Some Of The Most Common Failure Modes of Electronics

Electronic component failure occurs  most commonly at the beginning and near the end of the lifetime of the parts. The failure of components is typically packaging related. Sometimes the failure is slow which gives time to identify the component and replace it before it fails completely destroying the equipment.

While the failures may be rapid or violent and unexpected, these are tested for during product certification. Some of the most common reasons for components to fail include:

•    Over-current and over-voltage

•    Over temperature

•    Radiation

•    Contamination

•    Packaging

•    Connected incorrectly

•    Manufacturing defect

While you buy electronic component you need to understand that everything fails at some point and electronics are no exception.

The following major failure modes can help designers create more strong designs and even plan for expected failures.

Component Package Failures

The components are properly packed to provide two main function, to protect the component from environment and to provide a way for the component to be connected to the circuit. It may happen that the packing layer may break, thus the outside factors such as humidity and oxygen can affect the ageing of the component and cause it to fail much faster. The component can also be subject to mechanical failure of the package caused by thermal stress, chemical cleaners, and ultraviolet light.

Solder Joint and Contact Failures

The main means of contact between a component and circuit is the solder joint. If you use a wrong type of solder with the component or PCB it can lead to electro migration of the elements in the solder that form fragile layers called inter-metallic layers. These layers lead to broken solder joints.

Another reason for solder joint failure is thermal cycles, especially if the thermal expansion rates of the materials are different. As all of these materials heat up and cool down, massive mechanical stress can damage the component, or the PCB trace may be divided into layers. Tin whiskers on lead free solders can also be a problem.

PCB Failures

Printed circuit boards are susceptible to environmental influences. The soldering and operational environment of a PCB often leads to a variety of PCB failures. Residues of solder flux may aid corrosion, and other materials on PCBs can cause electrical leaks. Other causes of failure include stemming from the manufacturing process. During manufacturing the layers in a PCB board may be uneven leading to short circuits, open circuits, and crossed signal lines. The chemicals used in PCB board drawing may not be fully removed and traces may be formed. The solder flux used to attach all of the components to a PCB may remain on the surface of a PCB which will corrode any metal that comes in contact with it. Thermal cycling is another cause of PCB failures which can lead to de-lamination of the PCB.

All these causes can be prevented by adjusting the design of the circuit accordingly. These failures like mechanical failure, packaging failures etc can be avoided by taking proper care.