Fighting against counterfeit electronic components requires many tools, including multiple test methods to identify the counterfeits. Use of improper or incorrect testing procedures can lead to incorrect or misleading results, at times identifying authentic parts as being counterfeit.
Over the past few years, new techniques of black top, remark, and resurface marking tests have been implemented to discover nonauthentic marking and coating processes that have been used on electronic components and devices. While these tests can be very effective at identifying counterfeit plastic components, the same tests can also yield false positive readings for ceramic-packaged devices that have not been blacktopped/coated or on can package devices that have not been resurfaced. Some of the experiences with false results from solvent testing were reported at the recent Components for Military and Space Electronics (CMSE) conference in Los Angeles, CA (February 2014).
In one instance, a hermetically sealed non-resurfaced) packaged device which was authentic failed Dynasolve testing, which indicated that it was a counterfeit part. The part in question was a model SNJ54HC4040J from Texas Instruments (www.ti.com) which failed Dynasolve testing that should have never been performed. The component was falsely identified as counterfeit according to the Dynasolve test.
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shows a TO can (non-resurfaced) packaged device that would fail mineral
spirits testing for authentic/counterfeit differentiation. |
In another example, a model LM158H from National Semiconductor, which is supplied in a can-type package, failed mineral spirits testing for authentic/counterfeit verification. The testing on the can (non-resurfaced) device revealed an authentic part to be counterfeit. The mineral spirits testing should never have been performed on this type of packaged component, which are notably those in TO housings, such as TO-3 and TO-8 can packages.
Another category are QML components, which are supplied in hermetic housings, such as ceramic, glass, or TO can packages. These packages and their markings should never have been subjected to acetone, M2P, or Dynasolve solvents since they are not designed to pass these tests in checking for counterfeit/authentic product validation. These solvents should only be used to test plastic-encapsulated-microcircuit (PEMS) housings for blacktopping that had been used to hide any remarking that has been performed.
Experiences in testing a wide range of packaged devices and components for authentic/counterfeit differentiation has helped identify some proper testing methods for different components. The first group of these testing "lessons" applies to a nonmilitary, non-printed-circuit-board (non-PCB) assembly solvent test for remarking and resurfacing according to SAE AS6081, paragraph 4.2.6.4.3 requirements. For example, experience in the use of scrape testing have been useful in early stage detection of resurfaced electronic devices and components. An industry recommendation is for the single-use application of a sterile cotton-tip applicator (6-in.) and wood shaft specimen data collection applicator.
The second group of these testing "lessons" applies to military and industrial non-resurfaced PCB assemblies, for marking permanency testing. Marking permanency testing is performed per the requirements of military standards MIL-STD-883 for microcircuits and MIL-STD-750 for semiconductors. These tests are recommended for use with components and devices in hermetic ceramic and can-type packages which show no evidence of resurfacing as well as for aerospace and military marking tests for other components and devices. Testing involves the use of bristle brushes with three long rows of hard bristles, fabricated from nonreactive materials for checking the resurfacing of the components and devices under test.
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| Effective scrape testing can help reveal resurfaced electronic components. |
The proper exercises and applications for the first and second groups of devices/components to be tested include performing marking permanency testing according to MIL-STD-883 and MIL-STD-750 requirements for the first group of devices and components, and performing a solvent test for resurfacing according to SAE AS6081 Para 4.2.6.4.3 for the second group of devices and components.
