MEMORY DEVICE HAVING PROGRAM TYPE SELF-REFRESHING FUNCTION AND TESTING METHOD THEREFOR

摘要

PURPOSE: To obtain a self-timing adjustment type refresh circuit capable of definitely testing refresh speed and a waiting-state interval in a non-penetrating manner. CONSTITUTION: A self-timing adjustment type refresh circuit 12 contains a self-timing adjustment type oscillator outputting a clock signal and program type pattern generators 56, 57 outputting a first signal pattern and a second signal pattern. A counter circuit 54 also receiving the clock signal is supplied with the first signal pattern, and a signal pulse is output when a driven count reaches a digital-pattern corresponding to the first signal pattern generated by the program type pattern generator 56. A refresh control logical circuit 52 receiving a pulse signal and corresponding to the refreshing of a part of the memory-array of semiconductor memory elements by refreshing a part of the memory-array is connected. The second signal pattern is used for setting the waiting-state interval of self-refresh operation.