Issue link: https://resources.pcb.cadence.com/i/1545328
When Your Component Is Unavailable: Alternates, Last Buys, and Counterfeits 13 www.cadence.com Figure: (Source: KiarashKevin86, CC BY-SA 4.0) Authentic Intel flash memory IC (right) compared to a counterfeit replica (left). Although the external packaging appears identical, X-ray imaging reveals significant differences in the internal die structure. XRF (X-ray fluorescence) Detects: elemental composition of the lead finish and package material. Can identify re-tinned leads (lead finish does not match manufacturer specification), wrong package material, and in some cases missing or substituted elements in the package compound. Does not detect: die characteristics, electrical parameters, or remarking that does not alter the material composition of accessible surfaces. Practical use: effective for detecting re-tinned reclaimed parts and verifying RoHS compliance of lead finish. Less useful for detecting cloned or remarked parts where the package material is unchanged. XRF equipment is not commonly available in design engineering departments. It is typically found in component engineering labs, EMS facilities, and specialist test houses. Many independent distributors offering component authentication services include XRF as part of their inspection scope. Electrical testing Detects: gross parameter failures, functional non-conformance, and parts that fail at electrical limits. The most effective non-destructive method for detecting substandard components when the test covers the rated operating limits, not just nominal conditions. Does not detect: parts that meet initial electrical specifications but will fail under extended use, thermal cycling, or radiation exposure. Cloned parts that approximate the original device's DC parameters but have different AC behavior or reliability characteristics may pass standard electrical test. Practical use: always include worst-case condition testing, maximum rated voltage, minimum and maximum rated temperature, maximum rated current, not just nominal condition testing. A parametric test at nominal conditions gives false confidence. Destructive testing note: decapsulation (removing the package to inspect the die) is the definitive test for distinguishing a cloned or remarked part from a genuine one. It requires specialized equipment and destroys the part. For small quantities of high-risk components, commissioning decapsulation testing on a sample from the suspected lot, even at the cost of a few units, is justified. The cost of a field failure or a production yield problem caused by counterfeit parts typically far exceeds the cost of destructive testing.