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Low Cost Electrical Test for Counterfeit Device Detection
Seawave, a timing diagram of a functional test program in process.
By Tom Saven, VP — Network Marketing and Terry Harvell, Engineering Manager — Diagnosys, Inc.
It's a dilemma faced frequently. When we take our car for repair, our mechanic can choose between factory replacement OEM parts or their lower priced alternative. We are told that third party parts are manufactured to the same rigid standards as the OEM version, but at a fraction of the cost. That can mean saving hundreds of dollars on our repair bill. It makes you wonder what the OEM does differently from the third party vendor to justify the higher price. Or maybe, it is what the third party supplier fails to do that cuts costs to permit a lower selling price.
In some cases, the real difference is due to tighter or looser tolerances in physical dimensions. Sure, the mounting points are the same or the parts will not fit properly, but the life of the part may be compromised from the lack of quality control. In other cases, inferior base materials reduce initial costs that translate into a lower selling price.
There seems to be no debate in the Electronic Parts Supply Chain as to the seriousness of counterfeiting issues. It is huge, to the tune of an estimated $600B annually according to some US government agencies. The problem is clearly defined. There is no debate even in the bipartisan Senate and House committees assigned to address this concern. No inventory, no matter how vigilant the owner has been, is considered pure at this stage.
Some counterfeit products are not as easy to identify. They hide in plain sight.
The Supply Chain and the Risk Mitigation planners are very watchful. A variety of processes, techniques and guidelines has been put in place over the last four to five years. Parts Distributors and OEM's alike are deploying groups of people to address the counterfeiters. Yet many of these techniques are based around some form of optical inspection. Does the device appear to be in original packaging? Under magnification, does the plastic appear altered?
These non-contact, non-destructive testing methods can help identify counterfeit components to a degree. They can flag packages that do not visually look close enough to the OEM version. What happens when the markings and plastic begin to look perfect? The packaging appears original? When the known source inventory is infiltrated?
Visual examination methods are part of a comprehensive counterfeit component identification solution, but cannot stand-alone. One form of counterfeiting comes in the form of reclaimed components being sold as "New" when in fact they could be damaged internally and defective in ways that visual examination will not detect.
Physical examination of the package, using x-ray, scanning or other optical techniques will give you an indication if the package is empty, or if the die connects to the lead-frame. Yet this type of examination falls short of confirming the functionality of the component.
Other methods include limiting your sources or utilizing curve trace comparator systems. Again, there is consensus in the Supply Chain that no single technique or method is adequate on its own.
Genuine and counterfeit components look identical. The difference is in the actual performance.
Many distributors own considerable inventories of legacy parts. Some of it dates back to the early 1980's. Older parts may be visually imperfect and rejected on their appearance alone although needed by manufacturers.
To be confident that a device is genuine and working correctly requires more than a physical inspection. You must check the chips functional performance. "When people think of functional test, they think of the big iron test platforms and the associated cost of ownership," states Tim Webb, President of US Operations for Diagnosys Systems. "The evolution of functional test brings this capability to a bench-top size and the simplicity of a cell phone."
So how can we properly identify the genuine component?
Technology is readily available to provide Counterfeit Detection Solutions for a comprehensive range of components. Implementing automated device verification as part of your incoming materials inspection can prevent counterfeit parts from making their way into your production stream.
Dynamic electrical test provides an in-depth validation of a devices' functionality by applying power to the device and running a series of test vectors in a specific sequence and monitoring that the outputs respond accordingly. Developing vector-based tests using component manufacturer's data sheets ensures accuracy of the routine. All test parameters can be stored in a device profile as a test routine that can be used over-and-over again. The key to making functional test a successful part of your incoming inspection is the ability to add functional test programs quickly and efficiently as needed. Good systems offer a standard library that may typically contain over 50,000 pre-written test routines. The supplier should offer a service to create new routines to accommodate additional components as required or the software should allow user defined programs.
Performing dynamic electrical tests on a device requires a method of supporting the chip and creating reliable electrical connections between the chip and tester. A universal Interface adaptor provides support for common package types such as DIP, PLCC, PGA, SOIC and QFP. A flexible DUT board adapter would allow for future adaption of virtually any package type including BGA.
At least one range of testers offers test rates of up to 20 million digital vectors (test patterns) a second for a very thorough and in-depth test on devices. For analog mixed signal IC's, embedded instruments needed include waveform generators, digital oscilloscopes, switching matrices, digital multi-meters, an LCR bridge and more. Integrated instrumentation provides a synchronized analog-digital test capability that is fully automated within the test routine. Rapid application, switching and measurement of analog signals deliver accurate and reliable test results.
Another method to compliment the vector based test approach is Impedance Signature Analysis often referred to as curve tracing. An impedance signature is created by applying a voltage (V) and measuring current (I) on a pin of a known good IC. This technique is known as VI (or V-I) testing. It is an effective technique for detecting certain types of failures, but cannot test the functionality of a device. It also relies on the availability of a known good device as a golden part. This technique has proven to be useful when looking for potential ESD damage or when functional test is not an option.
Implementing automated device verification as part of your incoming materials inspection can prevent counterfeit parts from making their way into your production stream. Just remember to include visual and functional testing to ensure that your components are genuine and worthy of going in a product with your name on the outside of the box.
Counterfeit parts are a reality that is here to stay. It is up to the product manufacturer to determine genuine parts from fakes. While there are a number of methods available to identify counterfeit parts, none stand-alone as a golden bullet. It takes a dedicated effort and multiple validation techniques to confirm genuine, good parts enter the assembly flow. More and more companies are turning to affordable functional test as it takes the guesswork out of the equation and gives them the security and peace of mind that what they have is both genuine and working.
Contact: Network Electronic Marketing, 5719 E. Indian School Rd., Phoenix, AZ 85018,
480-994-8242 fax 480-990-9599 E-mail: firstname.lastname@example.org; or
Diagnosys USA 5 Lan Drive, Westford, Massachusetts 01886,
800-788-6219 or 978-392-0406, fax 978-392-3622 E-mail: email@example.com Web:
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