Best practice obsolescence management

Rochester Electronics explores the impact of market conditions on the military and aerospace supply chain, the long-term consequences and best practices to mitigate risk.

The extent of capacity issues in the semiconductor market first became clear as the world started emerging from the worst effects of the pandemic 15-months ago. The automotive market with its just-in-time, minimal stock, high volume demands was an early indication of problems to come.

Since then, supply chain disruption ripples have spread to all markets including the military and defence sectors.

Categorised by smaller (stop-start) batch production runs, with extended temp and special testing needs, component supply for the defence market was always at greater risk of being squeezed.

In its simplest terms, as fab capacity disappeared, lead times extended. However, other factors have also become apparent. As demand boomed for newer technologies/geometries, third-party fabs made the decision to announce the closure of older fabs. In many cases, this impacted product lines which had been regarded as ring-fenced ‘long-term secure’ technologies.

As original component manufacturers (OCMs) re-structured their production priorities with the capacity constraints they had, many chose to prune older product families, process technologies and package styles.

Increasing numbers of component discontinuations are a significant threat to the aerospace and defence markets as they have some of the longest production and service lives. It is not uncommon for production runs and service lives to be extended multiple times beyond the original planned service withdrawal dates, making it virtually impossible to accurately predict future needs.

So, with both short and long-term component availability more uncertain than ever, how do companies minimise these risks without creating new ones?
In an uncertain world, best practices include:

Dual sourcing: While it is rarely possible to approve multiple manufacturers for the same device, dual sourcing of authorised supply chains is essential.

Stock in the market: Ensure up-to-date visibility of all instantly available stock if supplies fail.

Advanced warning system: Share critical parts lists with trusted suppliers who can advise when: extended lead-times; natural disasters/acts-of-God; or market trends threaten supply chains. For example: A natural disaster affects production at a semiconductor plant—know within 48 hours which components are affected—see instantly available stock to prevent a line-stop—let suppliers provide pro-active rather than reactive support.

Track component lifecycles: Do not solely rely on lifecycle algorithms used by many online component tracking databases. Seek the support of an authorised end-of-life supplier/manufacturer to provide a second opinion. Many components correctly listed on these databases as ‘discontinued’ by the OCM are still in production from the authorised end-of-life sources, 10 to 20-years after formal EoL.

Companies need to establish a sourcing partner that can offer guarantees of availability over the long term and also demonstrate a controlled transition process through end-of-life and into long-term fully authorised supply—or even long-term production.

As an AS6496-compliant distributor and licensed manufacturer, Rochester Electronics continues to offer military grade semiconductors and packages long after the original OCMs discontinue them. In addition to the millions of components available in stock, Rochester’s in-house high-reliability hermetic assembly line offers a full complement of package styles including ceramic DIP, side brazed DIP, flat pack, CQFP, PGA, ceramic leadless chip carrier and metal can.

Rochester’s in-house qualification and test facilities ensure complete risk-free sourcing of components in compliance with industry standards. Rochester is a QML manufacturer certified by DLA Land and Maritime to MIL-PRF-38535 offering Class Q and Class V microcircuits for military and aerospace applications.

Products are manufactured using known-good-die stored in one of two nitrogen wafer storage facilities and are tested to AS6496 standards using the original test processes employed by the OCM. Products retain their original part number because they are guaranteed to meet the original datasheet specification. As a 100 per cent authorised source of supply, anti-counterfeiting standards that apply to independent suppliers such as AS6171 and AS6081 are not required.

For ongoing critical obsolete component needs, where Rochester does not hold available inventory or wafer to build, the company can leverage its test and design engineering experience to keep customers’ systems going.

Rochester can support fundamental design changes such as replacement of obsolete key components with ASIC solutions. Possibility exists in these cases to transition to an ASIC which is identical in terms of fit-form-function, with no software changes and no errata. This means aerospace DO-254 re-qualifications, even for safety-critical (DAL-A) applications, can be greatly simplified as a minor change.