A built-in Hamming code ECC circuit for DRAMs

An error checking and correcting (ECC) technique that checks multiple cell data simultaneously and allows fast column access is described. The ECC circuit is optimized with respect to the increase in the chip area and the access-time penalty, and can be applied to a 16-Mbit DRAM with 20% chip area increase and less access-time penalty. The soft error rate has been estimated to be about 100 times smaller than that of the basic horizontal-vertical parity-code ECC technique. >