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KTA1659A and KTC4370A

JoseHH said:
These type B parts had a large breakdown voltage and as far as I know, only Toshiba produced them. KEC and UTC acquired some of the processes that other manufacturers discontinued, but it seems that they are not making all the breakdown types that Toshiba had.

You don't have to test your parts to destruction. Only try to approach the SOA DC line like I marked in the figure above, and see that the parts can pass the specified current at 30V for a few seconds and then turn it off (mount the part with grease on a heat sink like you would in an actual application).
As a second test, see that the breakdown voltage (current limited to, say 500 microamperes) is above the 180V for the KTA4370A type and above 160V for the KTA4370. These tests will not degrade the parts. With that, you will know if the parts will likely sustain their use in your amplifier.

I dont have the transistors with me now. My fixture to test the SOA and these KEC parts are in Bangkok. When in go there at the end of the year, and I can test the breakdown voltage and see how much current they pass at some 100V or 120V. But you will probably be done with your tests before me :beerchug:
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did you get to test these parts yet? I too bought a bunch and would love to see how they hold up to your testing.
 
Nashou66 said:
did you get to test these parts yet? I too bought a bunch and would love to see how they hold up to your testing.
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Hi there,

I measured the collector-emitter breakdown voltages for 6 pieces of the parts KTA1659A, KTC4370A and for 6 pieces of the Toshiba 2SA1306A. All the parts were rank Y
Vceo (BR) V
SampleKTA1559A Y (production data 105)KTC47370A Y (production data 526)2SA1306A Y (production data8k)
1282196259
2241195274
3289200318
4285197297
5244193274
6254197267

I tested one piece of the KTA1659A and one piece of the KTC4370A, at 125V and 95mA continuous current during 12 seconds . They passed the test without blowing. I did not continue holding the current for longer because the part are dissipating 12 W of power under these tests and they get too hot to keep them passing that current indefinitely. For comparison I also tested one of the Toshiba 2SA1306A and it also passed this test without damage, getting similarly hot to the KEC parts.
 
Yes, I think they are good, at 125V the SOA figure suggests that these parts should hold just around 90 mA so the measurements match or even exceed a bit what i see in the datasheet. Interestingly the C-E breakdown voltage for the NPN parts was lower than that for the PNP parts. I wonder if this is general or just for these oarts only. Unfortunately I do not have any 2sc3298 to measure for comparison of the breakdown voltages.
 
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I had the chance to buy 4 pairs of the KEC KTD2061Y and KTB1369Y. I dont have a use for these, but a local shop here in Bangkok had these 8 transistors and were not expensive so I bought them out of curiosity. These have an isolated TO220 format just like the KTC4370A. According to the datasheet these are pretty hefty transistors with ft of 100 MHz and 180V maximum Vceo. Their SOA plot shows that at 100V they are supposed to pass 200 mA DC as long as they are helt at 25 C.
for the KTD2061Y I have measured the collector to emitter breakdown voltage and got 207V, 219V 222V and 225V.
The KTB1369Y gave me Vceo values of 234 V (2 pieces) and 245V for the other two.
I thought that this information complements what we have for the KTA1659A and KTC4370A so I add it on this thread.
 
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