The die is 6mm*6mm which is what was suggested it should be.
Silicone just means a different manufacturing process.
They are CHEAP, but it doesn't mean they're bad ... Sometimes you know they're bad ... like if they had a 2mm * 2mm die! In this case though, the only way to know is to test them! They MAY just be acceptable.
Silicone just means a different manufacturing process.
They are CHEAP, but it doesn't mean they're bad ... Sometimes you know they're bad ... like if they had a 2mm * 2mm die! In this case though, the only way to know is to test them! They MAY just be acceptable.
Hi Dirk
There is no rule which says a company cannot manufacture a part which was introduced by someone else.
But I agree it is necessary to check whether the second-source manufacturer is making good products or not.
I think your suggestion earlier is a very good one - to check the second breakdown current ratings. This is a good way to see whether a transistor meets its specifications!
there have been many examples about counterfeits that it would be useful to have a second-breakdown test circuit for diy-audio-ers to try. I've sketched a circuit, but so far have not had a chance to explore it.
Perhaps there are other measurements which can be made as well. For example, small die might have a low capacitance. If you can measure Cbc and Cbe this might show (if it is too small) if the chip is possibly too small.
Also, measuring Vbe against Ic (the normal GUmmel plot) might also show if the die size is too small - if the Vbe has to be higher, for example, to give a certain collector current.
And measuring the fT should be possible, to see if a technical match to the spec. has been made.
Unfortunately measurements of Cjc and Vbe(Ic) won't necessarily confirm a problem, especially the Vbe. There is a high temperature sensitivity, and measurements on a "real" and "test" devices need to be made at the same temperature. And manufacturing process variations could change the results, but it may be that a gross difference could indicate a problem.
Measuring Cjc, second breakdown current, breakdown voltages, fT and current gain are tests which should be possible and could be revealing.
cheers
John
There is no rule which says a company cannot manufacture a part which was introduced by someone else.
But I agree it is necessary to check whether the second-source manufacturer is making good products or not.
I think your suggestion earlier is a very good one - to check the second breakdown current ratings. This is a good way to see whether a transistor meets its specifications!
there have been many examples about counterfeits that it would be useful to have a second-breakdown test circuit for diy-audio-ers to try. I've sketched a circuit, but so far have not had a chance to explore it.
Perhaps there are other measurements which can be made as well. For example, small die might have a low capacitance. If you can measure Cbc and Cbe this might show (if it is too small) if the chip is possibly too small.
Also, measuring Vbe against Ic (the normal GUmmel plot) might also show if the die size is too small - if the Vbe has to be higher, for example, to give a certain collector current.
And measuring the fT should be possible, to see if a technical match to the spec. has been made.
Unfortunately measurements of Cjc and Vbe(Ic) won't necessarily confirm a problem, especially the Vbe. There is a high temperature sensitivity, and measurements on a "real" and "test" devices need to be made at the same temperature. And manufacturing process variations could change the results, but it may be that a gross difference could indicate a problem.
Measuring Cjc, second breakdown current, breakdown voltages, fT and current gain are tests which should be possible and could be revealing.
cheers
John
At the same time, one has to be a little careful to determine whether the parameter you're checking REALLY matters for the application depending on whether the critical parameters are acceptable.
For example, most output stages do NOT require high gain, therefore the difference between a transistor with an hfe of 100 and another of 150 may not make much practical difference.
Unless you're very specifically designing with critical tolerances for a particular transistor, then an fT of 100MHz or 150MHz for example is hardly critical in an audio circuit other than ensuring it doesn't take off!
I always take these things in a very practical way ...
You buy some lemons from Spain, but instead you find they're from Morocco. Can you still make lemonade? Yup. Does it taste good? Yup. Does it need a little more sugar? Maybe. OK .. they're usable.
If you buy lemons from Spain and get shipped limes from Costa Rica, then can you make lemonade? Nope - but you can make limeade. Does it taste good? Yup. Will you accept limeade instead of lemonade? Yes - keep em. No - send them back and get a refund.
If you buy lemons from Spain and get shipped dried out lemons from California, can you make lemonade? Nope. Nothing you can do with these ... so send them back and get a refund.
