IXTX200N10L2 Mosfets

Hi,

As I could check, the IXTX200N10L2 is designed for linear operation while irfp240/irfp140 are designed for switching.
Current industry is focussed on switching applications, so the cost will be much lower for these devices due to high volume produced.

In addition, the basic parameters such as Vds, Id and power dissipation are not even closer.
Do you have the schematics? We can, at least, check the basics (V, I and P) and then check other parameters such as the capacitances etc.
 
I would check Vth, transconductance and other transfer properties.

The "linear" mosfets generally have a larger die, to allow for better thermal handling etc.

I would say that even pricey, you get away with fewer as they likely can be driven closer to the thermal limit

mosfets for switching purposes can not be driven to the linit.