Received this reply in 2013 from ST FAE re inquiry about TIP35/6 process and SOA:
"I have just been informed that both devices had a change in the silicon line and process/technology where they are made—from epitaxial-based to planar—about 6-7 years ago.
The change didn’t affect the static values reported on the datasheet, but some typical values/curves might have changed.
I am waiting for a reply from someone else—in Europe—to let me know if any SOA curves are available.
Because the new parts have been in production for a few years now, and since SOA curves are not in the datasheet,
I doubt that there will be any to obtain; otherwise, they would probably be in the datasheet"
Never got answer to further inquiry about date or identification of change but apparently around 2006-7. Was told same dies used in ST versions of MJ802 and MJ4502
"I have just been informed that both devices had a change in the silicon line and process/technology where they are made—from epitaxial-based to planar—about 6-7 years ago.
The change didn’t affect the static values reported on the datasheet, but some typical values/curves might have changed.
I am waiting for a reply from someone else—in Europe—to let me know if any SOA curves are available.
Because the new parts have been in production for a few years now, and since SOA curves are not in the datasheet,
I doubt that there will be any to obtain; otherwise, they would probably be in the datasheet"
Never got answer to further inquiry about date or identification of change but apparently around 2006-7. Was told same dies used in ST versions of MJ802 and MJ4502
According to the ON data sheet, the second breakdown breakpoint in the SOA curve is at 30 volts. Always has been. Neither an epi-base nor a planar type will have any trouble doing that. It certainly don’t expect much more from the planar process. MJ802/4502 don’t have spectacularly high rated SOA either, despite being epi-base. Part of the reason why the SWTPC Tigers used to blow up. I’ve always preferred the 2N5631/6031 parts when SOA at 50 volts was a concern. Rated current isn’t as high but the beta holds up decently at 15A. I still have some old stock.
Probably for the same reason people put a small 200 V rated electrolytic cap into a larger can with a 400 V label on it. The manufacturing cost of that must be insane, so obviously they're doing this at significant production volume. Maybe they can make a fraction of a cent per component sold ... and sell millions of them.
Tom
I bought some quantity TIP35C and TIP36C from Ali and local shop. And all transistors are fake! They are has nice look and laser marking "ST" on top face. I not use transistor tester, because she for low current components, and testing power transistors is not good idea.
I use power supply 12 volts 20 amps and check collector-emitter saturation voltage. In all tested transistors saturation voltage is about 2-6 (!!!) volts, when base current is 2A. It is not same parameter of datasheet spec.
I broke transistors, and founded inside small crystal, size is 2x2mm.
It's too small for 25A collector current, see attached file!
I use power supply 12 volts 20 amps and check collector-emitter saturation voltage. In all tested transistors saturation voltage is about 2-6 (!!!) volts, when base current is 2A. It is not same parameter of datasheet spec.
I broke transistors, and founded inside small crystal, size is 2x2mm.
It's too small for 25A collector current, see attached file!
Attachments
Now that is one tiny little die. In the same package, and same markings as post #1, which had a 100+ watt die in it. Probably the same fakers, but they obviously don’t always use the same stuff.
If your having to ask if the transistor you bought is a fake then its highly likely you bought from the wrong source.
Forget China and ebay and use more reliable sources like RS, Mouser, Farnell etc.
Is saving a few pennies real worth the heartache and risk ?
The only time I buy from ebay is if the transistor is obsolete and I have no choice.
Forget China and ebay and use more reliable sources like RS, Mouser, Farnell etc.
Is saving a few pennies real worth the heartache and risk ?
The only time I buy from ebay is if the transistor is obsolete and I have no choice.
Someone else bought the same fake TIP35C and TIP36C that I had bought and took the attached picture. (Fakes in the middle.) Tiny die. But extremely good looking lead frame and marking. The lead frame might look so good because genuine lead frames are now made in the country that made/sold these fakes.
Attachments
It may be a “good looking” lead frame, but the outline on the back is supposed to look like post #5. Those notches are probably only there because it’s an ST-proprietary lead frame that not just anyone can go buy without someone asking questions. The plain-Jane one is wrong, as it is probably available to anyone.
In my opinion buying cheap active devices from other than authorised dealers could cost very expensive in the long run as they may fail and damage other parts of the circuit and even the expensive speakers in an amplifier setup. Take no chances for buying active components cheap and always buy from Authorised Dealer/Distributor.
Probably everyone else reading here would agree with the sentiment that we should always buy from authorised distributors. At least I try to. However, that is much easier to say than do with obsolete semis and the electronic component manufacturing and supply industry in the shape it is today.
Dealerships can only source generic TIPXXX parts now but you can't get fully specified parts that conform to any comprehensive datasheet unless the source is OEM and they must therefore comply with OEM datasheets. The TIP series were originally Texas Instruments general purpose products and the TIP35/6 pair came with copious release notes with fully detailed datasheets. However, that was long, like more than 40 years ago. Now all TIPXXX marked products are generic anyway, including those we call fakes, so who makes or is obliged to make their parts in full compliance with the OEM specs anyway?
