Obsolete and hard-to-find parts: source them without buying fakes
When a part goes EOL, the remaining stock is finite and the price stops following the catalogue. Most of the risk is in how that leftover stock was stored and described.
First, work out which kind of “obsolete” you have
There are three different situations and they need different answers. EOL means the manufacturer has stopped making it and has issued an end-of-life notice, usually with a last-time-buy date. PCN means a process change — different package material, different fab, different marking — but the part is still made; often you do not need to change the BOM at all. Allocation means the part exists but is being rationed, which is a supply problem, not an obsolescence problem.
Ask the supplier which one it is, and ask for the notice number. A supplier who cannot tell you is guessing.
Where leftover stock actually comes from
Genuine obsolete stock usually comes from cancelled projects, excess inventory at contract manufacturers, and distributors clearing their last reels. It is real, and it is often the best option for keeping a product in production. The same channels also carry refurbished parts that have been cleaned and re-marked, and parts pulled from scrapped boards.
The tell is rarely visual. It is the combination of date code, packaging, quantity available and price. A part that has been EOL for six years, available in exactly the quantity you need, at a price below the last catalogue price, deserves suspicion.
What to verify before you commit
Date code and packaging. Ask for the date code in writing and a photo of the label. Check that the packaging matches the age — a 2018 date code in a freshly printed bag is a contradiction.
Moisture history. For fine-pitch SMD parts, ask whether the moisture-barrier bag was still sealed. Parts stored badly can pass a functional test and fail in reflow.
Testing. For critical or expensive parts, budget for decapsulation, X-ray or curve tracing. It is the only way to catch re-marked parts reliably.
Consistency. If you need 5,000 pieces, ask whether they are one date code or mixed. Mixed batches are workable but must be declared, because they change your process window.
When to stop searching and redesign
If the part is safety-related, if the remaining stock is one unknown batch, or if the price has moved beyond what the product can carry, redesign is cheaper than the risk. A cross-reference to a current part usually costs one prototype run; a bad batch of obsolete parts can cost a recall.
Our rule: we will quote obsolete stock with the date code and condition stated, and we will tell you when we think you should redesign instead.
Frequently asked questions
Often yes, through excess inventory and distributor stock. We confirm the date code, packaging and quantity available before quoting.
Common parts can be confirmed in a day; rare ones may take several days of searching. We tell you quickly when a part cannot be found.
Original surplus exists, but so do refurbished and re-marked parts. We state the condition and date code, and can arrange third-party testing on request.
Yes. If the stock is unknown, mixed or priced above what the product can carry, we will say so and suggest a cross-reference instead.
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