Management of electronic part obsolescence for EMC

The obsolescence of electronic components is a recurring problem for manufacturers of electronic equipment, who may integrate hundreds of different component references. This obsolescence may be due to rapid technological developments in the sector, changes in regulations, shortages of raw materials, saturation of production resources or exceptional events. If this problem is not anticipated, the risk is a supply disruption leading to a halt in equipment manufacturing. In this context, equipment manufacturers are implementing strategies and tools to manage component obsolescence, such as identifying several equivalent components developed by different manufacturers (multisourcing).

Beyond the risk of supply disruption, obsolescence and multisourcing can have other consequences. In safety-critical fields of application (automotive, aeronautics, transport, energy, weapons), guaranteeing the electromagnetic compatibility (EMC) of electronic equipment is an essential and unavoidable constraint. This must be guaranteed regardless of the modifications made to the initial version of the equipment, such as the replacement of an obsolete component or the use of another source. The EMC qualification of a piece of equipment, as well as the demonstration that the change of component will not compromise EMC, currently requires standardized EMC tests, which are time-consuming and very costly for equipment manufacturers. This situation has led equipment manufacturers to look for better ways of managing the obsolescence of components with regard to EMC, i.e. ways of justifying not carrying out EMC tests, or only partially carrying them out.

Although replacement components are equivalent to the initial ones (pin-to-pin compatibility, identical functional specifications), their emission and electromagnetic immunity levels can vary widely. EMC expertise, backed up by component-level measurement techniques and electrical and electromagnetic simulation, is therefore essential to assess the risk of EMC regression following the replacement of a component, without repeating the normative EMC tests.

This article first describes the challenges posed by component obsolescence and multisourcing on the EMC qualification of electronic equipment, and justifies the need for component obsolescence methods to optimize EMC qualification. In the second part, the article illustrates the difficulty of anticipating the impact of component change on the EMC of equipment, through several examples of emission and immunity comparisons of equivalent components. In the third part, the article presents the various existing and published approaches to optimizing the EMC (re)qualification of electronic equipment.