IRFP140N vs IRFP240

As stated above, they have different voltage ratings but the N series devices are usually not really suitable for our purposes as they are primarily a switching fet and have a much smaller die (so they have much lower power dissipation capabilities) compared to the standard range. This also allows the N series to be significantly cheaper. Given the 2 devices listed, I would definately use the IRFP240.

Joe Berry

2001-03-15 6:15 pm
I wouldn't shy away from using the IRFP140N in a lower-voltage (40Vds or less) high-bias application where only N-channel MOSFETs are used, such as in the Pass Zen amplifier projects.

However, I wouldn't recommend them for projects requiring a complementary output stage, as last time I checked, the P-channel counterpart to the IRFP140N was more than twice as expensive. The IRFP240 and IRFP9240 are much closer in cost.
Thank you, i understand the difference in the size of the die now. In fact for me the IRFP140N would cost 1,50Euro, the IRFP240 1,40 Euro, the IRFP150N i used is 1,95 Euro, the IRFP150 1,40 Euro.

I know the datasheets for IRFP150N/240.

What i don´t know is the Quality in relation of the THD they cause. In the ZEN artivles Nelson says the lower the voltage the bettter, but nothing about this "N".

OK, if there is nothing against i´ll take IRFP240.

btw. i will use them for the ZEN variations, experiments with small alephs etc.
The lower voltage devices do contribe less THD but as stated above, I wouldnt bother using the N series devices as you'll either have to use more of them or x50N devices whose specs aren't as favourable as x40 devices... If you can get hold of IRFP140 devices they are the pick of the litter for lower voltage amps but they are becoming harder to obtain as the N series devices take over.
> (Example: IRFP044: Ciss = 2500pF, IRFP044N: Ciss=1500pF, RdsON is the same (0.02Ohm))

You forgot to mention that the N type is specified at 120W, with thermal resistance of 1.3°C/W, whereas the 044 is specified at 180W, with 0.83°C/W.

> Today I have tested APT5015BVR N-Fet. I think it was as good as IRFP240.

In my opinion a even better alternative, be it more expensice / less available :