The question is, are these transistors close enough to do the job being asked of them? If they are and it's too much hassle to send them back for a refund, or you might not get a refund, then why not use them! If they aren't good enough to use, then try to get a refund.
For example, most output stages do NOT require high gain, therefore the difference between a transistor with an hfe of 100 and another of 150 may not make much practical difference.
Unless you're very specifically designing with critical tolerances for a particular transistor, then an fT of 100MHz or 150MHz for example is hardly critical in an audio circuit other than ensuring it doesn't take off!
I always take these things in a very practical way ...
You buy some lemons from Spain, but instead you find they're from Morocco. Can you still make lemonade? Yup. Does it taste good? Yup. Does it need a little more sugar? Maybe. OK .. they're usable.
If you buy lemons from Spain and get shipped limes from Costa Rica, then can you make lemonade? Nope - but you can make limeade. Does it taste good? Yup. Will you accept limeade instead of lemonade? Yes - keep em. No - send them back and get a refund.
If you buy lemons from Spain and get shipped dried out lemons from California, can you make lemonade? Nope. Nothing you can do with these ... so send them back and get a refund.
The question is, are these transistors close enough to do the job being asked of them? If they are and it's too much hassle to send them back for a refund, or you might not get a refund, then why not use them! If they aren't good enough to use, then try to get a refund.
Hi Dirk,
I'm a semiconductor device professional.
May I can help you and the others at this case.
First, iscsemi is a well known semicondutcor manufacturer, located in Wuxi China close to the German Infineon plant, specialized on Discrete Power Devices.
The devices in question 2SC2922 and 2SA1216 in the specified device package MT-200 are first designed and manufactured by Sanken Electric in Japan and are on the official product list of iscsemi.
If a semiconductor manufacturer designs a new device it has to be registered with all product parameters and specification as well as the package design at the international semiconductor standardization organization JEDEC.
JEDEC plublishes the registered device on their official publication.
After a certain protection time such devices can be manufactured by other companies to. But - by using the same device designation, the device must be conform with the origin product parameters and specification including the package design.
Iscsemi is registred as origin manufaturer of the mentioned devices at JEDEC.
For sure there are some manufacturing process deviations resulting in slightly different package surface or smooth corners often seen at the metal heatsink. As long as such small deviations don't impact the device parameters and specs, there isn't any reason to be doubtful of the device quality.
But I must mention, due to different semiconductor manufacturing prozesses, which can deviate from the origin process used at Sanken, such device used at Audio application can result in slightly different sound colours, not necessearily important but detectable.
You have also mentioned the 2SC2922 surface has been reworked with sandpaper. The attached photograph support this impression.
Sometimes in production it appears that a wrong designation has been printed, or they aren't in the range of the subcode specs, which require rework.
The manufacturer of these devices has been using laser marking for designation printing which engrave the surface and can't be simply removed with solvents as in the past with ink-printing. Thus correcting the designation require manual rework with sandpaper, a standard procedure with some Chinese manufacturer, but rarerly seen at Japanese companies.
Recommended actions:
1. To check if your devices corresponds to the origin product specifiaction and if you don't have the ability to measure the important product parameters, you should send some examples to an institute of an university having an electronic faculty, which can easy check the parameters.
2. If you board such devices from an official German distributor, who sold the devices under the origin of Sanken, he is obliged to retake them, due to incorrect sales conditions.
3. General purchasing recommendations:
3.1 Buy only from serious sources as from official distributors
3.2 If you buy over ebay, I would not recommend any purchase from private institutions.
3.3 If a device has been aquired from an official distributor under a specific product and manufacturer designation (Sanken), the delivered devices must correspond to the origin device. In case the original device isn't on stock, the supplier must ask you prior to shipment, if an equivalent type can be send.
The German disti Reichelt offer such devices in their "Japan Transitor" list. In this case it "must" be Japanes origin. The product designation only (2SC2922 f.i.), first registred from Sanken, isn't automatically a Japanese origin product, but if mentioned Japanese product, Japanese must be in.
Cheers
Gerd
I'm a semiconductor device professional.
May I can help you and the others at this case.
