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Old 11th November 2006, 08:53 PM   #31
anatech is offline anatech  Canada
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Hi Mike,
It's just human nature. Everyone wants a deal, even at the expense of someone else.

Is that greed? I think so.

-Chris
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Old 13th November 2006, 02:27 AM   #32
Mimas is offline Mimas  Russian Federation
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Default Genuine or fake 2sk170

I'm concerned about my 2SK170's...

Idss testing(at 9 volt) for left transistors:
6,22 (mA)
6,26
6,92
9,95

And those on the right:
6,65
6,8
6,82
6,85
6,93
7
7,13
7,18
7,49
7,5
7,56
7,63
7,64
7,7
7,74
7,84
7,93
8,13
8,13
8,81
9,15
9,34
9,4
9,45
9,53
9,63
10,25
10,25
10,43
10,73

Can someone confirm on which ones are genuine?

Click the image to open in full size.
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Old 17th November 2006, 06:16 PM   #33
Onra is offline Onra  Germany
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Default BL-range of datasheet

Hi,
the Toshiba datasheet says: IDss between 2.6 and 20mA.
Classification:
GR 2.6 to 6.5mA
BL 6.0 to 12mA and
Y 10 to 20mA
According to the datasheet they are well within the "BL" range.

regards
Onra
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Old 29th December 2006, 03:12 PM   #34
PB2 is offline PB2  United States
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Quote:
Originally posted by anatech
Hi Pete,
Good idea for incoming inspection. The best defence is to only buy from a traceable supplier. If you do that the chances of getting caught with fakes are greatly reduced. That was the purpose of this thread. The parts I've posted come from a known supply chain. The On Semi parts were On Semi samples, directly from On Semi. This was the only way to guarantie the measurements and pictures. This is in hopes to allow our members from other countries with longer supply chains a chance at identifing fake parts.

The only thing I can say too is that if the price is too low, there is something wrong. Either stolen, rejected or outright copies of parts. Don't feed that market.

-Chris

This all makes sense Chris, I worked in defense electronics so I'm familiar with traceability. However, there is a secondary market for excess inventory and sometimes it's not possible to know the source. One can look for factory sealed boxes, and authorized dealer markings as a start.

I've got some Sanken 2SA1186 and 2SC2837s here and I want to crack a few open for a first look. Anyone have the technique down? Thinking vice, chisel, dremel tool?

Thanks,
Pete B.
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Old 29th December 2006, 06:49 PM   #35
anatech is offline anatech  Canada
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Hi Pete,
I'd be thinking vise. Controllable pressure without excessive penetration. So much for brute force and ignorance - as effective as it can be. Never mind expedient.

How many do you have there? Before playing silly bug-ger, we can measure capacitance and hFE. You could fire on or two of each up here if there is no one closer to you.

Then there is that satisfying "crack!" as the case opens to reveal the secrets within. Hard to beat that.

-Chris
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Old 29th December 2006, 08:17 PM   #36
PB2 is offline PB2  United States
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Quote:
Originally posted by anatech
Hi Pete,
I'd be thinking vise. Controllable pressure without excessive penetration. So much for brute force and ignorance - as effective as it can be. Never mind expedient.

How many do you have there? Before playing silly bug-ger, we can measure capacitance and hFE. You could fire on or two of each up here if there is no one closer to you.

Then there is that satisfying "crack!" as the case opens to reveal the secrets within. Hard to beat that.

-Chris

They're from a friend who's in the business of excess inventory.
I won't mention the name of the company, so that I don't get in
trouble with the other mods. I don't know if we're allowed to talk
about this friend. He has other types, and large quantities, this
particular lot is all Sanken. If the mods allow it I'll tell you
whatever you want. I am involved with machine based vision
there for quality control, but not for these particular parts. I do
consulting work there.

I'm not sure of the exact numbers I can check, over 1000 of
each though as a minimum. I was going to crack a few open and
see what's there. They look good so far based on Rod Elliot's
site: http://sound.westhost.com/fake/counterfeit-p2.htm#sank1
Thick lettering.
Centered Lot codes.
Many are in factory sealed boxes.

I would probably do an SOA test as the first electrical test,
but probably won't need to if we pop a few open.

These are graded for hfe, and these are the best Y grade, 90 min
to 180 hfe.
I don't expect there to be a lot of interest in these, and so I'm
just doing this out of curiosity.
These are impressive parts, is Sanken still making them?

