When Your Component Is Unavailable: Alternates, Last Buys, and Counterfeits
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4.3 What Non-Destructive Testing Can and Cannot Detect
Figure 4: No single test method catches every counterfeit type. Remarked and cloned parts in particular require multiple methods in
combination, and relying on visual inspection alone leaves the majority of counterfeit categories either partially detected or missed entirely.
The testing methods available to most engineering teams without specialized laboratory access are limited in what they can
detect. Understanding the limits of each method is more useful than a list of methods that suggests comprehensive
coverage.
Visual inspection under magnification (10x to 40x)
Detects: inconsistent or blurred markings, misaligned labels, sanding marks where original markings were removed, contami-
nation from prior use, inconsistent lead finish across a batch, and packaging anomalies (incorrect font, wrong country of
origin stamp, inconsistent tape-and-reel labeling).
Does not detect: any internal characteristic, correct electrical parameters, or sophisticated remarking using laser engraving
on genuine parts.
Practical use: always perform on incoming parts from non-authorized sources. Compare against a known-good sample from
authorized distribution. Inconsistency within a batch, variations in marking font, ink depth, or lead finish that do not appear in
parts from a single production lot, is a strong indicator of mixed or suspect inventory.
X-ray inspection
Detects: internal die structure, wire bond configuration, presence of solder residue from prior use, voiding in BGA balls, and
gross internal abnormalities.
Does not detect: electrical parameter deviations, remarking of the package exterior, or subtle die differences in cloned parts
where the internal structure is visually similar to the genuine part.
Practical use: most effective for BGAs and other packages where reclaimed part detection via solder residue is the primary
concern. Requires a reference image of a known-good part for meaningful comparison.
