Last Update - 08 Jan 2007

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Update - 21 Feb 2006
I have just been informed by the Australian supplier referred to below that these transistors are also branded as ON-Semi. The only way to be certain is to check the package. Genuine ON devices have square-edged steps on the pins, and (needless to say) have completely flat metal rear surfaces. The fakes have tapered pins and a stepped case as shown in the photo, and non-flat backs (although some may be 'better' than others).

The supplier has issued a recall of the ON branded fakes (having recalled the Motorola branded fakes as soon as they were alerted to the problem), but many constructors may have purchased the fakes before they were identified. If you find any transistors in your collection that look like the fakes shown below, return them immediately.

Update - 08 Jan 2007
A reader contacted me with some further information. He thinks that the reply from ON-Semi was not 100% correct. He has a couple of 25pc tubes of old stock, genuine, Motorola supplied, MJL21193/4 transistors which were bought several years ago through their major Australian distributor. They are date stamped the second and fifth week of 1999 respectively.

This contradicts the information from ON-Semi, which states that the manufacturer of these transistors with the Motorola logo ceased in 1998. The ON-Semi correspondent also states that Motorola hasn’t manufactured any semiconductors since 1998. That does not appear to be correct. Motorola was apparently still making PLL IC’s and RF power transistors after ON-Semi took over the majority of discrete component manufacture.

Based on this information, don't automatically discard genuine Motorola devices, thinking that they’re counterfeit just because of the date code.

The thing that gave the game away with these was the date code. According to the code, they were made by Motorola in 2000, but Motorola had handed all discrete semiconductor manufacture to ON-Semi in 1998, so a Motorola branded part allegedly manufactured after that date cannot possibly be genuine.

The same (or similar) fake devices are almost certainly still available in Australia, and can probably be picked simply by the price - I have heard AU$2.50 mentioned for small quantities. Since you can't buy the devices from ON-Semi for that, any MJL21193/4 offered for such a paltry sum is almost certainly counterfeit.

Photo of the Counterfeit 'Motorola' MJL21194 (May Also Be Branded ON ! )

The e-mail exchanges are reproduced below, but as you will see, the supplier name has been removed. I did ask, and was told that they would prefer not to be named, and so shall it be. Likewise, the reader's name is not reproduced.

I have read your article on fake transistors and thought you may be able to shed some light on a possible counterfeit transistor.

I have been working on a project using MJL21193 and MJL21194 transistors and have found what seems to be an anomaly in the packaging. The ON - MJL21193's have come directly from ON-Semi as samples and in all respects conform to the drawings on the data sheet. The Motorola MJL21194's were sourced through (a supplier) and there are some discrepancies between the package and the drawing.

The Motorola data sheet (old version, dated august 31 1995) and the ON data sheet (latest version from on, dated 9 June 2005) both show the same package information, both which match the authentic ON samples.

The suspect devices (see attached image) have steps in the plastic where the legs come out and the outer legs taper towards the center of the package rather that the center of each leg. Also, the heatsink surface is not flat but curved (convex). if I hold two together where they bolt on there is a 0.5 mm gap at the other end (0.25 mm each). The ON devices are dead flat (I cannot see light between two devices held together).

(The supplier) was adamant they get their stock from a large Australian supplier and that they had no concerns. Does this sound like cause for concern or is it normal that a manufacturer would use a different style package and is the flatness of the back of the package an issue? Note that the ON devices are lead-free so the metal finish may be different for that reason and is not necessarily another notable difference.

Response From ON Semiconductor Service Request #66471
ON Semiconductor Technical Information Center

Thank you for contacting ON Semiconductor

This device does not match our packaging and marking specifications. It is not ON Semi's or Motorola's device, because there is the year of production: 2000. ON Semi had take over the portfolio from Motorola in 1998. Also Motorola is not producing any semiconductors from this date, only whole electrical appliances.

Regards,
ON Semiconductor
Technical Information Center

I contacted the supplier and passed on the concerns as soon as I had confirmation that the devices were counterfeit. Later that same day I was able to confirm that all stores were instructed to check existing stock and return any fake devices to the warehouse.

Note the update above though - it seems that ON-Semi may be a little confused as to the actual date codes and the date that Motorola branding ceased.

The next batch of fakes are not marked as Sanken, but use the same type number as a Sanken transistor. While this does not make them (technically) counterfeits, they are still fraudulent. A transistor marked as a specific type should perform to a similar standard as the original, and this is very common with a lot of 'second sourced' components. This is where more than one manufacturer makes the same type number. In general, these second sourced devices can be expected to perform as well as the original.

That was definitely not the case with these devices. They are branded as 'IEC', but don't be surprised if this is not a known semiconductor supplier. There was nothing in the information I was given to indicate that the complement was also available as an 'IEC' device, but it is safe to assume that it will be in circulation.

Photos of the IEC 2SA1386 (Left) and for comparison, Sanken 2SC3855 (Right)

The original message I received on this topic came from Germany, but beware of these devices regardless of where you are ...

Hi Rod,
there are not many sites dealing with counterfeit transistors. great!

recently I ran into some transistors made by IEC which weren't that wonderful, at least they haven't been relabeled SANKEN.

The original SANKEN 2SA1386 is rated 130Watt with a SOA of 1,5A @ 60V continuous - The IEC survived a 1A 60V pulse of 1 sec.

When I tried it with 1,5A @60V it died after 0.4sec. Case temperature was only 20 (Celsius).

When I opened the case I saw that it has two dies parallel, each about 3 mm square, total area is 18 sqmm.

For comparison, The smaller SANKEN 2SC3855 (100W) has already a die of 5x5 mm = 25sqmm.

If you like you may put the pictures in your gallery, though these types are not used in your projects.

What we see here is a flat-pack version of the 'double-headed duds' described first for the MJ15003/4. This is the first time I have seen this done in a plastic package, and was obviously an attempt to make the transistors perform to some standard. Needless to say it failed. The smaller Sanken device (2SC3855) is not the complement to the 2SA1386 (that is the 2SC3519), but was included as a comparison - a smaller transistor with a bigger die area than one supposedly rated for higher power. Need we say more?

It's a very sad situation, but as I have mentioned elsewhere in this section, I consider it unwise to buy any Japanese transistors unless you are 100% certain of their pedigree. Whoever is doing the counterfeiting seems to have targeted the Japanese devices hard, and they won't stop now.

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