A New Approach to the Attainment of the Highest Possible Reliability in Tantalum Capacitors

The question of how to achieve the highest possible reliability for Tantalum capacitors is discussed from both the theoretical and practical point of view. A method of achieving reliabilities of the order 95 per cent at a confident level of 95 per cent or better is described which involves an analytical treatment of the physics of the main mode of failure, all accounting for over 90 per cent of a failure; and a statistical model is derived which demonstrates this reliability on a highly accelerated test. The test is applicable on a 100 per cent basis to the test capacitors and, as it is nondestructive, it allows the attainment of a reliability figure for each individual unit. This also provides a method of attaining very high reliabilities at a low cost and the test can be carried out in 24 hours or less.