First, iscsemi is a well known semicondutcor manufacturer, located in Wuxi China close to the German Infineon plant, specialized on Discrete Power Devices.
The devices in question 2SC2922 and 2SA1216 in the specified device package MT-200 are first designed and manufactured by Sanken Electric in Japan and are on the official product list of iscsemi.
If a semiconductor manufacturer designs a new device it has to be registered with all product parameters and specification as well as the package design at the international semiconductor standardization organization JEDEC.
JEDEC plublishes the registered device on their official publication.
After a certain protection time such devices can be manufactured by other companies to. But - by using the same device designation, the device must be conform with the origin product parameters and specification including the package design.
Iscsemi is registred as origin manufaturer of the mentioned devices at JEDEC.
For sure there are some manufacturing process deviations resulting in slightly different package surface or smooth corners often seen at the metal heatsink. As long as such small deviations don't impact the device parameters and specs, there isn't any reason to be doubtful of the device quality.
But I must mention, due to different semiconductor manufacturing prozesses, which can deviate from the origin process used at Sanken, such device used at Audio application can result in slightly different sound colours, not necessearily important but detectable.
You have also mentioned the 2SC2922 surface has been reworked with sandpaper. The attached photograph support this impression.
Sometimes in production it appears that a wrong designation has been printed, or they aren't in the range of the subcode specs, which require rework.
The manufacturer of these devices has been using laser marking for designation printing which engrave the surface and can't be simply removed with solvents as in the past with ink-printing. Thus correcting the designation require manual rework with sandpaper, a standard procedure with some Chinese manufacturer, but rarerly seen at Japanese companies.
Recommended actions:
1. To check if your devices corresponds to the origin product specifiaction and if you don't have the ability to measure the important product parameters, you should send some examples to an institute of an university having an electronic faculty, which can easy check the parameters.
2. If you board such devices from an official German distributor, who sold the devices under the origin of Sanken, he is obliged to retake them, due to incorrect sales conditions.
3. General purchasing recommendations:
3.1 Buy only from serious sources as from official distributors
3.2 If you buy over ebay, I would not recommend any purchase from private institutions.
3.3 If a device has been aquired from an official distributor under a specific product and manufacturer designation (Sanken), the delivered devices must correspond to the origin device. In case the original device isn't on stock, the supplier must ask you prior to shipment, if an equivalent type can be send.
The German disti Reichelt offer such devices in their "Japan Transitor" list. In this case it "must" be Japanes origin. The product designation only (2SC2922 f.i.), first registred from Sanken, isn't automatically a Japanese origin product, but if mentioned Japanese product, Japanese must be in.
Cheers
Gerd
Since these are with no doubt the fake inferior parts that are hurting us so much, I wonder if we have some fake seller friends here trying to avoid the embarrasement...
Genuine MT-200 parts must look like this:
And I also have plenty of experience with these parts...
All these are fakes, fortunately I managed to return the fake lot and get a refund:
All the transistors manufactured with the withe-goo process are unreliable fakes. Genuine parts sourced from a quality process have either a thin transparent resin coating over the die, or no coating at all.
This page contains plenty of fake vs genuine pictures demonstrating the previous fact:
http://transfal.tripod.com/indexold.html
Genuine MT-200 parts must look like this:
And I also have plenty of experience with these parts...
All these are fakes, fortunately I managed to return the fake lot and get a refund:
All the transistors manufactured with the withe-goo process are unreliable fakes. Genuine parts sourced from a quality process have either a thin transparent resin coating over the die, or no coating at all.
This page contains plenty of fake vs genuine pictures demonstrating the previous fact:
http://transfal.tripod.com/indexold.html
A posible reason for relabeling- operator boredom. When I used to work in a plastics factory, one of the parts made there was the front panel of set top boxes. The machine for printing the labels got mis-aligned over time. The people running the machine were low paid, bored, and often on drugs or just plain stupid. Hundreds of incorectly printed front panels could be packed during the night shift, leaving someone with the job of removing the ink from the panels to be reprinted. We used solvents and rubbed them with a cloth. But if asthetics werent important the writing could have been removed much quicker with sand paper!
