How can the HV816DB3 demo board be integrated into a design without creating noise?
The sound is normally produced by the capacitors if the demo boards is an X7R type. To avoid the noise, we suggest using either an NP0 or foil capacitor. You can improve it by replacing one capacitor on top and a second exactly on the other side of the PCB (the capacitor oscillation is vertical and transferred to the PCB). It may help to add a series resistor to the foil to slow down the rise and fall times, however, this can increase losses and needs to be further tested.