Pete B.
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Old 30th December 2006, 12:48 AM   #37
anatech is offline anatech  Canada
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Hi Pete,
They are compliments rated at 150V, 10A, 100W and a target hFE of 60 for the series. Yours are pretty high in that regard. fT is rated at 70 MHz. So they are very useable and may work well in a Symasym.

Does that agree with what you know?

-Chris
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Old 30th December 2006, 03:28 AM   #38
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Default grey market rransistors

iirc the grey market for semiconductors has been active for a long time. back in 1982 i read an article about chinese companies buying reject lots of semiconductors from the real manufacturers (like hitachi, toshiba, sanken, sanyo, sony, etc...) and building knock-offs of consumer electronics (like "pionex" copies of pioneer equipment). that part of it is nothing new, but this practice of using multiple low performance dies to "simulate" a high performance transistor is something new. another potential source of knock-off semis is the distribution chain itself.... what does a distributor do if a certain date code or lot number of a particular component gets reported to have an unusually high failure rate, or out of spec lots? i would hope the distributor would return them to the manufacturer, but this may not always be the case. the part is already out there, and is for all intents and purposes, an original part, except it's from a bad lot or date code, and all the counterfeiter has to do is buy them cheap and resell them to other distributors that don't know it's a bad lot. when i get an OOB (out-of-box) failure on several of the same component with the same date code, i report it to the distributor, and mot reputable distributors will replace OOB failed components, and even sort replacements so you don't end up with a bunch of components from that same date code that you reported to them. usually distributors will report bad date codes back to the manufacturer, who will tell the distributor to return the entire remaining stock of that date code for credit. usually the manufacturer remelts the returned devices.

btw, wouldn't b-c capacitance (Ccb) be more directly related to die area than b-e capacitance (Cbe)?
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Old 30th December 2006, 02:29 PM   #39
PB2 is offline PB2  United States
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Quote:
Originally posted by anatech
Hi Pete,
They are compliments rated at 150V, 10A, 100W and a target hFE of 60 for the series. Yours are pretty high in that regard. fT is rated at 70 MHz. So they are very useable and may work well in a Symasym.

Does that agree with what you know?

-Chris

Hi Chris,
This is right from the Sanken data sheet:
2SC2837
NPN 150V 10A 100W 3P/TO3, hfe 50 min, ft 70 MHz, Cob 60pF
hFE rank O(50to100) P(70 to 140) Y(90 to 180)

Here's the data sheet in .pdf:
http://www.sanken-ele.co.jp/en/prod/...f/2sc2837e.pdf

Here's an index of Sanken data sheets:
http://www.sanken-ele.co.jp/en/prod/..._u/ptr_01e.htm

They have good SOA characteristics so they'd be good for many designs up to probably 50 W. I'd probably use pairs for higher power designs.

Pete B.
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Old 30th December 2006, 02:38 PM   #40
PB2 is offline PB2  United States
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Default Re: grey market rransistors

Quote:
Originally posted by unclejed613
iirc the grey market for semiconductors has been active for a long time. back in 1982 i read an article about chinese companies buying reject lots of semiconductors from the real manufacturers (like hitachi, toshiba, sanken, sanyo, sony, etc...) and building knock-offs of consumer electronics (like "pionex" copies of pioneer equipment). that part of it is nothing new, but this practice of using multiple low performance dies to "simulate" a high performance transistor is something new. another potential source of knock-off semis is the distribution chain itself.... what does a distributor do if a certain date code or lot number of a particular component gets reported to have an unusually high failure rate, or out of spec lots? i would hope the distributor would return them to the manufacturer, but this may not always be the case. the part is already out there, and is for all intents and purposes, an original part, except it's from a bad lot or date code, and all the counterfeiter has to do is buy them cheap and resell them to other distributors that don't know it's a bad lot. when i get an OOB (out-of-box) failure on several of the same component with the same date code, i report it to the distributor, and mot reputable distributors will replace OOB failed components, and even sort replacements so you don't end up with a bunch of components from that same date code that you reported to them. usually distributors will report bad date codes back to the manufacturer, who will tell the distributor to return the entire remaining stock of that date code for credit. usually the manufacturer remelts the returned devices.

btw, wouldn't b-c capacitance (Ccb) be more directly related to die area than b-e capacitance (Cbe)?

We prefer to call it secondary market rather than grey market. No major manufacturer is going to sell off defective die, because it will only hurt their name and image in the industry. They usually mark these to be destroyed, and I believe that sometimes, unfortunately, they slip out the door.
This is a huge problem in industry, all sorts of bad lots show up at major manufacturers.

Pete B.
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