How to Spot a Counterfeit Electronic Component

A visual field guide from AERI's lab: the indicators we use to identify counterfeit, remarked, and used electronic components, with real examples of parts we have caught.

A note before you start. I have written this from years of inspections at our own facility, and from my work on the industry committees that set the rules for this. I am a founding member and former committee chair of the SAE AS6081 standards committee. My goal here is simple: to show you what we actually look for, so you can inspect with more confidence, whether you ever send a part to us or not. Please share it with anyone you do business with. The more buyers who know what to look for, the harder this gets for the counterfeiters.

Why does counterfeit detection matter, and where do these parts come from?

It has become necessary for every distributor of electronic components, and every manufacturer who builds with them, to inspect incoming parts for authenticity. You cannot assume a part is genuine because it arrived on a reel, in manufacturer packaging, with a certificate of conformance. Counterfeiters reproduce all of those.

Counterfeit electronic components have historically been most prevalent in parts that trace back to mainland China. We avoid purchasing from unauthorized sources in that region, and we still receive counterfeit parts regularly. That is the part most buyers find surprising. Often the counterfeits reach us through long-standing, good-faith suppliers who simply are not trained or equipped to catch them. The fake does not announce itself, and an honest supplier passes it along without knowing. That is exactly why inspection cannot be skipped on open-market parts, no matter how much you trust the person you bought them from.

The rest of this guide walks through what we inspect, roughly in the order we inspect it, from the packaging down to the silicon inside the part.

What tools do you need to detect counterfeit components?

You can start with less equipment than people expect. Here is the baseline.

First, all the standard tools for handling electrostatic-sensitive parts, because the inspection should never be what damages the component. Second, a microscope with at least 30X magnification, and ideally a camera built into it. The camera matters more than it sounds: several of the steps below involve sending photographs to the manufacturer or to another resource for a second opinion, and you cannot do that without images. Third, a solvent to test marking permanence. Acetone is the common choice and will tell you quickly whether a marking has been applied after the fact. A less harsh option is a mix of three parts mineral spirits to one part alcohol. That second mixture is not arbitrary: it is the solution that MIL-STD-883 (method 2015.13) requires a genuine part marking to withstand without coming off. So if a marking wipes away utilizing it, the part fails a military test standard, not just our opinion.

What should you check during incoming visual and packaging inspection?

Before anything goes under the microscope, inspect the packaging and the markings with your eyes. A surprising number of counterfeits give themselves away here, because the counterfeiter focused on the part and got careless with the paperwork. Look for:

Misspellings on the manufacturer's labels. Real manufacturers do not misspell their own part names or company names.
Date codes on the label that do not match the date codes on the parts themselves.
Date codes that are not physically possible. A code like 0657 is a giveaway, because date codes run year-then-week, and there is no week 57. Valid weeks run 01 through 52, occasionally 53.
Date codes in the future.
Missing moisture-sensitivity protection. If a part is moisture sensitive, it should arrive in a dry pack with a humidity indicator card. Counterfeiters frequently forget one of the moisture-sensitive requirements.

None of these alone proves a counterfeit, but each one is a reason to slow down and look harder.

How do you read the indents (mold cavities) on a plastic IC?

This is our number one external method, so I will spend the most time here. Most plastic integrated circuits have small cavities, or indents, created during the molding process. Some are pin-one or other placement designations; others are just artifacts of the mold. A genuine mold cavity is clean and consistent. Counterfeiters have a very hard time keeping the indents clean and consistent when they refinish a part, because their resurfacing process fills, distorts, or fakes those cavities.

Two counterfeit X2212P ICs from one lot showing mismatched mold indent counts and shapes — Two X2212P parts received in the same lot with identical part-number markings. These are the same ends next to each other: one has three indents, the other has two, and the shapes differ as well, one a rounded cavity and the others flattened.

Stacked SHARP LH5116-10 chips showing an indent filled by blacktopping resurfacing — Differences in the indents again, on two SHARP LH5116-10 parts sharing date code 0223 9EB. The lower-left indent looks similar, but the middle-right indent is not apparent on the bottom part. This happens because counterfeiters sand the parts down to remove the old markings, then resurface them with blacktopping, which often fills shallow cavities.

