US Patent 7190339 Ferroelectric memory device and display drive IC

A ferroelectric memory device capable of structurally reducing data deterioration. In this ferroelectric memory device, bitlines are hierarchized, and sub-bitlines subordinate to the bitlines through sub-bitline select switches are provided in each of a plurality of block regions. The block regions are sequentially selected along an increment direction, and wordlines in each block are sequentially selected along the increment direction from the lowest wordline to the highest wordline. The number “n” of wordlines arranged in each block region is set equal to or less than a predetermined limit number about relaxation.