US Patent 7630239 Semiconductor device

The present invention provides a semiconductor device which comprises a plurality of memory cells which stores data therein based on threshold voltages thereof, a plurality of bit lines on which read signals based on the stored data of the memory cells appear respectively, a plurality of sense amplifiers which are respectively disposed corresponding to the bit lines and which respectively detect the read signals having appeared on the bit lines and output first and second signals respectively having logical levels different from one another from first and second nodes, based on the detected read signals, and a determination unit which determines, based on the first and second signals received from the first and second nodes of the sense amplifiers, whether the threshold voltages of the memory cells are normal.