Hi Gerd,
first, thx for the very good informations.
And its right that the label is printed with laser.
I then can hope thats the 2SC2922 is from ISC and the transistors hold the spec´s from the Datasheet (that i can´t download on homepage from ISC, there is no 2SC2922 on it
And when the sound is a little bit different to Sanken, with that i can living.
important for me is that this 2SC2922 are no fake or Counterfeit and i can use it in a amp and the Amp don´t burn out after one hour hard sound of AC/DC))
greetings from germany
Dirk
first, thx for the very good informations.
And its right that the label is printed with laser.
I then can hope thats the 2SC2922 is from ISC and the transistors hold the spec´s from the Datasheet (that i can´t download on homepage from ISC, there is no 2SC2922 on it
And when the sound is a little bit different to Sanken, with that i can living.
important for me is that this 2SC2922 are no fake or Counterfeit and i can use it in a amp and the Amp don´t burn out after one hour hard sound of AC/DC
))greetings from germany
Dirk
Hi Eva,
you have many fakes of sanken. OK, fake of sanken Transis, i can understand. Because sanken are good and expensive. But ISC isn't so known as sanken, why fake this.
but when i look on the side from your link, in the future I must have afraidly to buy a Transistor, because there counterfeit all what it give on the market.
Nice photo of the sanken transis, pls send me 10 of 2Sc2922 and 10 of 2SA1216 !)))
Dirk
you have many fakes of sanken. OK, fake of sanken Transis, i can understand. Because sanken are good and expensive. But ISC isn't so known as sanken, why fake this.
but when i look on the side from your link, in the future I must have afraidly to buy a Transistor, because there counterfeit all what it give on the market.
Nice photo of the sanken transis, pls send me 10 of 2Sc2922 and 10 of 2SA1216 !
)))Dirk
They don't have a datasheet for a good reason... lol...
I think they are packing a "generic" power die in a fake MT200... They use to produce several different transistor models with the same generic die. Fakes of one model are frequently relabeled to supply demand of another model. They don't care about the performance differences between models since no one matches the specs of the genuine devices anyway. Forget about Sanken performance (high and linear hFE, 50Mhz Ft) which is exclusive of Sanken LAPT process, what you have is MJ15015/MJ15016 1970's performance (then, why not using these other devices?)
I tried a couple of the Sanken fakes shown in the last picture in one of my amplifier prototypes and it was not even stable. It oscillated due to the poor bandwidth of the fakes while it was unconditionally stable with genuine parts.
Why manufacturing 2SC2922 and 2SA1216 under another name? Because Sanken parts are of great quality and widely used, and there will be always people willing to buy the same part number with another brand for less money and expecting them to be as good the originals... It's like buying a Renault with a BMW sticker and believing you have a BMW.
If you ask them for a lot of 2SC3264 and 2SA1295, or any other MT200, they will sand the cases again and sell you the same parts relabeled to read what you asked for...
I think they are packing a "generic" power die in a fake MT200... They use to produce several different transistor models with the same generic die. Fakes of one model are frequently relabeled to supply demand of another model. They don't care about the performance differences between models since no one matches the specs of the genuine devices anyway. Forget about Sanken performance (high and linear hFE, 50Mhz Ft) which is exclusive of Sanken LAPT process, what you have is MJ15015/MJ15016 1970's performance (then, why not using these other devices?)
I tried a couple of the Sanken fakes shown in the last picture in one of my amplifier prototypes and it was not even stable. It oscillated due to the poor bandwidth of the fakes while it was unconditionally stable with genuine parts.
Why manufacturing 2SC2922 and 2SA1216 under another name? Because Sanken parts are of great quality and widely used, and there will be always people willing to buy the same part number with another brand for less money and expecting them to be as good the originals... It's like buying a Renault with a BMW sticker and believing you have a BMW.
If you ask them for a lot of 2SC3264 and 2SA1295, or any other MT200, they will sand the cases again and sell you the same parts relabeled to read what you asked for...
Eva said:
Since I'm the only one here really suggesting that these could be quite usable transistors, this is clearly pointed at me.
