Odd SIT/vFET 2SK2087C

Did they look like the right packages at least?
Hey Haiqu, this was what came through, shape yes, other bits no and only 1 of them
 

Attachments

  • Screenshot_20220506-133805_WhatsApp.jpg
    Screenshot_20220506-133805_WhatsApp.jpg
    139.8 KB · Views: 168
What did you think? Surface feels very rough (sand blasted)?!
Please see also these arrows for the differences.

Ali picture:
Bildschirmfoto 2022-05-08 um 16.21.21.png

What I got:
Bildschirmfoto 2022-05-08 um 16.23.26.png

A quick test withe the DCA75 (two of ten):
Fake_Or_Not_2SK2087C_id-vgs.jpg
Fake_Or_Not_2SK2087C_id-vds.jpg

Any hints for measuring them right?
Did anyone a data sheet handy
 
FYI:
ds: about 1.5ohm;
gs/gd: about 0.41v.
 

Attachments

  • 9C7B41A9-CA79-4733-AC98-13079590E72C.jpeg
    9C7B41A9-CA79-4733-AC98-13079590E72C.jpeg
    394.3 KB · Views: 122
  • 07912A5C-2446-428D-BCD7-11FE123B9C4D.jpeg
    07912A5C-2446-428D-BCD7-11FE123B9C4D.jpeg
    411.8 KB · Views: 124
  • 02C1FF57-EE69-493C-AE4B-6311AC30EF6B.jpeg
    02C1FF57-EE69-493C-AE4B-6311AC30EF6B.jpeg
    398.1 KB · Views: 123
Last edited:
Try to make a SPICE model, by SIT Modeler on the basis of iTracer's Plot, but it's hard to get precisely fitted, so here is my best result:

*Multisim-Prooved PSPICE-compatible
*--------------------------------------------------
*2SK2087C
*GENERATED BY SIT MODELER @ AUDIOMAKER.TECH
*MODEL RANGE: 20V, 2A
*--------------------------------------------------
.SUBCKT 2SK2087C D G S ; Drain Gate Source
+ PARAMS: MU=100 X=3.53 K=0.376 N=0.69 VCT=0.82 RG=2MEG
*--------------------------------------------------
B1 D S I=K*PWR(URAMP((V(G,S)+VCT)+(N*LN(V(D,S))+(V(D,S)/MU))),X)
FOR MULTISIM COMMENT OUT ABOVE LINE () AND UNCOMMENT NEXT LINE
*B1 D S I=K*PWR(MAX((V(G,S)+VCT)+(N*LN(V(D,S))+(V(D,S)/MU)),0),X)
R1 G S {RG}
CGS G S 0P
CGD G D 0P
CDS G S 0P
.ENDS 2SK2087C
*--------------------------------------------------



or (might be LTSPICE)


*--------------------------------------------------
*2SK2087C
*GENERATED BY SIT MODELER @ AUDIOMAKER.TECH
*MODEL RANGE: 20V, 2A
*--------------------------------------------------
.SUBCKT 2SK2087C D G S ; Drain Gate Source
+ PARAMS: MU=100 X=3.53 K=0.376 N=0.69 VCT=0.82 RG=2MEG
*--------------------------------------------------
*B1 D S I=K*PWR(URAMP((V(G,S)+VCT)+(N*LN(V(D,S))+(V(D,S)/MU))),X)
FOR MULTISIM COMMENT OUT ABOVE LINE () AND UNCOMMENT NEXT LINE
B1 D S I=K*PWR(MAX((V(G,S)+VCT)+(N*LN(V(D,S))+(V(D,S)/MU)),0),X)
R1 G S {RG}
CGS G S 0P
CGD G D 0P
CDS G S 0P
.ENDS 2SK2087C
*--------------------------------------------------



1652113047544.png
 
Well, in an unexpected twist, I seem to have received what I actually ordered on Aliexpress. What’s more, I’m fairly certain it was the same vendor who has been sending the to-220 singles. Weird. I glanced back, and these appear similar to what Carsten.Witt received. They’re definitely new stock. I don’t have any tracing capabilities, but will measure what I can once I’m back home.
 

