FERROELECTRIC MEMORY

PROBLEM TO BE SOLVED: To provide a ferroelectric memory in which data can surely be protected even if process parameters are changed, the time for reliability evaluation test can be shortened, and the destruction of a device due to the test can be prevented. SOLUTION: Power source voltage VDD is detected by using a power source voltage detecting circuit 4 having a stable detection level, when the detected voltage RREFA is a set detection level VREFA or less, an external input terminal XEXTCE is deactivated by using an output signal of a differential amplifier circuit 3 and data is protected. Thereby, stable data protection can be performed.