KSC2690A and KSA1220A

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mt490

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Joined 2010
synonymous said:
How well do these compare with the KSC/KSA variety?
Consistent in gain etc?
I'm looking for a good SMD equivalent..
S
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I find the ex-Sanyo stuff has been relatively consistent in batches.

As for SOA, yeah the dies in the 160V devices are small. It is pretty much a trade off between Cob and SOA. You can get devices with more SOA like the 2SB1275/D1918 but they are comparatively heavyweight, much like TTA(C)004.

I use the 100V devices in CFP configuration, only with 37V rails. 2SA2205 and C6099 which are NRND in those packages, or 2SB1215/D1815. However in a CFP the value of low as possible Cob is important and the driver idle current is a lot lower than in EF.

Nexperia also do 100V devices as PHPT61002*, but I have never tried them. It also comes in NPN+NPN PNP+PNP and NPN+PNP copack varieties. I mused about trying them as a bias coupling device but never bothered. However with these you'd have to do your own tests to check where their SB limits will be - I'm not sure if their LFPAK56 package's copper sandwich construction practically inhibits SB, or if they just don't bother in their datasheet because they're not expecting people to use it where SB is a problem.

When designing around SMD devices for this, it's pertinent to consider the 100ms pulse rating rather than just looking at DC. Whilst you do need to make sure the dissipation is sufficient, because the manufacturer ratings are often on relatively small naturally cooled lands you do gain a lot by differentiating. On something like a TO-252 if the device were actually plotted using Tc 25 the curves look very different, so there is a lot of scope for increased cooling over the Ta 25 lines.
 
Bonsai

Bonsai

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PB2 said:
I'm trying to buy these:
KSC3503 only D beta grade is available
KSA1381 E grade is available

Anyone found a source for both type in E's?
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This has been an ongoing issue for years. In the sx-Amp You had to match them and the guys were already struggling in 2013 with this issue.

On the nx- amp and later designs, I use beta enhancers so the hFE deltas between the complements are less exposed.

I think the biggest issue we will face in the coming years will be the lack of decent complementary VAS devices - high Vce, low Cob, flat hFE vs Ic etc etc.

I don’t see anyway out of this other than to use a cascode since there are plenty of high voltage bipolars around and feed it with a beta enhanced low voltage stage.

Another challenge awaits us . . .
 
Mark Johnson

Mark Johnson

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Joined 2011
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Bonsai said:
On the nx- amp and later designs, I use beta enhancers so the hFE deltas between the complements are less exposed.
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Hi, would you please circle the "beta enhancers" in green, on the attached nx- amp schematic? Thanks very much.

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PB2

PB2

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Joined 2004
linkedin.com/in/petebasel
Mark Johnson said:
Good news: they're in stock & on the shelf, today. Buy a few tubes now when you can get them easily.

_
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I wrote this on another thread, I'm not in the business but these parts coming back seem to support the claim:

I was told, probably 30 years ago, that semi companies "set up" the fab line to do
a run of wafers for a given part type. I don't know how many they make but I'd
assume it is based on some minimum and perhaps anticipated large orders. Those
parts go out to distributors and it could be several years before it comes around
again to make that particular part number. Obviously, parts that are discontinued
are not in the lineup for production.

Seems they were a bit late but finally came around to producing them again.
 
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