How to Test Suspect Electronic Components

Electronic components drive nearly everything in our modern lives, but as long as there are buyers for parts, counterfeiters will try to stay in business. Financial losses due to fake components are difficult to verify due to inability to enforce and difficulty gathering data on the problem. It is likely that under-reporting occurs and this casts a further shroud on this complex issue.

The problem is large enough that some assemblers and warehousing operations might consider adding component testing capabilities and services to identify fakes before assembly. In some cases, ordering from overseas demands a “trust but verify” approach, where the receiver takes steps to inspect and test high value components. If your operation is considering adding this capability, here is how to go about testing and verifying components in batch orders.

How to Quickly Test and Inspect Parts Batches

Batches of electronic components can contain thousands of individual parts. Sometimes these are packaged in tape and reel, sometimes in trays, and sometimes in tubes. Depending on the size of a batch and the number of different components involved, as well as component types, it may not be possible to test every single component in a PCB.

Before we look at specific test and inspection procedures, think about some of these high-level points as you develop a testing plan:

• Focus on the highest risk parts, such as costly integrated circuits

• Focus on repackaged parts as the repackaging may indicate tampering

• Focus on parts procured outside of authorized channels

• For large batches, take a statistical approach and select a meaningful sample size

With this in mind, let's look at some simple test and inspection procedures that can identify most mishandled or fraudulent components.

Packaging Inspection

The first place for inspection component packaging, specifically the storage and shipping packaging. Components should be properly packaged such that they are protected from environmental exposure and can be stored long-term. This involves use of moisture barrier bags, desiccants, ESD-safe materials, and correct dates on packaging. Improper packaging materials or reused packaging materials could be an indicator of mishandling and could demand deeper inspection of the components.

Repackaged components that have been vacuum sealed will have a clear mark where the heat from the sealer was applied

If packaging does not appear to be correct, some further inspection or remediation might be required. Sometimes, packaging problems will be obvious; parts thrown into a cardboard box are obvious examples of mishandling. Some closer inspections on the components directly may be needed, parts might need to be baked based on their MSL, and some parts might even need to be tested electrically.

Physical Inspection

Once unpacked, a visual inspection of parts is also necessary. Make sure to check several points on the packaging which could be indicators recycled components or faked components:

• Part number

• Date code

• Lead quality

• Presence of corrosion

• Any damage or markings on packaging

• Smudged markings

All of these points can be inspected visually with a magnifying glass or a microscope, and some can even be inspected automatically with an optical system.

Parts that don't pass physical inspection will typically have obvious defects, such as missing labels, missing date codes, old date codes, or extreme corrosion. Most often, this is associated with recycled or reclaimed components. If the parts are still suspect, there are some non-destructive tests and functional testing.

Non-Destructive Tests

This refers to a class of possible testing mechanisms that can help identify defective parts without destroying a component under test. The most common method for inspecting components that uses readily available equipment in PCB assembly facilities is X-ray inspection. With an X-ray machine, the presence of a die can be seen in the components package. One approach is to compare this to a die from an authentic component, although this may be difficult if the resolution on an X-ray system is too low. However, if a component passes this test then it may not require further inspection or testing.

There are more advanced imaging techniques that can be used to identify and profile a semiconductor die in a package. Unfortunately, these are out of reach for most PCB assembly house operations, and these techniques require specialized training. X-ray imaging is fast enough and accurate enough to quickly look through a small sample size and qualify a component batch.

Test Circuits

Another option for testing incoming components is to build a fixture with a test circuit. Some data sheets provide example test circuits that can be used to verify a component is authentic and functioning correctly. An example for Texas Instruments part number UCC5350 is shown below.

These test circuits always need to be custom built, usually on perfboard or a breadboard, and then connected to an automated test program. Doing this quickly and at scale requires some special training and software, so there is a time investment required to build and program these fixtures. The level of detail they can collect is also up to the developer and the time available for testing; simply checking pin output levels is much simpler than monitoring pins over time.

Test fixtures will give the best results, but because of the investment involved they should be reserved for the highest value and highest risk components. Specialized ASICs with no replacements and certain processors are potential candidates for evaluation with a test circuit. Some RF components, such as off-the-shelf modules or PCB-mount components, could also be tested with automated fixtures, although the test and measurement equipment required to do this can be very expensive.

RF filter modules like this bandpass filter can be tested with automated test equipment

If you want to avoid the headache of maintaining a testing and QC program for your parts, make sure you stick to the authorized distributor channels. Authorized distributors, or direct procurement from manufacturers, will eliminate the need for these testing procedures. To help you find the parts you need for your builds, make sure you use the right data source with complete supply chain visibility.

The next time you need to look for reliable sources for electronic components in your BOM, head over to Octopart and use the advanced search and filtration features to create your component orders. You will also find suggested alternates on Octopart’s component pages and up-to-date distributor pricing data, parts inventory, and parts specifications.

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