Well, Eva, I am not in the components sales business. The smallest "component" you can buy from me right now is an Digital RA90 disk drive for about $50 or a PDP-11/83 CPU card for about the same because ancient computer spares is part of my computer consulting business.
Just so we're clear here. I *am* an electronics engineer and have been since the 1960s but got into computers as my business in 1976. Whilst I have considered selling components for hobbyists, I have no interest in getting into the sales of Japanese type (2S etc) semiconductors for the very reason that you are all experiencing with either low quality components or outright counterfeit useless components. What I would want to source are name brands of a standard range of N. American and European transistors. There's enough fakery in these but I would only buy production types.
So please be careful in tossing around comments like you did.
Thanks!
oh, ISCSemi produce the 2SC2922. But the homepage of ISC has many bugs. One is that there has a big hole in the Transistorlist in the html table between page 3 to 4. Lost one complete page with many transistor. And the other that you cant donwload datasheets for the 2SA. when you klick on pdf icon you come back to the same page. On all pdf icons by 2SA transis. For a big company is that a bad page *lol*
In the pdf download file, the 2SC2922 is in the list with following data:
ISC 2SC2922
Pc(W) : 200
Ic : 17
Vceo : 180
Vcbo : 180
Vebo : 5
Hfe by Vce(V)=4 Ic(A)=8 : 50-
Vce(sat) by Ic(A)=8 Ib(A)=0.8 max : 2
Ft(Mhz) : 50
Sanken 2SC2922
has the same data, when i look right, only the Hfe begins smaller by 30- and then higher.
I have the same problem, In the last day in known now that 4 company´s produce 2SA1216 and 2SC2922.
Frist :
Sanken : http://www.sanken-ele.co.jp/
and then :
ISCSemi : http://www.iscsemi.cn/
Mospec : http://www.mospec.com.tw/
WingShing : http://www.wingshing.com/en/
All produce this transistors in mt-200, only mospec produce it in top3.
but when you google about the other Company´s you dont find any infos about this and 2S transistors.
Has here any other infos about this companys and use one of the transistor from one of these companys ?
i hope that my 2SC are ok and hold what the datasheet says.
In future i will only buy original Sanken by a official distributors here in germany.
Knows everyone a official distributors for sanken in germany ?
Is Schuro a official distributors for sanken in germany ?
http://www.schuro.de/preisl-jap-trans.htm
Dirk
I stumble at MOSPEC parts from time to time and quality seems reasonable, at least I think that their manufacturing process is better than the white silicone stuff... If they weren't able to clone the MT-200, the TO-3P seems like the right choice because the heat spreader is thicker and more effective than the flat and thin one used in the fake MT-200.
The transistors from KEC that I have seen also seemed to be of good quality (at least their old TIP35C and TIP36C were very rugged) http://www.keccorp.com/
Korean companies seem to be far more honest than Chinese ones.
Please accept my apologies, sbrook. Fakes get me angry because I like to use the full capabilities of transistors and ICs. For example, once I built a quick amplifier prototype with +/-80V rails and two pairs of genuine 2SC3264/2SA1295 and it was able to drive 4 ohms without failing (was it the heavy copper heat spreader?). I can't agree with anybody stating that fake parts are useable, as there are plenty of genuine lower power parts capable of doing the same job, even for *less* money. By buying and accepting fakes you are giving profit to the wrong people and encouraging them to produce more and more fakes. We must stop this process by proving to component dealers that they can't successfully sell us anything but high quality stuff (so that they stop buying junk from obscure sources).
The transistors from KEC that I have seen also seemed to be of good quality (at least their old TIP35C and TIP36C were very rugged) http://www.keccorp.com/
Korean companies seem to be far more honest than Chinese ones.
Please accept my apologies, sbrook. Fakes get me angry because I like to use the full capabilities of transistors and ICs. For example, once I built a quick amplifier prototype with +/-80V rails and two pairs of genuine 2SC3264/2SA1295 and it was able to drive 4 ohms without failing (was it the heavy copper heat spreader?). I can't agree with anybody stating that fake parts are useable, as there are plenty of genuine lower power parts capable of doing the same job, even for *less* money. By buying and accepting fakes you are giving profit to the wrong people and encouraging them to produce more and more fakes. We must stop this process by proving to component dealers that they can't successfully sell us anything but high quality stuff (so that they stop buying junk from obscure sources).
