RELIABILITY MEASUREMENT OF MEMORY SYSTEM USING SPARE BLOCKS

Reliability requirements depend on the application. Missile and space borne application require high levels of reliability whereas ground based applications require lower levels of reliability. The reliability of these systems can be achieved by using redundancy and repair. Reconfiguration (repair) of memory arrays with the help of spare memory lines is the most used technique for reliability improvement of memories with faults. Faulty cell in memory arrays are closely spaced.. This is called as fault clustering. This paper initially examines a quadrat-based fault Model for memory elements under clustered faults to define a foundation of measurement. Then reliability calculations are done long-life dependability of a fault-tolerant memory system with hierarchical active redundancy, which consists of spare columns in each memory module.