US Patent 7088631 Semiconductor storage apparatus

A semiconductor storage apparatus includes a cell array including memory cells and reference cells, normal column selection transistors connected to columns of the memory cells, a normal data line array including normal data lines connected to columns of the memory cells, first dummy data lines formed of a same wiring layer of which the normal data lines are formed, a normal data line charging circuit, reference column selection transistors connected to reference columns of the reference cells, a reference data line array including reference data lines formed of a same wiring layer of which the normal data lines are formed, second dummy data lines formed of a same wiring layer of which the reference data lines are formed, a reference data line charging circuit, a first dummy data line charging circuit, a second dummy data line charging circuit, and a sense amplifier which senses data stored in the memory cells.