Patent ID: 8441844

Claim:
A method of writing in a memory device comprising a plurality of magnetoresistive random access memory (MRAM) cells arranged in rows and columns, each MRAM cell to be written by using a thermally-assisted switching (TAS) write operation, including a magnetic tunnel junction having a resistance that can be varied during a write operation when the magnetic tunnel junction is heated at a high threshold temperature, and a select transistor electrically coupled to the magnetic tunnel junction; a plurality of word lines connecting MRAM cells along a row; and a plurality of bit lines connecting MRAM cells along a column; comprising, during the write operation: supplying a bit line voltage to one of the bit lines and a word line voltage to one of the word lines for passing a heating current through the magnetic tunnel junction of a selected MRAM cell; once the magnetic tunnel junction has reached the high threshold temperature, varying the resistance of the magnetic tunnel junction; and cooling the magnetic tunnel junction such as to freeze said resistance in its written value; said word line voltage is a word line overdrive voltage being higher than the core operating voltage of the MRAM cells such that the heating current has a magnitude that is high enough for heating the magnetic tunnel junction at the predetermined high threshold temperature.