Close-up of a counterfeit HD61602R indent filled to the edge with blacktopping material — A close-up of an HD61602R indent that has been filled in with blacktopping material. These indents are never partially made during manufacturing; they are uniform in depth throughout the circle. This one is filled to the edge on one side.

Counterfeit OP279GP indent filled and uneven compared with a clean manufacturer cavity — Indents are always clean and uniform from the manufacturer. This OP279GP indent has been filled in with the material used to cover up the old surface.

Counterfeit UPD70320L-8 with a circle etched to fake a molded indent, visible under microscope — The counterfeiters are figuring out that we catch their mistakes, so they have started trying to add an indent so all the parts look uniform. To the naked eye this looks like a regular indent. Under the microscope it is easy to see that the circle on this UPD70320L-8 was etched, not molded.

National Semiconductor DP8304BN with paint inside the mold indent, a counterfeit indicator — The manufacturers we speak with are strict about their standards. Paint is not where it is intended to be inside an indent, so paint in the indent on this National Semiconductor DP8304BN is suspect for counterfeit.

Counterfeit DP8304BN from the same lot code showing one oversized indent and one missing — Another DP8304BN from the same lot code as the part above, with a further problem in the indents: one is much larger and another is non existent. Where there is no single smoking gun we look for more than one clue, and here two fairly obvious anomalies make the determination clear.

Counterfeit DAC1006LCN indent marked AP — This one reads as an "AP".

Counterfeit DAC1006LCN indent with a swirl marking — A swirl-shaped mark inside the indent.

Counterfeit DAC1006LCN indent with a hooked marking, third of three patternless variants — A "U" mark.

These three DAC1006LCN parts are all marked identically on top, but the indents carry completely different markings. Some variation can be legitimate, since a real part might carry two letters that differ part to part, but markings that follow no consistent pattern across identically marked parts are a strong counterfeit signal.

Why does the country of origin matter on a part with the same lot code?

Most parts large enough to carry a country of origin display it somewhere on the package, often in the indents. (Smaller parts sometimes encode it inside the lot code, which makes it less useful as a single deciding factor.) Here is the rule that makes this powerful: we have confirmed with the component manufacturers directly, and every one of them tells us the same thing. A part with a given lot code cannot have been manufactured in two different countries. The lot code ties a part to one facility and one production run. So if two parts share a lot code but name two different countries of origin, at least one of them is not what it claims to be.

Two counterfeit A5841SLW parts with the same lot code, one indent marked PHILIPPINES and the other MALAYSIA — Two A5841SLW parts with the same top markings and the same lot code. The indent on the left reads PHILIPPINES. The one on the right is marked MALAYSIA, though the blacktopping has made that writing unclear. A close-up of that blacktopping problem appears in the texture section below.

MC68332ACFC16 parts with identical lot codes, one indent stamped USA and the other MALAYSIA — The same impossibility on an MC68332ACFC16, and easier to read here. Same lot code on top, but the left indent is stamped USA and the right is stamped MALAYSIA.

How do you detect blacktopping from the surface texture?

Blacktopping is the heart of most remarking. The counterfeiter sands off the original marking, applies a coating ("blacktop"), and remarks the part. The texture of the surface is where that process leaves evidence, and most of it is invisible to the naked eye, so this is microscope work.

Plastic electronic components are typically made with a mix of fine glass and plastic, so the surface of the molded package is textured when it comes out of the mold, while the pin cavities are often very smooth. Counterfeiters have developed a good mixture for recreating a similar surface on top of the original one, and with the naked eye it is almost impossible to tell the difference. Under a microscope there are many signs.

Microscope view of a genuine molded IC surface with sharp glass-filled texture, used as the reference baseline — Start here, because you cannot recognise a fake surface until you know what a real one looks like. Through a microscope a true surface has a sharper, duller look: the glass in the molding compound creates sharp little peaks and valleys. Blacktopping smooths those over and fills them in, like putting a coat of paint on sandpaper. This applies to most parts but not all; some legitimate parts have smooth plastic finishes with no glass in the mixture. Every image that follows should be read against this baseline.

Microscope comparison of a bubbly resurfaced counterfeit surface beside a gritty matte genuine surface — A side by side at high magnification. On the left, a resurfaced counterfeit surface: bubbly, glossy, and uneven. On the right, a natural package surface: gritty and matte. Surface texture is the first thing we check under the microscope.

