FAQs
Common questions about semiconductor obsolescence
What is semiconductor obsolescence?
Semiconductor obsolescence is when an electronic component, integrated circuit or device is no longer manufactured or readily available from its original source. This can happen when a manufacturer discontinues a part, stops supporting older technologies, exits a market, or consolidates product lines after an acquisition or merger. For long-life systems like aerospace, defence, rail and industrial platforms, semiconductor obsolescence can create serious challenges because the equipment may still need to be manufactured, repaired or supported long after the original components have reached end of life.
What is the difference between functional and technical obsolescence?
Functional obsolescence is when a system, platform or component is no longer used or practical to use, because it doesn't meet the needs of the user, align with modern standards or practices, or may not do all the things it did when it was new. It may still work — at least to some extent. Technical obsolescence is when a product or system is outdated by a newer model. This is common in consumer electronics. A system may still work, but newer models are released with additional or different functionality.
What should I do when an electronic component becomes obsolete?
First, you need to know how critical the part is to the system. Assuming it is important, you'll need to investigate what stock is still available, and whether there are approved alternatives. You'll also need to know whether you are only able to use franchised parts, or if grey market components are acceptable. For most aerospace, defence and rail applications, grey market sourcing is restricted or requires additional approval. Depending on stock availability, you may be able to invest in a last-time buy, or bridge buy. Other options include alternative sourcing with component verification and reliability testing, upscreening of a commercial or industrial component, redesign, or a form, fit and function replacement. Ideally, review the components on the board early and plan ahead so you have time and space to make a considered decision.
What is an LTB?
LTB can refer to "life-time buy" or "last-time buy". In both instances, this is when a significant quantity of semiconductor components or die is purchased to support a long-life platform. The nuance between "life-time" and "last-time" is about the overall availability. A manufacturer may offer a "last-time" buy of components before they stop making them. A "life-time" buy is when a procurement team decides to buy as many components as are projected to be needed for the full lifecycle of a platform. This could also be triggered by an end-of-life notification. In both instances, components then need to be stored in a secure, temperature and humidity controlled, inert environment, to ensure the components remain reliably functional for years or even decades into the future. Another term used is "bridge-buy". This refers to purchasing an amount of devices to cover the projected demand until a board redesign is scheduled or an alternative component is qualified for use.
Can I still use a component after it has been discontinued?
In many cases, a discontinued component can be used, if stock is available. However, be aware of the risks of counterfeit components. Look for traceability, storage history and handling conditions, and get the authenticity checked if you have any concerns. For defence and aerospace applications, look for testing in line with AS6171 requirements.
How do I know if an electronic component is counterfeit?
Counterfeiters are getting better. Indications that a component may be counterfeit or have been altered include inconsistent markings, poor packaging, incorrect or missing documentation, physical damage such as scratch marks, resurfacing, altered date codes, unexpected electrical behaviour, or they may not function in the same way as known-good samples. Visual inspection is important, but electrical testing and destructive physical analysis are also often an important part of the testing.
What is die banking?
Die banking is when a semiconductor die is stored in its lowest-level format (i.e. unpackaged), so it can be assembled into a packaged component later. This is a cost-effective way of managing the obsolescence risk because the upfront investment is for the die and storage, not for every single assembled component. You can then receive brand new product with consistent characteristics, on an agreed schedule.
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