A dynamic random access memory device selects a row of memory cells from a plurality of memory cell sub-arrays with main word lines and sub-word lines for a data access, and data bits read out from the row of memory cells are amplified by a sense amplifier circuit array, wherein a row block address decoder and a column block address decoder supply a first enable signal and a second enable signal to a row of memory cell sub-arrays and a column of memory cell sub-arrays so that only one of the sense amplifier circuit arrays is powered for the amplification, thereby decreasing peak current consumed by the sense amplifier circuit arrays.