SEMICONDUCTOR MEMORY DEVICE

摘要

PURPOSE:To confirm easily the operating state of a spare memory by writing the same information to all memory elements when a spare address decoder is inactivated and reading it successively. CONSTITUTION:When external input terminal 56 of a spare row address decoder is brought into a high level, a transistor (TR) 55 is turned on, a node (b) is brought into a low level and a TR38 is kept off. Then, a word line 42 is brought into a low level and the spare row address decoder is inactivated. Similarly, a spare column address decoder is inactivated, the same prescribed information is written in all memory elements and read sequentially, then the operating state of the spare memory whether or not the spare memory is used or the address corresponding to the memory when in operation is confirmed easily.