large. Further, a ferroelectric capacitor is deteriorated in its characteristics due to its fatigue and imprint. To avoid this, data line pairs are precharged to two voltages VCC and VSS. As a result, a voltage on a data line in a memory cell array MCA varies symmetrically with respect to VCC/2 as its center to thereby reduce the array noise. Further, when early sense and early precharge operations are carried out based on charge sharing between data lines of different precharge voltages, the power consumption can be reduced. Furthermore, when the precharge voltages are switched for respective data lines, reverse and non-reverse polarization are alternately carried out in the ferroelectric capacitor in the memory cell to suppress its fatigue and imprint.
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