A method for designing a read-only memory (ROM), and related device, includes partitioning a dataset into two or more sub-datasets that each have the same address space, but are of a smaller bit-width than the original dataset. The sub-datasets are row collapsed, and then respective memory cells for the sub-datasets are provided. The output of the memory cells provides the output of the ROM. Each memory cell includes a decoder that maps addresses to word lines based on mapping information obtained during row collapsing, and a logic array driven by the decoder that encodes the data words of the sub-dataset.