Semiconductor memory device

Abstract

A semiconductor memory device having a plurality of memory arrays in which static memory cells are disposed in a lattice arrangement at intersections of word lines and complementary data lines. The load circuits thereof are characterized as having a varying impedance effected by the combination of a first pair of P-channel MOSFETs disposed between the complementary data lines and a first node supplied with a first supply voltage and kept normally in an ON-state, and a pair of transistors, such as a second pair of P-channel MOSFETs, similarly connected as the first pair of P-channel MOSFETs and which are turned off selectively in accordance with a control signal corresponding to a predetermined selection timing signal in a write-in mode. The semiconductor memory device has a plurality of switching circuits which are coupled between the plurality of complementary data lines and a pair of data read and write lines. Each such switching circuit has a first pair of N-channel MOSFETs for selectively coupling the data input circuit of the memory device to a corresponding pair of complementary data lines via the pair of write data lines during a data write-in mode and a pair of P-channel MOSFETs for selectively coupling the corresponding pair of complementary data lines to the data output circuit via the pair of read data lines during the data read-out mode thereof.