That is the right size die. But it looks like it may have had silicone, which is bad news in a plastic package. Who “made” it, and what were its markings (do you have one that’s not cracked open yet)? A lot of manufacturers have made them over the years, and they are generic parts.
These are from 2 ST batches - from 2 different fabs. The origin codes are different but the lead frames are the same and consistent with the data sheet. The China ones were from mouser, a few years ago. The Morocco ones came from a surplus house, in a mixed bag with several manufacturers - including some old TO-218.
I never pay more than a buck and a half, even from mouser.
For a 25 watt amplifier, a fake with a little bitty TIP41 size die in it would work. A bigger higher current die would sound better on low impedance speakers, of course.
I never pay more than a buck and a half, even from mouser.
For a 25 watt amplifier, a fake with a little bitty TIP41 size die in it would work. A bigger higher current die would sound better on low impedance speakers, of course.
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I never knew anyone would counterfeit TIP35... then again l, people counterfeit 2N3055s for some crazy reason. You'd think they'd focus on faking the more expensive transistors.
Have not seen a original semiconductor with that white stuff inside, that is used by cheap manufacture to ensure it won't come out of the tab with the heat and to ensure the tiny cables they use wont fuse with the first impulse they see, never the less have seen ones that fuse before you use them, my country is flooded with that kind of things, the ST good and original semiconductors (to-218) the tab has this rough finish and are never mirror finish, also the plastic is denser, and the cheap ones look like a molded fudge with rounded edges, sometimes they look like they were sanded and relabeled, they sometimes use factory rejects or pulls to sell them as new 😡 you may think it won't make any body rich but if you have unlimited access to this things and cheap hand labor you can do what ever you want.
The silicone sealing compound is usually a stiff fluid and has to "cure" or harden to the clear or white rubber-like coating you often see when you crack open generic parts. You may see specific industrial grades rated to 600F (315C) max. but they're not likely of a type suitable for fluid applicators. And yes, even genuine parts sometimes are assembled with silicone
Typical silicone sealants are only rated to 500F (260C) max. but there will still be slow decomposition when there is prolonged heat, even below 200C. So, you may well suspect you have fakes if there are early failures when run hot yet still within maximum die temperature limits.
On the other hand, I see that many DIY people here build and buy very high power amplifiers for home use but can't actually listen comfortably at even 10% of their capacity. So really, they may never get to test the semis to their ratings as they seldom deliver much more than their bias current requires. Maybe this explains why many folk are quite happy with their fake transistors too. Just don't tell them the facts about the log relationship between RMS power and perceived volume
Typical silicone sealants are only rated to 500F (260C) max. but there will still be slow decomposition when there is prolonged heat, even below 200C. So, you may well suspect you have fakes if there are early failures when run hot yet still within maximum die temperature limits.
On the other hand, I see that many DIY people here build and buy very high power amplifiers for home use but can't actually listen comfortably at even 10% of their capacity. So really, they may never get to test the semis to their ratings as they seldom deliver much more than their bias current requires. Maybe this explains why many folk are quite happy with their fake transistors too. Just don't tell them the facts about the log relationship between RMS power and perceived volume
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These transistors from Ali were dirt cheap, under 50 cents! But it seems they are good. I have original ST (from the wg_ski photo) which I use for higher power amps or amps with higher bias. I bought these Ali transistors just to see how good they are. For 50 cents, I am not disappointed. It's even possible that these Ali transistors are also genuine ST products, from one of their many factories around the world, intended for some specific countries (markets). I don't know, may be ST needs more production capacities and uses several Chinese factories.
Tom,
You are probably right but I think that what really matters is the die, leads and contact with the tab. wg_ski said that the die size is correct. In that respect tranies are worth 50 cents.
What I don’t get is why in the world would they put an expensive (relatively speaking) 150 watt die in a power transistor - and then label it as a device that normally sells for a buck? Unless the die was a reject. They are supposed to be destroyed, but they do find their way into circulation. I did find a fake MJ15024 once, that did have an original Motorola 2N5631 or something like it die inside. Along with a bunch of 2N3055 dies in the rest of them. The first one would have worked forever in the application. What clued me in to the fakes was the horrible matching between devices with the same date code. Then the lids popped right off....
I’m not sure. I’ve never seen the layout. When you crack open a real one with no silicone, the die crumbles. The part with the layout stays stuck to the molding - as it should - for proper moisture protection. So you get to see the die size but not the innards.
Your die looks like the run of the mill epi-base layout, similar to Motorola/ON, but obviously not theirs. This has squared off corners, ON’s are rounded. Looks
like something you would find in a second-source TO-3. I’ve seen lots of TO-3’s inside. It may work fine in a lot of applications, but I would suspect that the beta doesn't hold up too well at 25A. I use them in a small(ish) class G design where the low saturation voltage and high current capacity in a single package is important.
I just tested 12 pieces of TIP36C from the same Ali order using ATMEGA transistor tester. They look the same, except that they are marked "MAR" instead of "CHN". Beta was between 168 and 191. This is unusually high Beta. I remember that was also the case with TIP35C when I measured it. The die is definitely not TIP 35/36C die. Original TIP35/36C have much lower Beta. I do not have test gear to test power or frequency specs.
No, my memory failed me. TIP35C has Beta around 50-60. Huge difference in Beta between N and P transistor. P has much higher Beta. Is that normal?
TIP36 CHN Hfe 114
TIP36 MAR Hfe 115
TIP35 CHN Hfe 47
TIP36 MAR Hfe 95
TIP36, off brand (don’t recognize the symbol, but marked “Morocco” ) Hfe 130 might be made by ST
TIP34 (0ld ST, no origin code, but looks identical to above) Hfe 142
I have seen PNPs with higher Hfe at low current than NPNs. Including MJ2955’s (1980’s Motorola) that measure over 200. But at 10 amps they suck of course.
TIP36 MAR Hfe 115
TIP35 CHN Hfe 47
TIP36 MAR Hfe 95
TIP36, off brand (don’t recognize the symbol, but marked “Morocco” ) Hfe 130 might be made by ST
TIP34 (0ld ST, no origin code, but looks identical to above) Hfe 142
I have seen PNPs with higher Hfe at low current than NPNs. Including MJ2955’s (1980’s Motorola) that measure over 200. But at 10 amps they suck of course.
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I wont buy power transistors from Chinese or ebay vendors.
The chances they are fake are high.
Just pay a little more for them from a reputable dealer.
The chances they are fake are high.
Just pay a little more for them from a reputable dealer.