A memory device includes a memory cell array that a plurality of memory cells, an edge buffer circuit that is placed in a first region adjacent to one side of the memory cell array and receives an external signal from the outside through a pad, and a middle buffer circuit that is placed in a second region adjacent to an opposite side of the memory cell array and receives a differential small-swing signal corresponding to the external signal from the edge buffer circuit through first and second signal lines above the memory cell array. The edge buffer circuit drives the first and second signal lines based on the external signal such that the differential small-swing signal is transmitted to the middle buffer circuit.