Attachments

  • 074FAB20-CD18-435E-8D86-2A011B5EC585.jpeg
    074FAB20-CD18-435E-8D86-2A011B5EC585.jpeg
    246.7 KB · Views: 196
<<iTracer - comments and suggestions are welcomed for this newly-developed tracer system.>>

OK, you asked for it... 🙂

The curves Id=ƒ(Vgs) in post 94 are suitable only for the regular FET, but not for the SIT.
Waste of time.
For the SIT (triode type char-s) we need family of output char-s, as in post 89 and post 1.
BUT, if you are planning to build an amp with 50...60V (±25...30V) supply, you will need to
scan your transistors in that Vds /ce range, in fact, even more than that: 80+V.
Or more, if you insist...
For the Id current - the tracer must provide the max expected current amplitude into the
speaker (3...4 A, whatever...)

And what is your curves tracers give us?
post 89 - only ~15V
post 1 - left pic ~10V (horiz /div 2V×5 grid div), right pic ~25V (horiz /div 5V×5 grid div), on
a bottom ('x' coord)! I am looking at the last Vgs curve, where it reaches some level of Id ~100...200mA...
And this type of scans is typical in practically all measurements which were presented here and
elsewhere on the Internet... They are SIT curves, but not of any use in the design process...

People are buying kindergarten toys, from the developers who substitute SW coding skills for
the lack of knowledge in analog electronics / transistors, and I do not even mention SITs...
 
<<iTracer - comments and suggestions are welcomed for this newly-developed tracer system.>>

OK, you asked for it... 🙂

The curves Id=ƒ(Vgs) in post 94 are suitable only for the regular FET, but not for the SIT.
Waste of time.
For the SIT (triode type char-s) we need family of output char-s, as in post 89 and post 1.
BUT, if you are planning to build an amp with 50...60V (±25...30V) supply, you will need to
scan your transistors in that Vds /ce range, in fact, even more than that: 80+V.
Or more, if you insist...
For the Id current - the tracer must provide the max expected current amplitude into the
speaker (3...4 A, whatever...)

And what is your curves tracers give us?
post 89 - only ~15V
post 1 - left pic ~10V (horiz /div 2V×5 grid div), right pic ~25V (horiz /div 5V×5 grid div), on
a bottom ('x' coord)! I am looking at the last Vgs curve, where it reaches some level of Id ~100...200mA...
And this type of scans is typical in practically all measurements which were presented here and
elsewhere on the Internet... They are SIT curves, but not of any use in the design process...

People are buying kindergarten toys, from the developers who substitute SW coding skills for
the lack of knowledge in analog electronics / transistors, and I do not even mention SITs...

Sure, you probably need the PyPSUcurvetrace which is developed by DIYAudio member mbrennwa.
The high current/Voltage is not what iTracer features, and that's why PyPSUcurvetrace is there and.... SMUs by keithley or Tektronix (maybe $4000USD?).
And hey, please think about the cost-effectiveness, for DIYers/hobbyist, there is a huge price gap between hobby-grade "toy" and professional SMUs.

The iTracer is dedicated to provide a balanced-capability solution for its price band, which I think is near-vaccum.
By the way, please don't judge the tracer simply by its current/voltage capability, but I am not gonna introduce features here again.

Tracing, Matching high power devices like 2SK2087 is never an easy, cheap job for any solution/devices even SMUs,
so I just let the "toy" do its best, thank you for your feedback/comments🙂 , yet something like 80+Volts is not what iTracer designed to do.
Of course it would definitely be better if the tracer can do that, but this is for sure another story as a whole-new, powerful, costly circuitry is needed.
 
Well, in an unexpected twist, I seem to have received what I actually ordered on Aliexpress. What’s more, I’m fairly certain it was the same vendor who has been sending the to-220 singles. Weird. I glanced back, and these appear similar to what Carsten.Witt received. They’re definitely new stock. I don’t have any tracing capabilities, but will measure what I can once I’m back home.
Those are the exact same parts I received today, right down to the batch number and Glad Wrap packaging. I'm VERY pleased.
 
  • Like
Reactions: codyt