Product Change Notice: How to Read It and What to Do Next

What a PCN Actually Contains

A well-structured PCN from a major manufacturer will contain the following elements. Knowing where to find each one speeds up the triage process significantly.

PCN identifier and date: a unique reference number and the date of issue. This is your record for the change management file.

Affected part numbers: the specific manufacturer part numbers covered by the change. Watch for wildcards: a PCN may list a part number stem (e.g. XX1234-*) that covers dozens of variants. Always check your BOM against the full affected list, not just the headline part number.

Nature of the change: what is actually changing. This is the most important section. It describes whether the change is to the manufacturing process, the materials, the package, the specification, or the product's availability.

Reason for the change: why the manufacturer is making it. Common reasons include process improvement, supply chain consolidation, environmental compliance, or commercial rationalisation.

Effective date: when the change takes effect. Stock manufactured before this date uses the old specification; stock after uses the new one. This matters for incoming inspection and for assessing lot dates on any secondary market stock.

Customer response required by: the deadline by which the manufacturer requires you to confirm receipt, raise objections, or place a last-time-buy order. Missing this date has real consequences.

Qualification and sample availability: whether pre-production samples of the changed product are available and how to request them for re-qualification.

The Five Types of Product Change: Why the Type Matters

Not all PCNs are equivalent. The type of change described determines how much engineering assessment is required before the changed product can continue to be used.

Process change The manufacturing process changes, typically a wafer fabrication site transfer, a back-end assembly (OSAT) change, or a change to the test methodology. The electrical specification remains the same on paper. In practice, a process change can affect parametric performance subtly, particularly for analog and RF devices. Whether re-qualification is required depends on the application criticality and the customer's change control requirements.

Material change The materials used in the component change, most commonly a lead finish change (e.g. transition to lead-free terminations), a substrate material change, or a die attach material change. Material changes can affect solderability, thermal resistance, and long-term reliability. A lead finish change is particularly relevant for products still using tin-lead solder processes.

Package change The physical package changes: a new body moulding compound, a revised marking layout, a package dimension change within tolerance, or a change to the tape-and-reel specification. Package changes often appear minor but can affect pick-and-place compatibility and incoming inspection verification.

Specification change A datasheet parameter is being revised: a voltage rating, a temperature range, a timing parameter, or a maximum rating limit. Specification changes require engineering assessment to determine whether the revised specification is still adequate for the application. A tightened maximum rating is not always conservative: it may reflect a genuine capability change.

Discontinuation (EOL) The product is being discontinued. This is the most urgent PCN type and is sometimes issued as a separate PDN (Product Discontinuation Notice). It will include a last-time-buy date and a last-time-ship date. This is the notice that requires the fastest and most structured response.

How to Check Whether a PCN Affects Your BOM

The first task on receiving any PCN is to determine whether any of the affected part numbers appear in your active BOMs. This sounds straightforward but has several traps.

Manufacturer part numbers in PCNs are often listed with wildcards that cover variant suffixes for package type, temperature grade, and tape-and-reel versus tube. A PCN listing "LM358*" covers the LM358A, LM358AN, LM358D, LM358DR, and every other variant. Your BOM may list only one of these. Check the stem, not just the exact number.

Also check against the distributor order codes you actually use. Some purchasing teams order under distributor-specific part numbers that are not identical to the manufacturer part number. Verify that the underlying manufacturer part number is not in the affected list.

Finally, check not just the current revision of your BOM but any BOM variants for regional products, legacy products still in aftermarket service, and products in development that have not yet entered production.

Changes That Require Re-qualification

Whether a PCN change requires formal re-qualification before the changed component can be used depends on whether the change affects form, fit, or function.

Form covers the physical characteristics of the component: package dimensions, land pattern, marking, and mechanical interface. A package body change that alters a critical dimension requires assessment of PCB footprint compatibility.

Fit covers how the component interfaces with adjacent parts and the assembly process: pad size, solderability, component height, and pick-and-place compatibility. A lead finish change falls here.

Function covers the electrical behaviour: whether the component still performs its intended role in the circuit to the required specification. A process change that subtly alters an analog parameter may constitute a functional change even if the datasheet specification is unchanged.

In automotive (IATF 16949), a form, fit, or function change requires a new PPAP submission. In medical and aerospace, the equivalent change control processes apply. In general industrial applications, the threshold for formal re-qualification is set by the customer's quality agreement. When in doubt, treat any process, material, or specification change as requiring engineering assessment before approving the changed part for production use.

When a PCN Is Really a PDN: Reading the EOL Signal

Manufacturers do not always issue a separate PDN. Some issue a PCN that includes last-time-buy information alongside the change description, effectively merging the two notices. Others issue a PCN for the last-time-buy and a separate final notice for the last-time-ship.

The signals to look for: any mention of "last time buy," "last order date," "product discontinuation," "end of life," or "no further orders accepted after." These phrases in any PCN field mean the product is being discontinued, regardless of whether the document is titled a PCN or a PDN.

When you identify an EOL signal, the priority shifts immediately. The question is no longer whether re-qualification is needed. It is how much of the original component you need to sustain production and aftermarket requirements through the end of your product's service life, and whether the last-time-buy window gives you enough time to place that order.

The Response Window: What Happens If You Miss It

PCNs include a customer response date for a reason. After that date, the manufacturer considers the change accepted and may begin shipping the changed product without further notice. For an EOL notice, the last-time-buy date is a hard cutoff: once it passes, the manufacturer accepts no further orders at any price.

Missing a last-time-buy window does not mean supply is impossible. It means authorised supply is gone. Any stock available after the LTB date exists only in distributor inventory or the secondary market, in quantities that deplete and do not replenish. That is a manageable situation with the right sourcing partner, but it is a more constrained and more expensive situation than acting within the LTB window.

How Maketronics Helps When the PCN Arrives

When a PCN signals a last-time-buy or an EOL event on a component on your active BOM, Maketronics can help you assess the secondary market availability of the original part, identify what verified stock exists and at what price levels, and structure a sourcing approach that covers your production and aftermarket horizon.

For components where the LTB window has already closed, our sourcing process evaluates every lot for authenticity, date code consistency, and lot integrity before we make a recommendation. For higher-risk requirements, Maketronics Assurance provides independent inspection with a pass/fail recommendation before shipment.

Received a PCN or PDN on a component on your live BOM? Talk to the Maketronics team and we will tell you what the supply picture looks like and what your options are.