Lifecycle Status: Active, NRND & EOL#

Every electronic component has a lifecycle that follows a predictable arc: introduction, active production, maturity, decline, and eventually obsolescence. Understanding where a component sits on this arc is essential for making design decisions that avoid scrambling for replacements in two years. The lifecycle status of a part is as important as its electrical specifications — a perfect part that is about to be discontinued is a ticking time bomb in any design.

The Component Lifecycle#

Introduction. A new part is released by the manufacturer. It may have limited stock, limited application note support, and limited field history. Early adopters get the newest features but take on the risk of errata, limited supply, and possible design changes before the part stabilizes.

Active. The part is in full production. Stock is generally available at major distributors, the manufacturer is investing in application support, and the part appears in reference designs. This is the sweet spot for design-in: the part is proven, supported, and available.

Mature. The part has been in production for years. It’s well-understood, widely used, and has extensive application support. Stock may be high because production has been running for a long time. However, the manufacturer may be developing a replacement, and attention is shifting away from this part.

NRND (Not Recommended for New Designs). This is the critical warning signal. The manufacturer has decided to phase out this part, but it’s still being manufactured — for now. Existing production is supported, but the manufacturer is telling new designers: don’t build this into a new product. The part might continue to be available for months or even years, but the end is coming.

EOL (End of Life). The manufacturer has announced a last-time buy date. After that date, no more will be produced. Customers can place final orders, and after the last shipment, the part is gone. EOL announcements typically give 6-12 months of notice, but some are shorter.

Obsolete. Production has ended. The part is no longer manufactured. Whatever inventory exists in the distribution chain is all that’s left. Prices rise, availability becomes sporadic, and the counterfeit risk increases as brokers source from less reliable channels.

How to Check Lifecycle Status#

Lifecycle information isn’t always easy to find, and it’s scattered across multiple sources:

Manufacturer websites are the authoritative source. Most major semiconductor manufacturers (TI, Analog Devices, STMicroelectronics, NXP, Microchip) include lifecycle status on their product pages. Look for labels like “Active,” “Not Recommended for New Designs,” “End of Life,” or “Obsolete.” Some manufacturers use different terminology — learn each one’s vocabulary.

Distributor product pages often flag lifecycle status with icons or labels. Digi-Key marks parts as “Active,” “Not For New Designs,” “Obsolete,” or “Last Time Buy.” Mouser uses similar flags. These are derived from manufacturer data but may lag behind official announcements.

Product Change Notifications (PCNs) are formal documents from manufacturers announcing changes to a product — including discontinuation. For registered customers or those with an account on the manufacturer’s notification system, PCNs arrive by email. Many distributors also forward PCNs to customers who have purchased affected parts.

Component databases and lifecycle trackers (like SiliconExpert, IHS, or Octopart’s lifecycle data) aggregate lifecycle information from multiple manufacturers. These services are aimed at professional design teams and often require paid subscriptions, but they provide comprehensive, searchable lifecycle data.

Engineering communities and forums. Sometimes lifecycle information surfaces informally before official announcements — a field application engineer mentions that a part is being phased out, or a discussion thread reveals supply problems that presage an EOL announcement. This isn’t a reliable primary source, but it’s useful for early warning.

The NRND Dilemma#

NRND is the trickiest lifecycle status because it requires a judgment call. The part still works, it is still available, and it may continue to be available for years. But the manufacturer has signaled that it is winding down.

For new designs: avoid NRND parts. The manufacturer is explicitly advising against using them. Design in the recommended replacement, even if it requires circuit changes. The short-term inconvenience of adapting to a new part is far less than the long-term cost of redesigning when the NRND part reaches EOL.

For existing products already in production: evaluate the risk. How long will the product be manufactured? What is the production volume? Can enough inventory be stockpiled to cover the remaining product lifetime? Is a redesign to a new part economically justified?