It seems we need to guess whose parts are closest to the type/brand we either want, need or can tolerate in our application but without full data of the product and source, how can anyone determine what even the "trusted" dealers are selling us, especially those with bargain prices and bulk deals who are probably just priming the market by palming-off similar cheapo parts to those you find at online platform selling sites.
To be serious and use reliable sources, you should consider only current products from OEMs or bona fide second sources that must conform to published full specs. I have built enough projects with generic semis and disappointing results to know what a waste of time it is to expect similar results to those of the designer, when you substitute semis that are just a little too different to the specified type.
Dealerships can only source generic TIPXXX parts now but you can't get fully specified parts that conform to any comprehensive datasheet unless the source is OEM and they must therefore comply with OEM datasheets. The TIP series were originally Texas Instruments general purpose products and the TIP35/6 pair came with copious release notes with fully detailed datasheets. However, that was long, like more than 40 years ago. Now all TIPXXX marked products are generic anyway, including those we call fakes, so who makes or is obliged to make their parts in full compliance with the OEM specs anyway?
It seems we need to guess whose parts are closest to the type/brand we either want, need or can tolerate in our application but without full data of the product and source, how can anyone determine what even the "trusted" dealers are selling us, especially those with bargain prices and bulk deals who are probably just priming the market by palming-off similar cheapo parts to those you find at online platform selling sites.
To be serious and use reliable sources, you should consider only current products from OEMs or bona fide second sources that must conform to published full specs. I have built enough projects with generic semis and disappointing results to know what a waste of time it is to expect similar results to those of the designer, when you substitute semis that are just a little too different to the specified type.
Faking the expensive and difficult to make power transistors I get, but really ? Faking TIP35's ? They know no shame.
I wouldn't even contemplate buying in-production active devices from anywhere other than a proper supplier... it's just asking for trouble
I wouldn't even contemplate buying in-production active devices from anywhere other than a proper supplier... it's just asking for trouble
I don't know the figures but I would expect that the amateur/DIY market for very cheap power transistors in emerging economies is actually huge and still growing strongly because it covers much larger populations than previously, where only a relative few, rich hobbyists could afford to buy, let alone build up stocks of new and much needed power semis and general components.
Faking parts for the DIY market has fewer consequences because there is little professional testing in the hobbyist sector and thus little commercial pressure to provide genuine spec. parts if the 100W amplifier you thought you built can scarcely make 10W before blowing the cones out of your cheap but likely sensitive speakers.
On the other hand, no one likes to feed the sharks - the names you know well, who profit from distributing small quantities of components at substantial mark-ups and blow much of that on promotional advertising and uncompetitive practices like buying up the main opposition and having both businesses still appear to be duking it out in the same markets.
Faking parts for the DIY market has fewer consequences because there is little professional testing in the hobbyist sector and thus little commercial pressure to provide genuine spec. parts if the 100W amplifier you thought you built can scarcely make 10W before blowing the cones out of your cheap but likely sensitive speakers.
On the other hand, no one likes to feed the sharks - the names you know well, who profit from distributing small quantities of components at substantial mark-ups and blow much of that on promotional advertising and uncompetitive practices like buying up the main opposition and having both businesses still appear to be duking it out in the same markets.
You have a point.
I live in Argentina and we still have some Industry left and as you point , no Industry anywhere in the World has any use for fake parts: end products are series made and even 10% failures (meaning 90% of products might still be sellable) is catastrophic, both becuse bad parts make the whole product unusable/unsellable but also repairing it takes more time than actual assembly. A lose/lose situation.
When I started getting bad 2N3055 around 2006 even from previously trusted suppliers and even worse, even straight from Factory ST ones *barely* met datasheet specs (which is not enough in the stressful Musical Instrument market) I was FORCED to drop them (after 35 years of faithful service) and switch to TIP142/147 instead , apparently they re not worth faking.
Same thing happened with old workhorse 2N3773, I had to straight redesign using IRFP250 which are NOT faked, at least not from trusted suppliers (ARROW and AVNET, or US based Mouser or Digikey).
So if I buy, say, 100 or 500 transistors and find 3 or 4 bad, then the whole batch is rejected, and I´ll take NO BS from the seller.
I have experience enough, can make a test jig to blow them at will if fake, but show good ones do not, etc. BUT a hobbyist or even a Service guy buying 1 or 2 pairs for a single job (repair or home build): IF they work, good (generally a Home use receiver or amp is not THAT stressed), and if they don´t, seller usually claims "it´s your fault, you didn´t repair it well, some other part is causing the problem", etc. and poor Tech or advnced DIYer/Hobbyist is left full of doubts.
So shop keeps selling them for a long time.
So smaller, no own Industry Countries (say Honduras, Guatemala, Ecuador, Bolivia, etc) get MOSTLY the fake ones.
Also small local shops don´t buy straight from Factories or Area Distributors but from International resellers, many from Miami or Panama .... imagine parts quality, specially because there is NO accountability.
