NONVOLATILE SEMICONDUCTOR STORAGE DEVICE AND SEMICONDUCTOR DEVICE

摘要

PURPOSE: To correctly discriminate the nondefection/defection of a memory by the presence or absence of volatilization of memory cells by providing a changing part of the sense characteristic of a sense-amplifier and a volatilization discriminating part of memory cells and an output part of the discrimination result and performing a pseudo readout. CONSTITUTION: A sense characteristic changing circuit 9 of changing part of sense characteristic changes the reference of the sense characteristic of a sense- amplifier consisting of a differential amplifier 6, etc., to a rigorous state or a relaxed state. The EXOR circuit 12 of a volatilization discriminating part compares levels of data read out by the sense-amplifier of before and after the changing of the sense characteristic and discriminates the presence or absence of volatilization of memory cells with the compared result and a volatilization detection terminal 13 outputs the compared result. Thus, the erroneous readout of data of memory cells are previously and correctly prevented.