I'm trying to get t

_{r} ~60 ns here, but I get 129 or 27...

They do not say where they get V

_{GS}, so I can only assume this is my V

_{G(drv)}. Their C

_{iss} is also a little unclear because they never explain how C

_{gs} and C

_{gd} are calculated:

I have tried using both C

_{iss} from the datasheet (380 pF) and the calculated effective capacitance C

_{G(on)} from (Q

_{GS} + Q

_{GD}) / V

_{gp} = 1.83 nF. These are obviously wildly different values, but hey ho, I never get

*even close* to the observed (in simulation) ~60 ns rise time.

**Edit:** I'm sorry, I had an error in my simulation: the measured rise time should be ~

**50 ns**,

*not* 60.

**Edit2:** I've managed to prove (to myself - I'm sure this is

*obvious* to anyone who speaks math) that both of Vishay's methods for calculating t

_{r} produce exactly the same result when using the same value for the gate capacitance. The only problem is that using C

_{iss} it's about half of what it should be, and using C

_{G(on)} it's two and half times too large:

Not sure if that qualifies as progress, but it's at least nice to know.

**Edit3:** Maybe I'm calculating the gate capacitance during t

_{2} incorrectly; using (Q

_{GS} + Q

_{GD}) / V

_{gp} gives the Miller Plateau (t

_{3}) capacitance, which is where the gate capacitance reaches its maximum - but I'm interested in what happens

*before* that, at the threshold voltage. So perhaps Q

_{GS} / V

_{GS(th)} is more accurate for t

_{2}?

**Edit4:** I think that might have been correct; using Q

_{GS} / V

_{GS(th)} to calculate t

_{r} and C

_{iss} to calculate t

_{f} I get a rise time of 71 ns and a fall time of 33 ns, and plugging these into the DMC formula for power loss I get 0.037 W at 30 kHz and 0.012 W at 10 kHz. The power loss rises and falls with the value of the gate resistor by amounts that don't look totally wrong. I'll now try to double check this with additional simulation runs.

**Edit5:** Raising the gate resistor to 200 Ω (RG(tot) = 226 Ω) I get a 10 kHz switching loss of 0.019 W from the simulation, while the formula suggests 0.022 W. At 30 kHz the simulation gives 0.049 W, and the formula 0.067 W. Hmmm.