| 摘要 |
PURPOSE:To read out information stably even in the event of variation of supply voltage, by prescribed the precharge setting voltage of a bit line of a semiconductor memory device whose memory element is an MOS capacitor, and the opposed electrode side of the capacitor. CONSTITUTION:By an electric power source PS2 provided with the same voltage dividing resistances R2, R2 between supply voltage Vcc and ground voltage Vss, on the opposed electrode side of the opposite side of, a transistor Q5 for a transfer gate of an MOS capacitor CS of a memory cell MC, a pair of bit lines BL and anti- BL are precharged to Vc=(Vcc-Vss)/2. Immediately after the voltage Vcc has been varied, the voltage Vc is not varied by a time constant, and voltage of a joint point N1 is not varied. Also, even in case the precharge voltage Vc has been varied with the voltage Vcc as time elapses, the line BL and the opposed electrode side of the capacitor Cs are charged to the same voltage Vc, charge of the capacitor Cs is not varied, and immediately after supply voltage has been varied, and even after the variation, information is still read out stably, and a semiconductor memory device which is operated stably at a high speed is obtained. |
