Read-decoupled radiation hardened RD-DICE SRAM cell for low-power space applications

Conventional 6T Static Random Access Memory(SRAM) cell suffers from data flip (Single event upset) due to continuous bombardment of radiation particles in the space environment. To mitigate single-event upset (SEU) which arises due to radiation, radiation-hardened SRAM cell such as dual interlocked storage cell (DICE) is proposed in the literature. However, DICE SRAM uses 4 bit-lines for the read and write operations, and which consume significantly high power when compared with the conventional 6T SRAM cell with 2 bit-lines. To resolve this issue, we propose a read-decoupled DICE SRAM cell, which uses only single bit-line for a read operation. Simulations results obtained from Spice for 1 KB SRAM array implemented in UMC 65nm and SCL 180nm technology node show that by simply decoupling read and write operation in DICE SRAM, read energy(write energy) and read delay(write delay) reduce by at least 72 %(17%) and 67%(37%) respectively. SEU results obtained from Cogenda tool show that the read-decoupled DICE is immune to radiations as is DICE.