Linear Systems vs. Toshiba FETs

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tk@halmi

Well-known member
Joined
Jun 3, 2004
Messages
999
Location
Oregon, USA
Over the weekend I measured and sorted a hundred Linear System LSK170A parts and I noticed that they have a good bit more spread in Idss than the Toshiba parts. I had one as low as 1.7ma and another as high as 9.8ma in a batch of A grade fets so I am getting fewer matches (I aim for 5% or better). I never had that sort of spread with Toshiba parts.
 
I got them directly from Linear because I have been unable to source GR grade Toshiba parts in less than 1K quantities, at least not for a reasonable price. I called Linear up and the parts were here in three days. The pricing is better than the Toshibas even on 100 units ($1.13/ea).
To be fair the sample size was not the same as I used to work with. With the Toshibas I would get them in 200 piece lots. Then again the there were not so many out of spec pieces.
 
[quote author="Svart"]Do you get the feeling that the Linear parts will get better as their process gets streamlined?[/quote]

This was my first batch from LS so there is no trend I could talk about.
I am thinking of switching to J11X parts for input pairs. Yes, there is more noise (about the same as the NE5534), but I can get 1K of them for a hundred bucks.
 
I have tons of 2SK364's, which are identical chips to the SK170, if you need some. They are BL however.

EDIT: I have a fair number I already measured for Idss, so I could select some of the lower I ones if that's what you need. I've tended to pick out the higher value ones for various reasons.
 
Hi Brad,

Thank You for the offer, much appreiciated. I have a good number of decent matches so I wil be fine. The Linear parts seem to be on par with the Toshibas otherwise. It may be just their test/qc is not as good as Toshiba's.

Cheers,
Tamas
 
[quote author="tk@halmi"]Hi Brad,

Thank You for the offer, much appreiciated. I have a good number of decent matches so I wil be fine. The Linear parts seem to be on par with the Toshibas otherwise. It may be just their test/qc is not as good as Toshiba's.

Cheers,
Tamas[/quote]

Or maybe they don't make as many of them (highly likely at this point). It is after all a very simple sorting process, involving a quick measurement, unlike something that is measuring a picoamp and so forth.

I'm tickled that we have an alternate source, and a sustaining source for the dual SK389. I hope LIS prospers.

When I conversed with LIS via email the man said their dual parts should actually be quieter than the Tosh because of the interdigitated construction. I didn't press him on the whys and wherefores of this assertion, or in what frequency range the alleged superiority would manifest, but I would be fascinated to know, if anyone has gotten some data. I've been too damn busy, and as well am sitting on about a thousand 2SK389V's that I bought when Borbely confirmed Toshiba had stopped making the part. Most of those will probably go to the crematorium with me, but they confer a sense of security in the meantime.
 
I dont know if they ship to U.S, but for us in Europe, www.elfa.se/en stocks the Toshiba's SK170 at fair price.
the price is in Euro's and if you buy 100 or more its 40cent's a piece

johan
 
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