Electrical testing to detect counterfeit components

-August 28, 2012

Counterfeit electronic components are an increasing threat to the supply chain for consumer, industrial and, more importantly, military parts. Some counterfeit parts are like counterfeit money, unauthorized copies. Other cases include mislabeled parts where parts meant for one purpose are relabeled for another by changing the part number.

Specifically, parts built for consumer purposes can be illicitly changed, appearing to be suitable for the extreme rigors of military or aerospace use.  Even authentic parts with the correct model number can become counterfeit when they are improperly recycled and marked as new.

As the producers of counterfeit electronic components become more sophisticated in their methods,   it requires more detailed testing to spot the fakes. A similar device packaged and marked to appear as the correct device may even pass certain functional and parametric testing. A comprehensive set of tests includes such steps as validating the physical dimensions, testing the permanency of all markings, x-ray testing and electrical testing.  For example, New Jersey Micro Electronic Testing uses a variety of tests in its Mission Imposter® program to spot counterfeit electronic components.
Electrical testing over temperature is the industry standard for testing a component’s functional and parametric requirements at the recommended manufacturer’s or specific industry extreme operating temperatures. Electrical testing, the focus of this article, includes DC/AC functional and parametric testing over a range of operating temperatures. Electrical testing over temperature is the industry standard regarding testing the component device’s functional and parametric requirements at the recommended manufacturers or specific industry extreme operating temperatures.

The objective of electrical testing is to determine the quality of each product to avoid counterfeit distribution and production. This is accomplished by running a suite of tests or as many vital tests as possible to check the DC, AC, functional and parametric performance of the component in question. The intricacies of these tests can easily give test engineers a robust data set that they can use to uncover a counterfeit component where other test methodologies fail to uncover any problems or anomalies.

Comparing the data set that these tests yield to the limited data set provided by some of the newer electronic component testers on the market exposes the limited functions of these newer test instruments in uncovering counterfeit components.  These testers, to their credit, can easily detect early signs of counterfeit production but are limited in finding functional and parametric data and should not be viewed as a functional and parametric electronic component tester. For example, these new test devices only provide curve trace testing. Curve tracing tests each pin against a known good unit by exercising only pin-to-ground and pin-to-supply voltages and all pins can be grounded and each pin measured against other grounded pins. More complete testing with full functional and parametric data is required to fully qualify a component.

Figure 1. Typical curve trace exercise

Figure 1 shows a typical curve trace for a digital microcircuit. The curves indicate whether the pins are making contact to the device.  The top middle pane shows a pin that is not making contact; the other panes show pins making contact.

The more proper methodology of electrical testing is to use automatic microcircuit testers that can exercise multiple functional and parametric tests at one time to test the device properly in accordance with its port number requirements.

Automatic or automated test equipment (ATE)  is any apparatus that performs tests on a device under test (DUT), using automation to quickly perform measurements and evaluate the results. An ATE system contains dozens of complex test instruments (real or simulated electronic test equipment) capable of automatically testing and diagnosing faults in sophisticated electronic packaged parts or on wafer testing, including ICs and SoCs.

ATE is widely used in the electronic manufacturing industry to test fabricated electronic components and systems. It is also used to test avionics and the electronic modules in automobiles. It is used in military applications like radar and wireless communication, as well as in medical and industrial component manufacturing.

Another form of proper electrical testing is to use an instrumentation board or instrumentation interface between the electronic component, stand-alone test and measurement equipment and PC-based test and measurement equipment to provide specific functional and parametric testing. These tests are either made available by the component manufacturer or are custom designed by the test lab with the end-customer’s review and approval.

The initial connection is provided by parallel and serial interfaces, including the general purpose interface bus (GPIB). However, current technological trends require a more powerful interface, which is provided by implementing universal serial bus (USB), PXI, VXI and LXI/Ethernet ports.
Once a program has been generated and an instrumentation outline has been set up for the test, the device is then ready for electrical testing. All exercises will begin testing at room ambient temperature of approximately 25°C. Two accurate methodologies of testing electronic components under their extreme operating temperatures are to use a precision temperature forcing system (PTFS) or liquid nitrogen to accurately condition the component under test.

A PTFS (Figure 2) uses compressed forced air with custom-built test fixtures to maintain very cold temperatures as low as -100°C for a DUT as well as to maintain very hot temperatures of up to +300°C.

Figure 2. Illustration of a Precision Temperature Forcing System Preparing to Condition Components on a VLSI Test System
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