Blade scraping a blacktopping coating off a counterfeit part, top side coated and bottom side bare — The top of this part carries blacktopping and the bottom does not. A single scrape with a blade lifts the coating off the surface, exposing the original markings it was hiding, often a different part number, date code, or manufacturer.

Two counterfeit Infineon SAF-C517A-LN parts with identical external markings hiding two different internal dies — Two parts marked identically as Infineon SAF-C517A-LN, with the same date code, lot code, and logo. Decapsulation showed two completely different dies inside. One is the part the customer ordered. The other is a relabeled commercial-grade part.

Microscope view of directional sanding marks on a counterfeit BTS443P surface, circled in red — Focus on the directional sanding marks circled in red on this BTS443P. Parts coming straight out of a mold will not have marks with a directional pattern. These are made when the counterfeiters sand off the top or bottom markings to prepare the part for blacktopping. You need a microscope to see this; it is not visible to the human eye.

Counterfeit MAX743CPE showing directional sanding marks from remarking preparation — The second of the two sanding examples, on a MAX743CPE. The same directional working of the surface is visible here.

HD61602R edge showing a shiny blacktopped top surface against a duller original finish — Often if you look at the edge of the part you can see the change in texture from the blacktopping. The top of this part is shiny and the bottom has a duller finish. These parts are made in a mold, and molds are not designed to put a shiny finish on the top. The texture should not change halfway across a section of the part.

Counterfeit UPD70320L-8 with a faked etched indent whose interior texture does not match the surrounding surface — The more samples you see, the easier it gets to tell an original surface from a fake one. The glare on the main surface here points to a high possibility of blacktopping, because the fine glass and plastic a mold produces does not shine like this. This is another indent created to fool the naked eye: the error in the etched circle is visible, and the texture inside the circle is neither smooth nor similar to the rest of the part.

Counterfeit HD61602R showing two different surface textures within one area — This shows two different textures in one area. It is not uncommon to see a smooth finish in the indent and a textured finish on the face of the part, but you should never see two different textures within one area of the part.

Counterfeit M54459L with remarking material stuck inside the mold indent — Remember that the indents should be clean. The reason they are not uniform on this M54459L is that during the remarking process the material gets stuck in the indents. Any extra material in an indent does not belong there.

Counterfeit SST28F1040A showing a stamp applied over an existing country-of-origin marking inside the indent — A similar case on an SST28F1040A-120-4C-NH, where a stamp appears to have been applied over an existing one inside the indent. Re-stamping like this is most often done to cover a different country of origin underneath.

Counterfeit MAX500BCWE indent half filled with blacktopping, showing textured lettering — As described above, the indents are typically smooth, so the writing inside them should not be textured either. This MAX500BCWE is an extreme example, with half the indent filled by blacktopping material, but any lettering that carries texture is most likely blacktopped.

Counterfeit HD61602R 3E3 with an over-sanded sloping edge from remarking — On the top-left of this HD61602R (marked 3E3) the sander went a little too far, creating a downward-sloping angle that none of the other parts in the lot had. It is common to see an edge slightly rounded; a sanded slope like this is not.

One of our most striking finds. The very shiny, smooth, orange-peel finish on this CY7C344-25 did not look natural. We scraped the thick blacktop off and found an Altera logo under the Cypress marking.

Two HSP50016JC-75 lots compared, one showing blatant blacktopping — Another part with blatant blacktopping, next to one carrying the exact same lot code with a legitimate surface. Worth noting the rare exception: we reported this to a supplier who buys primarily from the original manufacturer's obsolescent excess, and investigation showed the part on the left had actually been resurfaced for the manufacturer. A factory mis-mark, upgrade, or downgrade can be legitimately remarked. It is very rare, but it does happen, which is why we look for more than one clue.

How do solvent tests reveal a remarked part?

The tools section mentioned solvents for checking marking permanence. This is where they pay off. A genuine marking is laser-etched or applied to withstand handling and solvents. A counterfeit marking is usually printed on top of the blacktop coating, so it comes off.

HSP50016JC-75 after an acetone wash on one side, revealing a top coat over the molded plastic — An HSP50016JC-75 after an acetone wash on the right-hand side. It is very obvious that there was a top coat over the molded plastic, and a marking underneath is now partly exposed. If you wash a part with one of these solutions and see a different texture, or the marking wipes off, you can be fairly certain you have a counterfeit.

