Transient fault characterization in dynamic noisy environments

Technology trends are increasing the frequency of serious transient (soft) faults in digital systems. For example, ICs are becoming more susceptible to cosmic radiation, and are being embedded in applications with dynamic noisy environments. We propose a generic framework for representing such faults and characterizing them on-line. We formally define the impact of a transient fault in terms of three basic parameters: frequency, observability and severity. We distinguish fault modes in systems whose noise environment changes dynamically. Based on these ideas, the problem of designing on-line architectures for transient fault characterization is formulated and analyzed for several optimization goals. Finally, experiments are described that determine transient fault impact and the corresponding tests for various simulated fault modes of the ISCAS-89 benchmark circuits