SINGLE EVENT MIRRORING AND DRAM SENSE AMPLIFIER DESIGNS FOR IMPROVED SINGLE-EVENT-UPSET PERFORMANCE

This paper proposes and investigates schemes for hardening the convent ional CMOS cross-coupled DRAM sense amplifier to single event upset (S EU). These schemes, adapted from existing SRAM hardening techniques, a te intended to harden the dynamic random access memory to bitline-mode errors during the sensing period. Simulation results indicate that a 9k Omega L-resistor hardening scheme provides greater than 24-fold imp rovement in critical charge over a significant part of the sensing per iod. Also proposed is a novel single event (SE) mirroring concept for SEU hardening of DRAMs. This concept has been implemented for hardenin g the bitlines to hits on diffusion regions connected to the lines dur ing the highly susceptible high-impedance state of the bitlines, It is shown to result in over 26-fold improvement in the level of critical charge using a 2pF dynamic capacitive coupling.