| 摘要 |
PROBLEM TO BE SOLVED: To realize ferroelectric memories such as shadow RAM and so forth capable of raising S/N in respective modes simultaneously and also setting its capacitive coupling ratios easily. SOLUTION: At the time of a recall mode, high levels are supplied to electrodes of other sides of capacitors Csa, that is, to plate lines PL0a∼PLma and low levels are supplied to electrodes of other sides of capacitors Csb, that is, to plate lines PL0b∼PLmb and at the time of a read or write mode by a volatile mode, low levels of the same potentials are supplied to these plate lines. Thus, coupling ratios at the time of a recall operation are made large by making capacitors Csb act as load capacitances and at the time of the volatile mode, capacitive coupling ratios at the time of a normal readout operation are made small by making capacitors Csb act as information storage capacitances. |