I jsut want to say that I replaced suspected fake Toshiba 2sc5200 for ISC 5200 and complimentary, and the sound change was an improvement in my opinion. Also I have driven the amp to about its dynamic max for 12 hours over newyears...
Sadly many of us have to choose between the devils we know becasue of lacking distrubution setup of the main manufactures....
For the transistor I mentioned, I need to buy 100 at more than digikey single cost from the local authorised distributor...
Sadly many of us have to choose between the devils we know becasue of lacking distrubution setup of the main manufactures....
For the transistor I mentioned, I need to buy 100 at more than digikey single cost from the local authorised distributor...
Hi Dirk, Eva,
I agree, we should never accept fake parts and should without any excuse legally attack their sellers.
On the other hand, the devices in question are general purpose power devices. The audio market compared to general purpose application is very small. The Sanken have got a good reputation in the audio market, but still the main volume is produced for general purpose for which the audio quality - which by the way can not be measured - isn't relevant.
As I have mentioned in my previous post, any manufacturer who has been registered and accepted at JEDEC as manufacturer of such devices can produce it as long they are in line with the registered specifications.
In addition for audio power application the hfe variation spec is important. If the variation is much lager than from the original device, matching transitor pairs is unavoidable.
My personal experience with devices from second source manufacturer show larger hfe variation, which make them finally more expensive if you need to buy more and select acceptable pairs.
If people intent to use devices produced from other suppliers than from Sanken as it is here the case, must keep in mind that there can be some sound deviations as previously mentioned.
As long as the manufacturer don't use the Sanken trade name it is a normal and legal proceeding.
For audio application I would anyway recommend to use only the original proposed device type for which the circuit has been developed.
Dirk,
I have also checked the iscsemi product list and couldn't find the page with the 2SC2922. But I have send them an e-mail with my request for such a device. Let's wait for their answer.
At this moment I don't know any official Sanken Distributor in Germany, but I will find out over the Sanken sales department.
Schuro isn't an official distributor only a dealer. If Schuro propose original Sanken devices, according to German roules, Schuro will be made responsible for the origin of their products - again if "Japanese product" has been mentioned, Japanese must be in - in your case Sanken.
Cheers
Gerd
I agree, we should never accept fake parts and should without any excuse legally attack their sellers.
On the other hand, the devices in question are general purpose power devices. The audio market compared to general purpose application is very small. The Sanken have got a good reputation in the audio market, but still the main volume is produced for general purpose for which the audio quality - which by the way can not be measured - isn't relevant.
As I have mentioned in my previous post, any manufacturer who has been registered and accepted at JEDEC as manufacturer of such devices can produce it as long they are in line with the registered specifications.
In addition for audio power application the hfe variation spec is important. If the variation is much lager than from the original device, matching transitor pairs is unavoidable.
My personal experience with devices from second source manufacturer show larger hfe variation, which make them finally more expensive if you need to buy more and select acceptable pairs.
If people intent to use devices produced from other suppliers than from Sanken as it is here the case, must keep in mind that there can be some sound deviations as previously mentioned.
As long as the manufacturer don't use the Sanken trade name it is a normal and legal proceeding.
For audio application I would anyway recommend to use only the original proposed device type for which the circuit has been developed.
Dirk,
I have also checked the iscsemi product list and couldn't find the page with the 2SC2922. But I have send them an e-mail with my request for such a device. Let's wait for their answer.
At this moment I don't know any official Sanken Distributor in Germany, but I will find out over the Sanken sales department.
Schuro isn't an official distributor only a dealer. If Schuro propose original Sanken devices, according to German roules, Schuro will be made responsible for the origin of their products - again if "Japanese product" has been mentioned, Japanese must be in - in your case Sanken.
Cheers
Gerd
you find the 2SC2922 on a list, that you can donwload. Look on top in menu "Company->Download Center" and the download Datasheet.pdf In this list you find the lost 2SC transis.
thats the problem. Nobody know a official Distributor for Sanken. All know only normal dealers.
