The AT68166HT MCM incorporates four 4Mbit AT60142HT 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.