Well the die is full size - but it doesn’t necessarily follow that it’s equally rugged. Or have equivalent frequency response. It could, but that’s all. One of them had the molding compound de-laminate. Was there any white goop? If the encapsulation process isn’t solid, and there’s nothing in the interface to take the strain, eventually the die or bond wires will get damaged from thermal cycling. Just enough movement to fatigue things over time. Even the white goop is just a band aid. A proper passivation layer on the die directly bonded to the encapsulation is the proper way to build these. It looks like one of them came apart the way I’d expect a real Toshiba device to (on the right). Their assembly process is inconsistent, leading to hit or miss reliability. Even if the die itself is good, an assembly related reliability problem is almost as bad. Might not cause as much collateral damage in the amplifier though, as failing open is usually better for all the other parts than failing short.
Thanks Wg.. of course, I think These transistors C5200 and A1943 are not made by Toshiba anymore (I was said).. I was searching for SPTECH company and I see they produce semiconductors but I don't know if they are good. I will be posting here if I find any information. Thanks.
NOT sure why you saying that Toshiba C5200 and A1943 are NOT manufactured by Toshiba anymore. A simple search https://octopart.com/search?q=toshiba+C5200¤cy=USD&specs=0 will show that they are available literally everywhere, Digikey, Mouser, Newark etc.
Off the net, no ties:
Shenzhen SPTECH Micro-electronics Co., Ltd.
Address: No. 306, 3rd Floor, Bangtai Creative Park, Banxuegang Avenue Longgang District, Shenzen, China
Business Type: Manufacturer
'Shenzhen sptech is a high-tech enterprise specializing in the development, design, production and sales of power devices. Since its establishment in 2003, it has been continuously innovating in technology, introducing talents and equipment for 16 years to ensure that each product meets the highest standards in the industry. The independent brand "Shenzhen Quality Super sptech" is recognized by the customers of famous foreign enterprises with excellent quality and strong technical support. Their products meet RoHS EU and EU CE environmental protection standards. Shenzhen Quality Super sptech strives to become one of the most important power device manufacturers in the world'
Shenzhen SPTECH Micro-electronics Co., Ltd.
Address: No. 306, 3rd Floor, Bangtai Creative Park, Banxuegang Avenue Longgang District, Shenzen, China
Business Type: Manufacturer
'Shenzhen sptech is a high-tech enterprise specializing in the development, design, production and sales of power devices. Since its establishment in 2003, it has been continuously innovating in technology, introducing talents and equipment for 16 years to ensure that each product meets the highest standards in the industry. The independent brand "Shenzhen Quality Super sptech" is recognized by the customers of famous foreign enterprises with excellent quality and strong technical support. Their products meet RoHS EU and EU CE environmental protection standards. Shenzhen Quality Super sptech strives to become one of the most important power device manufacturers in the world'
http://zhichaowei.com/index.php/Category/product/id/28.html
Many TO-3 devices....MJ11028, BU508, TIP35 and more....!
Many TO-3 devices....MJ11028, BU508, TIP35 and more....!
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Thank you for this information about SPTECH.. since I have been using their transistors, I have had some problems to make three amplifiers work.. the causes are not by thermal runaway or high idle current, for these reason I want to feel sure about the products I am buying from the provider who sells these transistors to me. Thanks❤️
No ties, and I did not look very hard for ISO and other QC standards.
That is left to those who need to buy, there are links to Alibaba and Taobao stores of the seller.
That is left to those who need to buy, there are links to Alibaba and Taobao stores of the seller.
So no apparent thermal runaway… what symptoms did you see when the amplifiers failed? Just running along what appeared to be normally, not overheating, and suddenly poof? First time power up failure? Worked ok at 8 ohm but didn’t like 4? Oscillated itself to death?
Well, They work very well let us at less than half of volume but if I turned it up more than half, the transistors got very hot. Bias current is previously set safe, enough heatsink area and 6 ohms load.. +/-40V power supply.
