is the switching frequency of the EPC development boards restricted to a certain frequency? Can they operate at 1.5 MHz or 2 MHZ?
The operating frequency of our demo boards are based on our control system. Our devices work over 400kHz to ~2Mhz so there is no problem if you use your own controller to adjust the frequency. Working at higher frequency you will need to be very careful of layout since the effect of parasitic inductance will be more obvious at high frequency. The other thing you need to consider is even though GaN power devices have very small Qg and Qoss, the switching loss will still be higher than low operating frequency. Working at higher frequency you can reduce ESR of buck inductance, so you can reduce loss.