You did not explain the function of your circuit. Pitch is the frequency of sounds.
Is it a class-D amplifier that uses PWM to make its waveforms very efficient?
Why do you want the extremely low frequencies of 1mhz - 10mhz? They are not sounds, instead they are very slow vibrations.
Chipsets are made when there are millions of a certain circuit needed. You did not explain your requirements for a circuit so maybe nobody else needs it, then there is no chipset available.