A data line control circuit has a data line driving circuit and a write-assist data line driving circuit. The data line driving circuit is used to drive differential data lines during a write operation of at least one memory cell. The write-assist data line driving circuit is used to drive at least one write-assist data line during the write operation of the at least one memory cell, wherein the at least one write-assist data line is isolated from the differential data lines, and is driven to have a first voltage transition from a first voltage level to a second voltage level, such that one of the differential data lines has a second voltage transition from a third voltage level to a fourth voltage level that is induced by the first voltage transition via capacitive coupling.