Suspected counterfeit TC58FVT160AFT-70 before solvent test at the pin one indent — BEFORE: a TC58FVT160AFT-70 we suspected of being counterfeit, at the pin-one indent. Note the textured but shiny black finish.

Same TC58FVT160AFT-70 after acetone wash showing light sanding marks and the original surface beneath the coating — AFTER: the same part after being washed with acetone. You can see some light sanding marks, but the surface now looks much more like the original surface of a legitimate part.

What marking imperfections signal a counterfeit?

Every manufacturer we have spoken with holds quality standards that preclude major imperfections. Part numbers belong in a certain location on the part and should not be crooked, misspelled, or out of alignment. Logos are monitored closely and should not vary from part to part. Markings are made to withstand tough environments and stay legible. When markings break those rules, it is a red flag.

Counterfeit BTS443P AP601 with marking hanging off the edge, misaligned versus the rest of the reel — Manufacturers state that markings should sit in a proper area of the part. This batch of BTS443P / AP601 parts on a reel had the markings in a slightly different area on each part, and this one missed the part on the left-hand side.

Counterfeit ISO118UB with a 3 etched in place of a B and extra etching errors — On this ISO118UB the character on the far left is supposed to be a "B" and has been etched as a "3." We also noticed extra etched marks toward the top, filled with the same color used to display the part number.

Counterfeit MAX4616CSD marked on top of a mold indent, confirmed unacceptable by Maxim — This MAX4616CSD is marked on top of the indent, which the manufacturer has informed us is not acceptable from their production. Maxim confirmed these are counterfeits, and we have seen this marking error on more than one occasion.

Counterfeit MAX252BCHL with the marking running into the mold indent — Here again the marking is not where it should be, running into the indent on this MAX252BCHL. The manufacturers will tell you they do not allow this in their production.

This SI4888DY was on a manufacturer's labelled reel of 2,500 pieces. The old etched Allegro Microsystems logo was very hard to see with the naked eye, let alone through the foggy tape. We pulled some out because this supplier did not have the best history, and found the old etching had been blacktopped over and etched again with the new part number.

M54459L whose marking wiped off under the MIL-STD-883 solvent test, revealing a counterfeit — The marking on this M54459L was very crisp and clear. The leads looked a little used, but the markings looked straight out of the manufacturer and the surfaces looked legitimate, so the only remaining visual check was marking permanency. We used the MIL-STD-883 mixture of three parts mineral spirits to one part alcohol, and the part number wiped right off.

Maxim MAX459CQH with an etched marking and date code 0033, illustrating Maxim paint-versus-etch dating — The markings wiped off this part easily as well. One thing to note about Maxim in particular: they have not marked their parts with paint since at least before 2002, they only etch. That did not help us here because this MAX459CQH was made in 2000, but if you receive a painted Maxim part with a date code newer than 2002, you have a counterfeit.

When should you inspect internal characteristics with decapsulation and X-ray?

Counterfeiters have gotten much better at the external work, so for high-reliability applications it becomes important to inspect the internal characteristics of the part. The equipment and personnel for internal testing are more advanced and therefore more costly. The two most important internal evaluations are decapsulation, to confirm at least one die in the lot is correct, and then X-ray inspection of a large sample of the balance of the lot to confirm the whole lot is the same. We run both in our own in-house lab.

Confirmation of a part through decapsulation. The exposed die markings, here a Samsung die, are compared against the manufacturer's known die to confirm authenticity.

X-ray comparison of two parts with the same lot code showing different internal die and lead frames — Suspect counterfeit example: X-rays of two parts that carry the same part number and lot code but show different internal characteristics. Same markings, different insides, means at least one is not genuine.

How does XRF confirm the lead and material composition?

Another helpful process for confirming a part's authenticity is identifying whether the leads are constructed with the correct material. Counterfeit parts can be re-tinned to cover up previous use, or constructed with a different material because the part is not the part as marked. This test is performed with an XRF analyzer (X-ray fluorescence), and we compare its results against the manufacturer's specification.

