CONVERTING AEROFLEX UTMC UT9Q512 4M SRAM into an SEU IMMUNE 1M X 1 SRAM

This application note describes how to use two UT9Q512 4M SRAMs and one UT54ACS151 logic device to mimic a 1Mx1 SRAM. As shown below, the single bit is written into three locations of the same. When the data is read out, it is used in a voting system to select either a 0 or a 1 output. This voting method virtually makes it immune to SEU hits. Since the bits of a word are not physically adjacent on the die, it is nearly impossible for one particle to cause two bits to flip in the same word. As such, it would require multiple particle hits to cause an upset.