| 摘要 |
PROBLEM TO BE SOLVED: To provide a nonvolatile semiconductor memory device which is programmable at a high-speed transfer rate. SOLUTION: In a read operation, for example, 32 pieces of data are read en bloc with 32 sense amplifiers. Thereafter, read data is outputted by 4 bits at a time. A memory cell array operates at a low frequency being one-eighth of an actual data output frequency. On the other hand, in a write-in operation, data is transferred by 1 bit per one cycle at a time to the semiconductor memory device from the outside. For this reason, a write-in operation is made possible even with a high frequency by providing many pipeline latches in a write access path. In short, at the time of read-out, the memory array operates at the low frequency being one-eighth of the data output frequency and at the time of write-in, it performs an operation such as to writing data for every clock. Thus, this memory is effective in memory cells which can perform the writing of data at high speed like especially an MRAM (Magnetic Random Access Memory). COPYRIGHT: (C)2004,JPO&NCIPI
|
