I need an LC tank that's resonant at 107 KHz. It will be "pumped" by a mosfet and have about 60 volts p-p across it. L is about 75 uH, so Xl is around 50 ohms. Peak inductor current is half an amp or so.
I need to hit close to 107KHz in production, and available small shielded inductors are mostly +-20%. So, how to tune it?
Trim caps and varicaps are too small, and 60 is a lot of volts.
Use a trimmable pot core, but that's a custom part PITA. RF type trimmable inductors look too wimpy for this frequency and current.
Make a capacitive DAC, maybe 4 bits, c values weighted 1-2-4-8. Switch the caps across the LC tank with a dip switch or relays or SSRs, gives 16 tuning steps. The bigger caps have to be pretty accurate to keep the steps sorta uniform.
Put pin sockets on the board for three or four caps, and manually plug in assorted film caps, like those nice WIMA parts.