OPS complimentary MOSFET IRFP240/IRFP9140 and IRP340/IRFP9240

Joined 2011
Paid Member
Hi all,

Have a question here:
If IRFP240 and IRFP9240 are considered complimentary, why is that IRFP9140 actually seems like a better complimentary mosfet?

Looking at the datasheet:
IRFP240, Qg=70, Ciss=1300pF, Id=12A, Pdis=150W, Rds_on=0.18, $2.95, Soa at 40V I=11A/sqrt2=~7.7A
IRFP9140, Qg=61, Ciss=1400pF, Id=-15A, Pdis=180W, Rds_on=0.2, $2.63, Soa at 40V I=8A/sqrt2=~5.6A

Note the Rds_on is 0.18R and 0.2R which is pretty close in my opinion. Also, Qg is 71 vs 61.

Another pair I was comparing was IRFP340 vs IRFP9240:
IRFP340, Qg=62, Ciss=1400pF, Id=6.9A, Pdis=150W, Rds_on=0.55, $5.17, Soa at 40V I=6A/sqrt2=~4.24A
IRFP9240, Qg=44, Ciss=1200p, Id=-7.5A, Pdis=150W, Rds_on=0.5, $4.72, Soa at 40V I=7A/sqrt2=~4.94A

Their Rds_on are 0.55R and 0.5R.
Last edited:
Joined 2011
Paid Member
I was able to find IRFP340 and IRFP9240 on Mouser, but they are pricy, at around $5 each
I think that they are great pair because of their Rds_on is higher at 0.5R
Another pair I was looking at is IRF510 and IRF9520 with Rds_on 0.54 and 0.6, and they are really cheap but not as powerful