In a ferro-electric memory including reference cells, if one reference cell is associated with a plurality of normal cells, a period in which “L” data is written in the reference cell and a period in which “H” data is written or read out in/from the reference cell are controlled to be shorter...http://www.google.fr/patents/US7092275?utm_source=gb-gplus-shareBrevet US7092275 - Memory device of ferro-electric
