| 摘要 |
PURPOSE:To perform both fast and slow access and to provide low power consumption in the slow access by sending out the signal of a bit line via a sense amplifier in a high speed mode, and setting the sense amplifier in a non- driving state in a slow speed mode. CONSTITUTION:When the high speed mode is set and also, a readout command is issued, the sense amplifier 20 comprised of PMOS transistors 23, 24 and MHOS transistors 25, 26, and 27 is driven, and the signals of the bit lines 201, 202 are sent out to a data bus 206 via the sense amplifier 20. When the slow speed mode is set and also, the readout command is issued, the sense amplifier 20 is set in the non-driving state, and the signals of the bit lines 201, 202 are sent out to the data bus 206 without passing the sense amplifier 20. Therefore, since the sense amplifier 20 is set in the non-driving state in a readout operation in the slow speed mode, power consumption can be reduced, which realizes power saving by that share. |
