US Patent 7571276 Read operation for semiconductor memory devices

Disclosed is a method of performing a read operation in a NAND/RAM semiconductor memory device. The semiconductor memory device comprises a NAND flash memory device having a memory cell array and a page buffer, and a data RAM outputting data in response to a clock signal received from a host. The method comprising; sensing data stored in one page of the memory cell array in the page buffer, transferring the sensed data from the page buffer to the data RAM in multiple blocks via a corresponding number of transfer operations, and reading the transferred data from the data RAM in response to the host clock signal, wherein a read-out operation for the transferred data commences during any one of the plurality of transfer time periods.