Does the current rating of a mosfet take into account all maximum circumstances under normal operating circumstances? e.g., basically if it says X amps and I run it < 80%X or so will everything be ok? i.e., does it essentially include the power dissipation in that value too(in the sense that P_max = X*Rds_ON)?
Just not sure if I actually need to calculate anything else if I'm running it under "normal operating conditions"? I'm just trying to find some decent, but not too derated, mosfets(actually H-Bridge) for motor control of about
15A but not sure if they can handle the power dissipation but not sure if the max current rating takes that into account or not. I do see the max power dissipation on the data sheet but I'm a bit confused at how they got it:
Dual N & P-Channel PowerTrench® MOSFETN-Channel: 40V, 20A, 24m? P-Channel: -40V, -20A, 54m? Features Q1: N-Channel ??Max rDS(on) = 24m? at VGS = 10V, ID = 9.0A ??Max rDS(on) = 30m? at VGS = 4.5V, ID = 7.0A Q2: P-Channel ??Max rDS(on) = 54m? at VGS = -10V, ID = -6.5A ??Max rDS(on) = 70m? at VGS = -4.5V, ID = -5.6A ??Fast switching speed ??RoHS Compliant
How can it be both 20A and 9A?
Thanks, Jon