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petoluk

petoluk

Member
Joined 2013
Weeell, but the SJEP data sheet gives the capacitances at Vds = 100V / Vgs = 0V, while 2SK1058 is quoted at Vds = 10V / Vgs = -5V. If you correlate the data based on the charts (at least for Ciss, there's no Coss / Crss chart in the 2SK1058 data sheet), you get:

SJEP120R100
Ciss = ~850pF

2SK1058
Ciss = ~330pF x 6 = 1,980 pF

Still a lot, but not 5.5x as much, "only" 2.5x. ;) So perhaps 4 in parallel selected for the highest yfs would just about cut the mustard... (2SK286, with 1.4 typ / 2.5 max yfs and Ciss of ~400pF, could still be a cheaper / easier to find option.)
 

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petoluk

petoluk

Member
Joined 2013
P.S. Found the capacitance charts for the 2SK1058 in TO-3, née 2SK135, so at comparable Vds / Vgs (10V / 0V), we'd get:

SJEP120R100
Ciss = ~850pF
Coss = ~300pF
Crss = ~300pF

2SK1058
Ciss = ~330pF
Coss = ~310pF
Crss = ~10pF
 

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A

Antoinel

Member
Joined 2011
F8 is innovative, an example of unmatched simplicity and efficiency-performance.

Let's broaden the view of this innovation by considering a classical power amp which has the familiar 3 stages. An input diff amp, followed by the last voltage amp and followed by complementary buffers. Let's do unto this classical amp what Mr. Pass did to J2.

Disable one semi from the the input diff amp, and return loop feedback to the source or emitter of the remaining semi in diff amp. Maybe easier written than done; but its an experiment!

Best
Anton
 
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