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Cloned ICs: Better Specs Than Authentics

When I worked as an engineer for a manufacturer of semiconductor production equipment, purchasing would often ask us to provide second sources for various ICs. For those parts that had second sources, we would test the parts to verify that second-source parts met expected specs before deciding if the parts would work for us.

Parts such as 74xxxx series logic devices and common op amps have long had such second sources available from authorized manufacturers and distributors. Fake parts—those removed from scrap boards and sold as new—have been a common problem for many years. In recent years, however, a new class of fakes—cloned parts—has appeared in the supply chain. In some cases, these clones have been found to have some specs that are better than those of authentic parts.

Tom Sharpe,
SMT Corp. VP

On December 12, Tom Sharpe, VP of SMT Corp., spoke to a gathering of the Boston, New Hampshire, and Providence chapters of the IEEE Reliability Society about cloned parts. Sharpe gave an even more detailed presentation to the National Security Agency (NSA) the previous week.

Sharpe opened by showing what SMT was seeing in 2012 and followed by what's coming out of China today. The presentation was based on tests performed at SMTs labs. SMT is a distributor specializing in obsolete parts, stocking nearly 500 million parts, much of which is sold into the defense sector.

“We saw first cloned devices appear in 2012, said Sharpe, “starting with the MAX232. At that time, we had only heard about cloned parts and they were slipping into the supply chain undetected. That year, SMT found nineteen different cloned parts affecting eight original component manufacturers (OCMs), all major manufacturers. Today, we see over 150 cloned parts representing 31 OCMs.”

Sharpe clarified the difference between a clone and what was originally called a counterfeit part. “Prior to 2012, we were seeing reworked parts that had been removed from e-waste circuit boards being sold as new, but they were generally authentic parts (EBN's sister publication EDN reported on such activities in 2011). A clone, however, is made entirely by the counterfeiter, from the ground up. The counterfeiter has complete control of the cloned parts design and manufacture. “Many IC companies are fabless,” he continued. “They may not even be aware that the fabs making their parts are also making clones.” Sharpe added that he was not aware of any “ghost fabs” making cloned parts.

In 2012, SMT started seeing what Sharpe called “Functional die emulation” where the cloned part functioned well at room temperature. Upon investigation, SMT found that the die inside the package was completely different from that of an authentic device (Figure 1).

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Figure 1. A cloned device (right) had a completely different die than an authentic device, yet was functionally equivalent. Click image to enlarge.

While functional equivalents are one thing, Sharpe noted that later in 2012, SMT began to see cloned parts where even the mask of the authentic part had been copied. “They even did a one-third die shrink,” he noted.

To make matters worse, some cloned parts exhibited better performance than authentic parts . SMT engineers tested ten samples of an authentic shift register and ten cloned samples of the same device. Figure 2 shows test results indicating a better high-voltage variation among the cloned parts. “The counterfeiter actually took the time to dial in this spec better that the OCM.” That statement drew a chuckle from the audience. Sharpe said the cloned parts were likely made with newer technology than the older authentic parts, hence the better test result. Sharpe gave another example of a Schmitt Tigger where the cloned part outperformed the authentic part by having a wider hysteresis. Other test such as performance over temperature may show that the cloned parts are inferior, though Sharpe didn’t discuss that. A significant difference between early counterfeit parts and today's clones is that these counterfeit parts are made from scratch in clean rooms. 

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Figure 2. A sampling of ten cloned and ten authentic shift registers revealed better performance by the clone, at least for this parameter. Click image to enlarge.

Cloned parts are not the only problem. Sharpe noted a situation where an authentic part had been tampered. It was an obsolete part purchased on the open market for a defense contractor. SMT engineers identified the part as a possible fake because of the packaging quality. Digging deeper, they found that the counterfeiter needed to gain access to the die to erase the programming. Sharpe believes that the intent here was to sell the part as a new blank. 

Telltale signs
Early suspected cloned parts could be identified by their inferior packaging, but that's no longer the case, explained Sharpe. In Figure 3, you could argue that the cloned MM74C923 (bottom) looked better than the authentic Fairchild part. The counterfeiter even copied the “drip” in the center of the “MM” in the part number. 

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Figure 3. By 2016, Cloned Parts were looking better packaged than authentic parts. Click image to enlarge.

In 2017, SMT was asked to test 20,000 pieces of a supposed Altera device used to program FPGAs on power-up. After parts had passed electrical tests, Engineers looked at the packages, which showed no rework and every mechanical dimension was within manufacturer's specs. These were new parts. 

Telltale signs
Early suspected cloned parts could be identified by their inferior packaging, but that's no longer the case, explained Sharpe. In Figure 3, you could argue that the cloned MM74C923 (bottom) looked better than the authentic Fairchild part. The counterfeiter even copied the “drip” in the center of the “MM” in the part number. 

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Figure 3. By 2016, Cloned Parts were looking better packaged than authentic parts. Click image to enlarge.

In 2017, SMT was asked to test 20,000 pieces of a supposed Altera device used to program FPGAs on power-up. After parts had passed electrical tests, Engineers looked at the packages, which showed no rework and every mechanical dimension was within manufacturer's specs. These were new parts. 

Figure 4 reveals differences in the substrate. Sharpe said he believed that the manufacture of the part was originally STMicro, but Altera took that over. The cloned part's die said “Miami.” Clearly, it's not identical. Another part's die said “Chicago.” 

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Figure 4. A cloned Altera (originaly STMicro) part (top) clearly has a different die than the authentic part (bottom). Click image to enlarge.

Despite the differences in die, all parts in a lot of 200 “Miami” parts passed electrical tests at room temperature. 

The “Chicago” devices appeared in the supply chain a few months after the “Miami” parts. Electrical tests showed that both the “Miami” and “Chicago” parts, purchased on the open market, performed better than authentic parts acquired from reputable distributors. In fact, the cloned parts erased their programming at least ten times faster than authentic parts. Active mode power-supply currents for “Miami” were 3x smaller than authentic parts with “Chicago” parts coming in at 1.7x smaller(Figure 5). 

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Figure 5. Cloned parts draw less current then authentic parts. Click image to enlarge.

SMT is still testing parts beyond room temperature. Once that's complete, the company will report the results to the U.S. Government. 

Cloned parts are yet another threat to the supply chain. But cloned parts are manufactured by counterfeiters and they're good enough to pass visual inspections and functional tests. Some are even better that authentic parts. If counterfeiters have that much control, they could prove to be security risks. They could even be designed to fail. Some people might be willing to take a risk of using cloned obsolete parts because the cost of a board spin to accommodate a replacement part might not be worth doing, especially for small quantities. 

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Martin Rowe covers test and measurement for EDN and EE Times. Contact him at martin.rowe@AspenCore.com Circle me on Google+  Follow me on Twitter Visit my LinkedIn page

1 comment on “Cloned ICs: Better Specs Than Authentics

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    December 29, 2018

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