I'm going to use speaker connected to internal Class D amplifier in WM8998 in my PCB. Power source of my PCB is Li-Pol battery with 3.2-4.1V range or external 4V adapter. Audio codec speaker power pins(SPKVDD) should be connected to battery according WM8998 datasheet.
Do I understand correctly that WM8998 doesn't consider battery voltage to stabilize PWM amplitude and output volume will be depends not only on value in register OUT4R_VOL/OUT4L_VOL but also on current battery voltage? Is it possible to avoid this dependence on battery voltage without using an additional DC/DC converter for SPKVDD? WM8998datasheet