Best MOSFET for output stages

[Lars Clausen]

Sam9: good point...

It seems if you design a circuit with a BIAS point of the 100 mA, you can simplify your design slightly, by having no thermal tracking.

But if you were to use these devices in a Class A amp, or high BIAS amp, you would stilll need the thermal tracking.... so....

[Drafance007]

I just made one pcb for citation12 with irf540, and it seems to run smooth...But i don't have much of a power supply. What is the max. output power if anyone measured for mosfet citation ?

[millwood]

Originally posted by Drafance007
I just made one pcb for citation12 with irf540, and it seems to run smooth...But i don't have much of a power supply. What is the max. output power if anyone measured for mosfet citation ?

if your design is similar to Nelson's and IRF's, 60w for one pair of output device on 8ohm loads and 100w on 4ohm.

I always thought the citation is a good design: simple, decent (in performance) and inexpensive.

[Drafance007]

One other thing I have built many bipolar amps but this is my first MOSFET project. i am glad that it worked. I also have some IRF 530 devices, can this amp wor with them ?

[FACTOR]

HEY Guys BE COOL AND Listen to me
The IRF mosfets are very stable @40mA
These Mosfets donot require thermal compensation
As the Lateral type requires and hence no complex baising therefore only simple VGS of about 3.8volts is required to turn them ON

[Christer]

Originally posted by FACTOR
HEY Guys BE COOL AND Listen to me
The IRF mosfets are very stable @40mA
These Mosfets donot require thermal compensation
As the Lateral type requires and hence no complex baising therefore only simple VGS of about 3.8volts is required to turn them ON

If I have ever seen a lateral MOSFET amp with any temp.
comp. it is a rare exception. Rather, AFAIK they are so
commonly used because they don't require one, as for
instance Slone points out in his book.

It could be they would benefint from temp. comp. sonically,
though, if the bias current is far from the zero. temp. coeff.
ppoint.

[mcp]

Certain IRF mosfets (like the IRF 230 - the TO3 metal cans type) can be used without temperature compensation. For the newer types like IRFP240, thermal compensation is necessary.

Lateral mosfets (Hitachi 2SK1058/2SJ162) do not need temperature compensation. This is one of the key factors that distinguishes 2SK1058 mosfets from the rest.

[okkyn]

Originally Posted by mcp

Certain IRF mosfets (like the IRF 230 - the TO3 metal cans type) can be used without temperature compensation. For the newer types like IRFP240, thermal compensation is necessary.

Lateral mosfets (Hitachi 2SK1058/2SJ162) do not need temperature compensation. This is one of the key factors that distinguishes 2SK1058 mosfets from the rest.

Hi.. I'm resurrecting zombie thread

Is is possible to directly replace (with minor modification) those Hitachi mosfets with TO3 IRF230/9230??

Thanks
okky

[jackinnj]

Originally Posted by okkyn

Hi.. I'm resurrecting zombie thread

Is is possible to directly replace (with minor modification) those Hitachi mosfets with TO3 IRF230/9230??

Thanks
okky

The IRF parts need higher bias voltage and thermal compensation. The Renesas parts have lower transconductance, but better (easier to work with) thermal characteristics.

[okkyn]

Originally Posted by jackinnj

The IRF parts need higher bias voltage and thermal compensation. The Renesas parts have lower transconductance, but better (easier to work with) thermal characteristics.

Thanks jackinnj. I was referring to Michael Chua claim above that TO3 metal can IRF devices do not need thermal compensation. Is it true?