PCB Component Failure: How to Workaround a Tragedy

August 2, 2018 Altium Designer

 IoT wearable next to plant environment

 

Probably, the single thing that drew me to pursue a technical career was the existence of laws that stipulated if you follow the same procedure then you will get the same results. I have always taken comfort in having that security for my work. However, there is another law that at times supersedes all others. That, of course, is Murphy’s law, which states “Anything that can go wrong will go wrong.” At times it seems that Murphy’s law applies irrespective of whatever attempts are made to circumvent it. Actually, that is not the case at least for PCB design.

 

The most important parts of your PCB are the components upon which rests the ability of your board to perform its function. Despite their importance, PCB component failure is an often overlooked part of design that can result in erratic behavior, circuit and system failure or damage to the environment in which they are deployed. For example, premature failure of a critical pacemaker component may result in loss of life.  Because of their critical importance, we as designers should take all possible steps to prevent PCB component failures or to provide workarounds that may prevent a tragedy from occuring. Before laying out some ways to avoid tragedy, let’s look at reasons why PCB components fail.

Why Do PCB Component Failures Occur?

Circuit boards can fail. Let’s first get that fact straight. They can! Regardless of how comfortable or secure you are in your design capabilities. There might be a faulty solder joint or a solder bridge, your electronic components might have an error in their construction. Maybe your design software failed you somewhere along the way and your printed circuit is not adhering to the rules you wanted it to be following.

 

There are many reasons for PCB component failures most of which can be traced back to errors in part manufacture, board design or board manufacture. Some of the more common causes of failure along with the most likely source are listed below.  

 

COMMON PCB COMPONENT FAILURES

PCB Component Failure

Description

Cause

Exceeding electrical tolerances

Voltage or current outside the operating range of the component.

Usually due to poor design

Poor component quality

Component performance not up to specifications

Poor component manufacture

Contamination

Excess debris from manufacturing that can lead to failures in component bonding

Lack of adequate cleaning during board manufacture

Mechanical shocks

Board exposed to excessive vibration, bending or other mechanical stress

Adequate testing not done to verify flexibility

Environmental reasons

Lack of heat dissipation, extreme exposure to cold

Application environment conditions exceed board tolerances

Age

Product lifecycle exceeding component lifecycle

Natural fatigue or breakdown of component materials

 

PCB component failure may have other causes, such as electromigration or the gradual breakdown and movement of contact material, which can lead to lack of connection for integrated circuits (ICs). However, those listed above are the most common. Regardless of the source, PCB component failures inevitably lead to tragic results for the board itself and likely the system in which the board is deployed.

How to Workaround the Tragedy of PCB Component Failures

When a PCB component fails in the field the impact can be quite significant. Depending upon the root cause of the failure, the board may need to redesigned. This means recalling products from customers and replacing them with the newly designed and manufactured parts. Although, the costs associated with recall and replacement can be staggering PCB component failures can lead to even dire consequences.

 

For example, critical component failure in medical, aerospace, military or automotive systems could lead to expensive system failures or even loss of life. The most common ways to avoid such contingencies are the use of high quality components, routine testing to verify operational readiness and real-time alerts. However, as Murphy’s law asserts there will be times when these safeguards will not be sufficient.

 

 replacing a PCB component

Replacing a failed PCB component

 

Whether due to urgency or to limit excessive repair costs, in circuit workarounds can be deployed to provide a quick, effective alternative in the face of tragedy caused by PCB component failure. Workarounds are backup or alternative designs that can be instituted in the field to continue to normal system operation or provide additional time until repair or replacement can be done. Effective workarounds include the following:

  • Plug and play parts -  components where the pins plug into a pad as opposed to be soldered directly onto the board provide a quick and easy way to replace a malfunctioning component.
  • Redundancy - adding duplicate components such that the signal path can be rerouted if one component fails is a very effective workaround. Circuit operation and performance should not suffer and it can be done quickly using manual switches.
  • Jumpers - jumpers provide an external way to change the internal configuration of a component. This can be used to workaround internal component malfunctions without any replacement.

All of the above workarounds require that the designer consider the probability of PCB component failure at some point during the board’s deployment lifetime. Although instituting workarounds does mean additional design time, design restrictions, possibly additional components, and increased development cost the savings after a tragedy has occurred will most likely justify the initial expenditures.

 

PCB component failures are a significant problem that inevitably lead to tragic results. Board failures can require costly recalls and redesign and for sensitive applications such as medical, aerospace, military or automotive systems the results can even be fatal. Therefore, it is incumbent upon the designer to provide workarounds that can lessen the impact of component failures and possibly save lives.

 

In order to create robust designs to avoid tragedies associated with PCB component failures the best PCB design and development software package is required. Thankfully, Altium offers a user-friendly, cheaper design software alternative that still has strong design software functionality. Outside of just PCB layout, Circuitstudio even provides you with schematic generation capabilities!

 

For more information on how to add PCB component failure workarounds into your design, talk with an Altium PCB design expert.

 

About the Author

Altium Designer

PCB Design Tools for Electronics Design and DFM. Information for EDA Leaders.

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