I wonder once what ISCSemi says. i dont get a answer after my second question and send them the picture of the dirty rag.
When the 2SC2922 is a original ISCSemi that hold the spec, thats ok for me (the ISC cost a half of Sanken) but when its not ok, its a fake of ISC or other and my Amps burn out, then i become a big neck.
But at begin next month i have birthday and then i will buy original Sanken !!!
But you have right. ISC are Chinese and not Japan, how it is in the list at reichelt!
Dirk
Eva said:
Thank you ... accepted.
[QUOTE[Fakes get me angry because I like to use the full capabilities of transistors and ICs. For example, once I built a quick amplifier prototype with +/-80V rails and two pairs of genuine 2SC3264/2SA1295 and it was able to drive 4 ohms without failing (was it the heavy copper heat spreader?). I can't agree with anybody stating that fake parts are useable, as there are plenty of genuine lower power parts capable of doing the same job, even for *less* money. By buying and accepting fakes you are giving profit to the wrong people and encouraging them to produce more and more fakes. We must stop this process by proving to component dealers that they can't successfully sell us anything but high quality stuff (so that they stop buying junk from obscure sources). [/B][/QUOTE]
I can understand what you're saying, but at the same time there are copies (made by other companies but cheaper) and there are fakes (made by rogue outfits and are not in any way what is being sold.
In most industries, copies of things are made "under license" because of copyright type issues. In the semiconductor industry, unless a part uses unique technical patented construction methods, licensing is often not needed, or they're made in places where licensing is not required. Many copies are made with subtly different parameters.
Fakes or counterfeits are a different matter altogether. They are intended to sell what appears to be a brand name product but is nothing of the sort ... not even close.
ISC do copies and not necessarily particularly good quality copies at that. If you buy a "copy" and know you're getting a copy (as opposed to a transistor made by the original manufacturer like in this case, Sanken) then you should be accepting the fact that you're not getting the top quality, but you should be getting something close.
It's kind of like the generic drug industry. There are companies that make patented drugs "under license" and there are those who make copies of out of patent protection drugs we call generics, both of which are copies.
I take a medication that is quite inexpensive as a generic, but about 1/3 to 1/2 the cost of the original brand name manufacturer, and the generic works, but there are differences. The generic has a different release rate to the brand name and different release rate between batches. It works but the overall effectiveness of the medication is not as good as the brand name. BUT I can't afford the brand name because I don't have a drug plan, so I use the generics which provide me with adequate relief from my condition.
As was mentioned by someone else, if someone wanted to do fakes of these transistors, it would make no sense to do a fake of an ISC, nor would it make sense to put in 36 sq mm dies, when standard practice is to put in a small signal transistor die and label it with the brand name (Sanken).
So, my point is that these are probably copies and not fakes. It may be a reasonable, or it may be a poor copy - testing is the only way to know.
The question is what did the OP buy?
Did he think he was getting Sanken Japanese transistors? If so, then he was ripped off and should absolutely return them.
Did he know he was getting ISC transistors? If so, he probably got what he paid for, and the only way to make sure is to thouroughly test them. If they test out to a reasonable tolerance of the ISC part specs, then he's got what he ordered - maybe not what he was hoping for - but probably didn't realize the ISC copy was not going to be as good as the Sanken original. If on the other hand the test of these shows them to be outside tolerance of the specs of the device, then he should return them.
Of course, there are good copies and bad copies. For example, Fairchild is producing KSC5200 and KSA1943 with similar quality to Toshiba original parts.
The point is that MT-200 transistors by definition have a big copper thermal pad soldered on top of the back plate (see pictures) and any good copy must include this thermal pad because it's required to achieve rated power handling and SOA. The copies made by ISC don't include it, instead, the bare die is attached to a thin bottom plate resulting in TO-220-like power handling.
The point is that MT-200 transistors by definition have a big copper thermal pad soldered on top of the back plate (see pictures) and any good copy must include this thermal pad because it's required to achieve rated power handling and SOA. The copies made by ISC don't include it, instead, the bare die is attached to a thin bottom plate resulting in TO-220-like power handling.
