| 摘要 |
<p>PURPOSE:To enable information with multilevels to be stored by performing the storage of the information based on difference in the Zener breakdown voltage of a Zener diode. CONSTITUTION:A word line WL is activated by a decoder 21 based on word address signals (A1-An), and only one sense amplifier 22 is activated by setting a chip enable signal CE at 'H', and a write bit line selection signal W1 at 'H' selectively, and only a bit line BL connected to the sense amplifier is set at an energized state, then, the Zener diode TD whose cathode and anode are connected to selected word line WL and bit line BL, respectively, is selected. By setting the potential of the selected bit line BL at the ground level, and supplying a pulse of high voltage on the selected word line WL by the decoder 21 for a prescribed time, the information can be written by changing the Zener voltage by multiple stages. In such a way, it is possible to perform the storage of the information with multilevels.</p> |
