The AT68166F/G MCM incorporates four 4Mbit AT60142FT SRAM dice. It can be organized as either one bank of 512Kx8, two banks of 512Kx16 or four banks of 512Kx8. It combines rad-hard capabilities, a latch-up threshold of 80MeV.cm/mg, a Multiple Bit Upset immunity and a total dose tolerance of 300Krads, with a fast access time.