Flash memory device and method of erasing the same

A flash memory device, comprising:

• a plurality of sector units including a plurality of memory cells;
• a sense amplifier control unit for generating a plurality of sense amplifier enable signals;
• a plurality of sense amplifier units driven by the sense amplifier enable signals and having a plurality of sense amplifiers, wherein the sense amplifiers operate in an automatic verify program mode to automatically perform program and verify operations for corresponding cells, upon pre-program and post-program operations of the memory cells, and operate in an iterative program and verify mode to iteratively perform erase and verify operations for corresponding cells, upon the erase operation;
• and
• a plurality of connection switching units for transferring a bias voltage applied from the sense amplifier unit of the plurality of the sense amplifier units to the corresponding memory cells of the sector, depending on a plurality of control 'signals.