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When Your Component Is Unavailable: Alternates, Last Buys, and Counterfeits 11 www.cadence.com 4.1 Which Components Are Most Commonly Counterfeited Not all components carry equal counterfeit risk. The categories most frequently reported in ERAI and similar databases are: f Integrated circuits: particularly microcontrollers, FPGAs, power management ICs, and analog chips from major manufac- turers. These have high unit values, are frequently in shortage, and are difficult to verify without electrical testing or destructive analysis. Counterfeit ICs include remarked parts (a lower-grade or different speed grade version of the part relabeled as the higher grade), reclaimed parts (removed from used boards and re-tinned), and clones (a different die sold under the original part number). f Power MOSFETs and transistors: high-value discrete semiconductors that are difficult to verify electrically without applica- tion-specific test setups. Counterfeit MOSFETs often meet basic electrical parameters but fail under thermal or high-current conditions. f Memory ICs: DRAM, NAND flash, and NOR flash are commonly counterfeited because demand is high, shortages are frequent, and basic electrical testing does not always reveal substandard parts. Counterfeit memory often passes initial electrical test but exhibits higher error rates or reduced endurance over time. f Passive components: MLCCs and resistors are less commonly counterfeited for their part number but are frequently subject to specification misrepresentation, a lower-rated component sold as a higher-rated one. The CALCE research center at the University of Maryland identified counterfeit MLCC capacitors in which a costly dielectric element (yttrium) was missing from the dielectric layer, undetectable by visual inspection and standard electrical test. 4.2 The Four Types of Counterfeit Part Understanding what category of counterfeit you may be dealing with determines what testing is useful. Type Description and detection implications Remarked A genuine component with the part number, grade, or date code altered. Often a lower-speed, lower-temperature, or lower-quality variant of the claimed part. May pass basic electrical testing but fail at rated conditions. Decapsulation can reveal the original die marking. XRF can sometimes detect date code remarking. Reclaimed / refur- bished Parts removed from used PCBs, re-tinned, and re-marked. The component may function initially but has unknown prior usage history and may have accumulated damage. Lead inspection and solderability testing often reveal inconsistent plating. X-ray can show solder residue from previous mounting. Cloned A different device manufactured to approximate the claimed part's behavior, sold under the original part number. May pass functional test at nominal conditions but fail at electrical limits or over temperature. Decapsulation reveals a different die. Curve tracing, if available in your test environment or through a component engineering lab, may reveal subtle parameter differences at electrical limits. Substandard A component manufactured to lower specifications than claimed. Includes components that fail to meet the rated temperature range, voltage rating, or reliability grade. Common in passive components. XRF can detect material composition issues. Electrical testing at rated limits is the most effective detection method.

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