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An older date code is a reason to investigate a semiconductor lot, not a complete reason to accept or reject it. Calendar age, moisture exposure, lead condition, and traceability are different variables. A purchase policy that collapses them into one cutoff can reject usable material while missing poorly handled recent stock.
This article covers packaged semiconductors. It does not extend the same conclusions to batteries, electrolytic capacitors, adhesives, or other components and materials with different aging mechanisms.
Texas Instruments’ 2021 long-term storage evaluation reports results for devices stored in an environmentally controlled setting, including several package and finish types. Its earlier component reliability study also examined device and packing-material behavior.
These studies support a limited conclusion: age alone is an inadequate proxy for the condition of every semiconductor. They do not certify a broker’s lot, establish unlimited storage life, or eliminate application-specific handling requirements. Both documents were accessed on September 15, 2026.
Apply the study to the actual material only after comparing package construction, terminal finish, storage conditions, and inspection scope. “TI tested old parts” is not a release criterion for unrelated stock.
Four independent acceptance questions
| Question | Evidence to request | What it does not establish alone |
|---|---|---|
| Is the material what it claims to be? | Source records, original labels, lot linkage, agreed authenticity checks | Fitness for solder assembly |
| Has storage preserved the package and packing? | Storage history, bag seals, carriers, contamination and corrosion observations | Electrical conformity |
| Is moisture exposure controlled? | MSL, opening history, humidity evidence, approved drying records if needed | Authentic origin |
| Will terminals support the intended assembly? | Finish-specific inspection and solderability evaluation where justified | Complete device reliability |
The date-code verification article concerns identity and marking evidence. A correct code is useful, but it is not a substitute for the remaining three questions.
Sealed storage and floor life
Shelf storage concerns time in the applicable storage environment. Floor life concerns permitted exposure after moisture-sensitive material is opened under defined conditions. Do not transfer a limit from one concept to the other.
Record the actual package’s moisture sensitivity level and handling instructions. Review whether the bag is original, whether it has been opened, whether seals are intact, and whether the exposure record is credible. A humidity indicator is evidence within that history; it is not a reconstruction of every prior handling event.
For detailed exposure assessment, use the MSL and receiving guide. Any drying or baking decision should match the device, carrier materials, and applicable procedure. Avoid a blanket bake for all old inventory.
A condition-based verification plan
A controlled plan should identify the lot, package and finish, failure concerns, sample selection, test methods, and acceptance limits. Visual inspection can reveal damaged leads or contamination. Electrical tests address defined functions and limits. Solderability evaluation addresses the ability of terminations to form an acceptable joint under the chosen method.
Those checks answer different questions. Passing one does not justify claiming that the entire lot is free from every latent defect. Where material has mixed histories, sampling only the best-looking package may not represent the remainder.
If the storage record is incomplete, document the gap and the evidence required to resolve it. Some applications may reject material with that uncertainty even if a sample performs correctly; other programs may permit a controlled deviation. The responsible engineering and quality functions should define that boundary in advance.
Write a useful age policy
Replace an unexplained “date code under two years” request with the actual requirement where the customer permits it: approved source, acceptable storage history, package condition, traceability, and agreed verification.
When a customer or program explicitly imposes a date-code restriction, retain it until the responsible party approves a change. A general research article cannot waive a contractual requirement.
For an obsolete-component quotation, communicate exceptions before placing the order. State whether mixed date codes are allowed and whether acceptance depends on further testing.
Long-term support of industrial equipment benefits from a documented disposition: accepted lot and quantity, conditions of use, storage actions, records reviewed, and remaining restrictions. That is a more useful result than labeling every older device “expired” or “as good as new.”
Frequently Asked Questions (FAQ)
Do semiconductor devices expire after two years?
There is no universal two-year expiration rule for all semiconductors. Acceptability depends on the device, package, finish, storage and exposure history, condition, and application requirements.
Can baking restore an old component to new condition?
No. A suitable drying process can address specific moisture conditions, but it cannot restore missing traceability, reverse every form of corrosion, repair ESD damage, or prove electrical conformity.
Does a fresh date code establish good material?
No. Recent manufacture does not establish correct storage, authentic origin, or suitability for a particular application. Date code is one part of the evidence.