An amp should just gradually get hotter the harder you run it - if it “hockey sticks” that indicates that something is misbehaving. The usual misbehaviors, however, happen before it even starts heating up. Breakdown happens pretty fast and is unforgiving. Class D often misbehaves at higher power while running fine at normal listening volume, but that’s a switching time issue. It may be thermally running away - which shouldn’t happen with a proper bias circuit and “enough” heat sink.
40V rails and 6 ohms should be absolutely no problem for C5200’s. Even C5198, C5242 or D1047 would take that all day, all night. Unless the problem really IS too small a heat sink what you’ve got are NFG.
40V rails and 6 ohms should be absolutely no problem for C5200’s. Even C5198, C5242 or D1047 would take that all day, all night. Unless the problem really IS too small a heat sink what you’ve got are NFG.
The heatsink is big enough for the output stage. I have to look for the circuit but I don't remember both Vbe multiplier transistor code 🤔 I used for Bias circuit.. I don't know if this might be the problem.
If the Vbe multiplier isn’t properly thermally tracking, you’d have a problem with any transistors. But it’s just not that hard to do. And if it works well with other output transistor types and not with these C5200’s the bias circuit isn’t the problem.
A photo with a ruler or measuring tape, to judge size, of the heat sink will be helpful, as 'enough' can be too small for a particularly high ambient temperature.
Texas will generally be hotter than Washington State or Illinois, for example.
Texas will generally be hotter than Washington State or Illinois, for example.
I am bringing this back, but....
Datasheet says that the transistors will have Japan on them if they were made in Japan, d’oh! the boxes show Japan on them , but your transistors DON'T!
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Hi, yes later i convinced that those are not original but good quality chinese copies. I have genuine 5200 with JAPAN marking on them.
Regards
Regards
You are right.. anyway I think it is for the first time I have this problem for this reason I wanted to know more about SPTECH transistors.
As Nano farias says: "There are good Quality chinese copies of high power transistors" I have worked with them and they work well but I am in Venezuela and here there are many fake transistors sold at the electronic part stores 🥲.
Well, nobody is going to “fake” SPTECH transistors. If someone makes a fake, it is either going to be marked Toshiba or ON. Because those cost the most, and therefore produce the highest profit. Better than ISC’s copy? Who knows. I’m not about to find out. Better than KEC? No field reports for those filtering in yet, but their drivers appear to be good. When Toshiba and Fairchild (On) quit making C5200’s we’ll find out.
The problem with “electronics parts stores” is that you never know where what they have comes from. If your country has draconian import restrictions and tariffs and prices are low, chances of getting a real one go way down. Real ones would be priced accordingly, if they can even GET them. In the states, those brick and mortar stores are all but dried up. In our business model if they bought them from Mouser for $3 a pop they would charge $9 (or more) over the counter. A $3 C5200 would have to be a fake - I doubt they could even sell ISC or SPTECH for that and make the required gross margins. Now, 69 cent 2N3904’s can be viable, because even if I needed one badly enough that it couldn’t wait 4 days I might be willing to spring for that. So would your typical college student trying to finish his project tonight.
The problem with “electronics parts stores” is that you never know where what they have comes from. If your country has draconian import restrictions and tariffs and prices are low, chances of getting a real one go way down. Real ones would be priced accordingly, if they can even GET them. In the states, those brick and mortar stores are all but dried up. In our business model if they bought them from Mouser for $3 a pop they would charge $9 (or more) over the counter. A $3 C5200 would have to be a fake - I doubt they could even sell ISC or SPTECH for that and make the required gross margins. Now, 69 cent 2N3904’s can be viable, because even if I needed one badly enough that it couldn’t wait 4 days I might be willing to spring for that. So would your typical college student trying to finish his project tonight.
Maybe you should edit your first post so other members can learn from your findings.