XRF analyzer spectrum report showing lead-finish elemental composition for counterfeit screening — An example report from our XRF analyzer, showing the lead, copper and tin peaks. We compare the measured composition against the manufacturer's specification; a mismatch in the lead-finish alloy is a reliable indicator of re-tinning or a substituted part.

How does spotting fakes fit into a full counterfeit prevention strategy?

Detection is half the picture. Knowing what a counterfeit looks like protects you on the parts you happen to inspect. Keeping counterfeits out of your supply chain in the first place takes a system: a receiving process, a way to qualify the distributors you buy from, and the right level of testing for the risk of the application. We wrote a companion guide on how to build a counterfeit prevention strategy and qualify an independent distributor, and it pairs directly with this one. If this page showed you the "what," that guide is the "how."

The visual checks here also map onto how testing is tiered. The external and solvent inspection in this guide is the baseline (an IDEA-STD-1010 level inspection, the most widely accepted open-market inspection standard in the industry). Decapsulation, X-ray, and XRF are the elevated work you add as the consequence of a failure rises, up to full AS6081 and AS6171 protocols for mil-aero parts. AERI tests to AS6171 standards, with the specific checks scoped to the risk level of your application, rather than running every test method on every part.

Frequently asked questions

How do you spot a counterfeit electronic component?

Start with the packaging and markings: misspellings, mismatched or impossible date codes, and missing moisture protection. Then inspect the part under a microscope at 30X or higher for blacktopping signs, including directional sanding marks, inconsistent surface texture, and filled or faked mold indents. Test marking permanence with acetone or the MIL-STD-883 solvent. For high-reliability parts, add internal checks: decapsulation to confirm the die, X-ray to confirm the lot matches, and XRF to confirm the lead-material composition.

What is blacktopping on an electronic component?

Blacktopping is a remarking technique where a counterfeiter sands off a part's original markings, applies a coating over the surface, and prints new markings on top. It is detectable under a microscope through directional sanding marks, a surface texture that differs from a genuine molded finish, filled mold indents, and a top coat that dissolves or wipes off under solvent, often revealing the original marking or a different manufacturer's logo underneath.

What magnification do you need to inspect for counterfeit chips?

A microscope of at least 30X magnification, ideally with a built-in camera. Many counterfeit indicators, such as directional sanding marks and texture inconsistencies, are not visible to the naked eye. The camera lets you document findings and send images to the manufacturer or another resource for a second opinion.

Can a date code tell you a part is counterfeit?

Sometimes, directly. Date codes run year-then-week, so a code such as 0657 is impossible because there is no week 57 (valid weeks are 01 through 52, occasionally 53). Future date codes and date codes on the label that do not match the parts are also red flags. A valid date code does not prove authenticity, but an impossible one is strong evidence of a counterfeit.

Why does decapsulation matter for high-reliability parts?

Counterfeiters have become very good at external remarking, so for applications where a failure cannot be recovered, external inspection is not enough. Decapsulation chemically removes the package to expose and verify the die against the manufacturer's known die. It is destructive, so it is run on a sample, then paired with X-ray inspection of a larger sample to confirm the rest of the lot matches.

How does XRF detect a counterfeit component?

XRF (X-ray fluorescence) identifies the elemental composition of a part's leads and package. Counterfeit parts are often re-tinned to hide prior use, or built from different materials, so the lead-finish alloy does not match the manufacturer's specification. Comparing the XRF reading to the spec reveals that mismatch.

Is a part automatically counterfeit if it has been resurfaced?

Almost always, but not quite always. In rare cases a manufacturer legitimately resurfaces or remarks its own parts (a factory mis-mark, upgrade, or downgrade). Because that exception exists, a responsible inspection looks for more than one independent indicator before declaring a part counterfeit, rather than condemning it on a single clue.

About the author

Robb Hammond is the founder and president of AERI (American Electronic Resource, Inc.), an independent electronic component distributor he started in Costa Mesa, California in 1994. He is a founding member and former committee chair of the SAE AS6081 standards committee, which governs how independent distributors detect and avoid counterfeit electronic components. The inspection methods in this guide come from 32 years of catching counterfeits in AERI's own lab, where inspection is performed by IDEA-ICE-3000 certified inspectors and AERI holds AS6081, AS9120/ISO 9001, and DLA QSLD and QTSL qualifications (CAGE 08YR5).