I am trying to find the value of K for an IRFAC30 and IRFAC40 in this well known model: ID = K ( VGS - VP )^2 which is in the active region.
I need this to predict the gate voltage swing in my design. I am having trouble finding enough information in the data sheets to do this. Also I was not able find a spice model for these in the file downloaded at:
The gfs entry is not useful for this because (VG-VP) for this parameter is not given. Not even VG is.
I cannot infer if from the RDS(on) parameters because VGS for both of these is the same. Otherwise I might have been able to solve for the two unknowns VP and K with these two RDS(on) entries.
How is this supposed to be done? Can it be done?