FLASH MEMORY DEVICE FOR OVER-SAMPLING READ OPERATION AND READ METHOD THEREOF

摘要

A flash memory device for performing an over-sampling read operation and a data read method thereof are provided to offer a high speed and reliability memory system by implementing the memory system capable of performing the over-sampling read operation to memory cells at high speed. A multi-bit flash memory device(110) performs a normal read operation and an over-sampling read operation, and the normal read operation outputs first data by detecting selected memory cells with first read voltages set among threshold voltage distributions. The over-sampling read operation outputs second data by detecting the selected memory cells with second read voltages included in a range of the threshold voltage distributions. A memory controller(120) enables the multi-bit flash memory device to perform the over-sampling read operation selectively during a read operation by responding to an external request. The memory controller determines read data according to a soft decision algorithm by referring to the first and second data when the over-sampling read operation is selected.