A memory device is provided. The memory device includes a cell array having memory cells; n word lines sequentially arranged and including a first word line, an n-th word line, and word lines interposed between the first word line and the n-th word line; bit lines; a first power node located adjacent to the first word line; a second power node located adjacent to the n-th word line; a first switch connected between the first power node and the cell array; a write driver located adjacent to the n-th word line and connected to the bit lines; and a switch controller configured to control the first switch to isolate the first power node from the memory cells during a write operation on memory cells connected to the first word line.