Memory system capable of switching between a reference voltage for normal operation and a reference voltage for burn-in test

摘要

A memory system that generates a reference voltage unaffected by supply voltage variations and is suitable for performing burn-in test is attainable by employing the following configuration. For example, in an MRAM containing a TMR element (Rij) and an N channel MOS transistor (Mij), as memory element, there is disposed a switching circuit (SW1) capable of switching between the state of applying a reference voltage (VrefN) to a memory element and the state of applying a reference voltage (VrefB) for burn-in test having a larger value than the reference voltage (VrefN) to the memory element. At the time of burn-in test, instead of the reference voltage (VrefN) for normal read operation, the reference voltage (VrefB) for burn-in test can be applied via a sense circuit (SC) to the memory element, by applying mode change signals (MODE1 to MODEn) from the exterior and operating the switching circuit (SW1) via a decode circuit (TD).