Finding spice models for the 2N7000 is easy, being the only problem that there are so many. I used the typical Coss of 2N7000 (11pf) and subtracted from C1 in the Sokal 2001 formulas.
In order to stop working at the PC for so long, I started using the calculator more often to find optimum parameters and just do a short simulation at the PC. Here's the print out from the calculator.
QL is the Qload of the circuit, K1 is the ratio of XL1 to XC1 (unadjusted) (mentioned in Sokal 2001), one could do some iterative calculations but a simple adjustment seems good enough.
Simulations, unfortunately are not handled (yet) by my HP42S... so here's the ngspice output.
|Spice output using 2N7000 Vgs=5V|
There was something wrong! After having a closer look at the datasheet of the 2N7000, the drive voltage was clearly a problem. My system is 5V only (Vcc and Vdrive) and it is clearly insufficient to fully drive the 2N7000. Once the drive was changed to 12V the waveforms looked much better.
|2N7000 with VGS=12V|
Since the system will be 5V only I had to find a logic level drive MOSFET, the ones I had available were IRLD024 or IRLR024N. Unfortunately there are no spice model available for the IRLD024 (Vishay or IR), so I will use the second one (IRLR024N) for simulation and the first one for the final circuit.
|Class E with IRLR024N|