Many engineering teams begin looking for possible failures as soon as they have a semiconductor design. Medium-to-large organizations typically have reliability engineers onsite who review design documents, bills of materials, test procedures, and manufacturing processes trying to find weaknesses that can result in product failure. Small companies or startups might use consultants. Reliability engineers try to find and analyze possible failure conditions (modes) to find out each failure’s severity and possibility of occurrence. “
The first thing you must do when developing a reliability plan is to define a deep failing, which can take one or two meetings. What exactly is a failure in a few circumstances could be not a deep failing in others. This will depend on the use case. For many semiconductor failures, a momentary interruption is tolerable, but not for other devices.
Failure analysis boils down to risk. Just how much chance of failure is acceptable depends on this product’s intended use cases while the consequences associated with failure. If lives or large sums of cash have reached stake, you will need to attenuate risk towards the greatest extent possible. Risk also will depend on the expected lifetime of an item.
Stress analysis is the most essential to perform, nonetheless it doesn’t cover everything. When designing circuits for reliability, many engineers utilize product reliability testing services to help with stress analysis testing.
The reliability testing service engineers have several tools and practices available for reliability planning and analysis.
- Stress analysis
- Mean time passed between failure (MBTF)/mean time for you failure (MTTF)
- Failure mode and effects analysis (FMEA)/Failure mode, effects and criticality analysis (FMECA)
- Worst-case analysis
We all know how temperature affects component and system lifetimes. Thus, stress analysis is, in several ways, thermal analysis. Thermal problems originate from too much heat generated by circuits along with inadequate cooling. Begin by calculating the voltage and current in each component, then calculate the dissipated power.
Temperature increases caused by heat dissipation may have an even more adverse effect on passive components and discrete semiconductors than on ICs. Temperature rise can not only affect a component’s time and energy to failure, nonetheless it can transform an element’s value, which can cause a board or system to functions away from its intended parameters.
Following stress analysis in circuit design comes MBTF/MTTF analysis. Many passive and active component manufacturers publish these data, separately for wafer fab and packaging. MBTF is basically according to historical data. While MBTF is a type of analysis performed on many designs (you need it for FMEA/FMECA), it may be error prone, according to Hymowitz.
A typical MBTF/MTTF analysis ranks parts to be able of shortest time for you failure. At that point, it’s a tradeoff among chance of failure, consequences of failure, and cost. Extending MBTF/MTTF often means paying for higher-grade parts. If you’re designing a satellite or other system where failure is paramount, you’ll likely choose parts using the longest MBTF. For, say, an mp3 player, cost usually takes priority, to a spot. Should your product is a method such as a network or manufacturing system that can’t be replaced in whole and downtime is an issue, then take mean time and energy to repair (MTTR) into consideration as well.
In recent repairs, the purpose of failure was always a capacitor. Capacitor manufacturers help you analyze MBTF by providing calculators similar to this one. The calculator plots a capacitor’s expected lifetime in an electrical supply according to temperature, DC voltage, and ripple (AC) voltage.