For prototypes and one-offs: NRND parts are usually fine. When building five boards for a lab experiment, the part’s lifecycle does not matter. But if the prototype might evolve into a product, consider the lifecycle implications early.

The trap: using an NRND part because “it will be fine for our timeline” and then having the timeline extend. Projects that were supposed to ship in six months ship in eighteen. Products that were supposed to be short-run become long-run. The NRND part that seemed temporary becomes a dependency that cannot be escaped.

Planning for Obsolescence#

Obsolescence is not an exception — it is a certainty. Every component will eventually be discontinued. The question is not whether parts will go obsolete, but whether the design team will be prepared when they do.

Design for substitution. Use standard packages, standard interfaces, and circuit topologies that work with multiple components. This is covered in detail in Designing for Substitution, but the key principle is: don’t paint yourself into a corner with a unique part that has no alternatives.

Maintain an alternate BOM. For every critical component, document at least one alternate part number with notes on any design changes required. When the primary part reaches EOL, a ready-made plan for substitution is already in place.

Monitor lifecycle status actively. Do not wait for the EOL announcement to discover that key parts are being phased out. Set up notifications with manufacturers and distributors. Review the BOM’s lifecycle status at least annually.

Consider last-time buys carefully. When an EOL is announced, there is the option to buy enough inventory to cover remaining production needs. This requires estimating future demand, accounting for storage degradation (especially for electrolytic capacitors and moisture-sensitive devices), and tying up capital in inventory. It is a business decision, not just an engineering decision.

The Lifespan Mismatch#

One of the most fundamental tensions in electronics design: a product’s lifespan may be much longer than its components’ lifecycles.

A medical device might need to be serviceable for 15-20 years. An industrial control system might be in production for a decade. An automotive ECU must be available as a replacement part for the life of the vehicle platform, which can be 10-15 years. But the semiconductor components inside these products may have lifecycles of 5-7 years.

This mismatch forces either: periodic redesigns to replace obsolete components (expensive but ensures continued availability), strategic inventory purchases to stockpile parts for the product’s lifetime (ties up capital and risks degradation), or designing with deliberately conservative, long-lifecycle parts from the start (limits performance but reduces obsolescence risk).

The automotive and military/aerospace industries have developed formal frameworks for managing this — long-lifecycle component programs, qualified component lists, and formalized obsolescence management processes. For smaller companies and individual designers, the same principles apply at a smaller scale: be aware of the mismatch, plan for it, and build in flexibility.

Tips#

• Check lifecycle status on the manufacturer’s product page before committing any new component to a design — distributor labels can lag behind official announcements
• Register for Product Change Notifications (PCNs) with manufacturers and key distributors to receive early warning of NRND and EOL transitions
• Maintain an alternate BOM for every critical component so a ready-made substitution plan exists before a last-time-buy deadline arrives
• Review the full BOM’s lifecycle status at least annually to catch parts quietly drifting toward NRND or EOL

Caveats#

• NRND status is not always prominently displayed. Some manufacturer websites bury lifecycle status deep in product pages or only show it in the ordering system — never assume a part is active just because the product page exists
• “Active” does not mean “available.” A part can be in active production but allocated, with lead times of 30+ weeks; active status guarantees ongoing manufacturing but not immediate availability
• EOL announcements can be sudden. While most manufacturers provide 6-12 months of notice, some give less, and small manufacturers or niche products may announce EOL with minimal warning
• Obsolete parts attract counterfeits. When a popular part goes obsolete and demand persists, counterfeit parts appear in the gray market; use only authorized channels and consider testing incoming parts for authenticity
• Last-time buy quantities are hard to estimate. Buy too few and the supply runs out before the product ends production; buy too many and capital is wasted on parts that sit on a shelf
• The “recommended replacement” is not always a drop-in. When a manufacturer discontinues a part and suggests a replacement, the replacement may have different pinouts, different electrical characteristics, or different package options