iXYS linear power mosfet

[Avlin]

Hi !

I'm new on this forum

I want to now if IXYS linear 2 mosfet series are good rated for audio amplification since they are designed for "linear amplifier".

IXYS Product Portfolio | Power Devices

How could we now if a lateral structure mosfet is good ?

what are the main criteria ?

Is the 2sk1058 the best ? mosfet are evolving all months, but only in switching applications (trench fet gen 2 - hexfet - GaN ...)

I'll eventually build a class a single ended preamp this month

thanks.

[abraxalito]

Those FETs might make great output stages (very high power handling and excellent low thermal resistance) but would not be a great choice for preamp duty - capacitances look very high. No P-channel parts listed either.

As to whether 2SK1058 is best, it depends what your evaluation criteria are - ruggedness (for example) or value for money? Its switching that has the volumes these days, which explains why the 2SK has been around unchanged for decades.

<edit> ooops, forgot to say - welcome to diya!

[Avlin]

oops I wanted to say amp and not preamp, and in single ended class A there is no need for P channel.

so as I understand, since there is no evolution in lateral structure mosfet, the 2sk remains a good choice ?

maybe i could build an experimental amp with 2sk1058 and try another mosfet later

so i should search linear mosfet with low capacitance ?

thanks for your quick response.

[woody]

You might also want to look at the power jfets from Simisouth they have a lot less
distortion but are expensive.

[abraxalito]

Originally Posted by Avlin

so as I understand, since there is no evolution in lateral structure mosfet, the 2sk remains a good choice ?

A good choice amongst laterals yes. But then you're really looking at such a narrow range of available parts that its almost Hobson's. You've decided that laterals suit your application best? In a class A application where the quiescents are huge (relatively) I think the relative disadvantages of verticals are much reduced. Temperature stability for one hardly matters as the amp actually gets cooler when playing

so i should search linear mosfet with low capacitance ?

Lower capacitance is easier to drive, all other things being equal. MOSFETs usually have 3 capacitances specified on the datasheet, which ones are important depends on whether you're using it common-drain or common-source.

Originally Posted by woody

You might also want to look at the power jfets from Simisouth they have a lot less distortion but are expensive.

Well if we're really in price-no-object territory, how about this Cree one?

CREE | SiC MOSFET

[ANADIGIT]

Used in Gamut D200I SOT-227 case manufactued from Microsemi but I think it's look like IXYS, too

"Push-Pull" for push und "Push-Pull" for pull (like Gamnut) - whats the right name?

Thanks
Anadigit

[Avlin]

Originally Posted by abraxalito

You've decided that laterals suit your application best? In a class A application where the quiescents are huge (relatively) I think the relative disadvantages of verticals are much reduced.

may vertical structure mosfet be a good choice for a single ended class A amp ?

Originally Posted by abraxalito

Temperature stability for one hardly matters as the amp actually gets cooler when playing

hmm it is easier to find a very good mosfet with better thermal stability than a lateral structure.

Originally Posted by abraxalito

Well if we're really in price-no-object territory, how about this Cree one?
CREE | SiC MOSFET

according what you says GaN mosfet may be better (or actually trenchfet Gen 3) : (page 3)

http://www.irf.com/product-info/ganpowir/GaNGeneral.pdf

@ ANADIGIT : seems the SOT 227 good for thermal stability

very interesting and nice forum

but 4:00 am for me (france), i'll go to sleep

ps : what about mosfet package parasite inductance ?

[abraxalito]

Originally Posted by Avlin

may vertical structure mosfet be a good choice for a single ended class A amp ?

Yeah, I tend to think so. Better because its cheaper and there are more sources out there. I would guess that Nelson Pass thinks so too. Why not go ask him as he's the man with the most experience in this department?

according what you says GaN mosfet may be better (or actually trenchfet Gen 3) : (page 3)

GaN FETs are new to me. Just from a quick read it seems their FOM (figure of merit) is based on Rds(ON) which is of zero consequence in linear applications. So for now, I recommend sticking with the traditional silicon based FETs for audio. If I was investing, I'd go with IR's Si-substrate approach rather than Cree's as it looks more cost effective.

ps : what about mosfet package parasite inductance ?

Not really an issue at audio frequencies with a linear amp. Big concern for switching amps though.

[ANADIGIT]

Why didn't Class-A amplifier havn't use SOT-227 in their product ?

[WuYit]

Hi,
on what basis is the entire product family entitled "linear"?