WHO will do the international detective work?
Yes, TIP142/147 can be fake now too, like TIP35/6. Probably *because* many in developing nations were moving *to* them to avoid fake 3055’s in the first place.
A lot of the DIY kits sold on AliExpress and others can’t put out ANYWHERE near advertised power anyway, because the voltages they run on are just too damn low. At +/-30 or 35 volts, fake 2SC3281’s WILL hold up on 8 ohm loads, at least for a while. Think about it. You could have used a 2N3055 in the first place, so a cheap generic epi-base die from one of the second source suppliers in the gray market would WORK. No one would be the wiser, especially a beginner hobbyist who doesn’t even know that his amp can’t put out the 200 watts they “said” it could (or why).
You *can* still get the old 2N3055 and 2N3773 “workhorses” from ON through their regular distributors, buy why? They are not any cheaper than MJ21194’s anymore. For any new manufacturing or customer-paid repairs, you may as well just use them and only stock one type. The *only* reason to buy 3773’s is finding NOS for a buck or two apiece - and then you have to TEST. Period. Is it a waste of time? Depends. For me, none of my audio work is anything I have to justify with a “business model” to satisfy creditors. What I have on hand when I pull the plug from regular employment is what I’ll have on hand, and the longer it lasts the better. I’ve bought a large stock of old types this way over 20 years, anticipating them drying up entirely. It *did* start 20 years ago and is happening much faster today. Even the current types from ON will not be around forever, and having the older workhorses and new types on hand will keep me up and running longer. And it’s not just the high power devices anymore - I did lifetime buys of ALL the stretch-TO92 and TO-126 types I use, many of the regular T0-92’s and a few select TO-220’s from Mouser and Digikey staring 4 years ago when EOL was announced on all the ON/Sanyo parts. To me it signaled the beginning of the end and prompted action that I’m extremely glad I took.. And a lot of my prior channels for getting older power types that I’ve used over the years has dried up too - much of it due to pandemic and places closing permanently. The stock-up over 20 years has been worth it - even the time/money many would consider “wasted”. What I did miss out on entirely were the Sanken LAPTs in the MT200 case. I just have a few pairs so I can’t be in the business of fixing expensive high end stereo equipment. Customers like that are willing to pay $600 to have their amp fixed somewhere else anyway.
A lot of the DIY kits sold on AliExpress and others can’t put out ANYWHERE near advertised power anyway, because the voltages they run on are just too damn low. At +/-30 or 35 volts, fake 2SC3281’s WILL hold up on 8 ohm loads, at least for a while. Think about it. You could have used a 2N3055 in the first place, so a cheap generic epi-base die from one of the second source suppliers in the gray market would WORK. No one would be the wiser, especially a beginner hobbyist who doesn’t even know that his amp can’t put out the 200 watts they “said” it could (or why).
You *can* still get the old 2N3055 and 2N3773 “workhorses” from ON through their regular distributors, buy why? They are not any cheaper than MJ21194’s anymore. For any new manufacturing or customer-paid repairs, you may as well just use them and only stock one type. The *only* reason to buy 3773’s is finding NOS for a buck or two apiece - and then you have to TEST. Period. Is it a waste of time? Depends. For me, none of my audio work is anything I have to justify with a “business model” to satisfy creditors. What I have on hand when I pull the plug from regular employment is what I’ll have on hand, and the longer it lasts the better. I’ve bought a large stock of old types this way over 20 years, anticipating them drying up entirely. It *did* start 20 years ago and is happening much faster today. Even the current types from ON will not be around forever, and having the older workhorses and new types on hand will keep me up and running longer. And it’s not just the high power devices anymore - I did lifetime buys of ALL the stretch-TO92 and TO-126 types I use, many of the regular T0-92’s and a few select TO-220’s from Mouser and Digikey staring 4 years ago when EOL was announced on all the ON/Sanyo parts. To me it signaled the beginning of the end and prompted action that I’m extremely glad I took.. And a lot of my prior channels for getting older power types that I’ve used over the years has dried up too - much of it due to pandemic and places closing permanently. The stock-up over 20 years has been worth it - even the time/money many would consider “wasted”. What I did miss out on entirely were the Sanken LAPTs in the MT200 case. I just have a few pairs so I can’t be in the business of fixing expensive high end stereo equipment. Customers like that are willing to pay $600 to have their amp fixed somewhere else anyway.
I have had a no of problems re fake transistors even the humble BD139/140
I repaired a Radford SPA 50 fitted with SPA boards tested ok and then blew up on switching on /off/ on
Fitted old stock devices result perfection
When listening to the radford I thought where have we come in the last 30 years truth is not far Having said that what was a £400 amplifier can now be matched at say £150
Trev
I repaired a Radford SPA 50 fitted with SPA boards tested ok and then blew up on switching on /off/ on
Fitted old stock devices result perfection
When listening to the radford I thought where have we come in the last 30 years truth is not far Having said that what was a £400 amplifier can now be matched at say £150
Trev