Semiconductor integrated circuit device

Abstract

A semiconductor integrated circuit device is configured using a DRAM and an SRAM between which data transfer is performed by way of a data transfer circuit using data transfer bus lines. Herein, the DRAM is divided into at least two DRAM arrays, each of which contains a number of columns each consisting of memory cells. In addition, the columns are arranged in mixture in connection with external I/O terminals respectively in such a way that columns respectively containing memory cells which are simultaneously subjected to read operations within a same cycle are arranged not to adjoin each other. Thus, it is possible to reduce a probability in which multiple memory cells which are simultaneously subjected to read operations within the same cycle exist within a range of an area under influence of charged particles, which are produced locally due to neutrons. Even if data of memory cells which are concentrated at a certain region are simultaneously placed under influence of the charged particles, it is possible to remarkably reduce a number of chances in that multiple bits of data being read out to the external I/O terminals go defective simultaneously.