The STM32F7 onboard DAC is only 12 bits. I only need mono audio input. Suppose I drive the left ADC input directly and the right from an op amp gain stage of say x16 and then combine the lowest 4 bits of R with left-shifted L? Do I have something akin to a 16 bit ADC? Should I diode-clamp the output of R so I don't generate overages to the ADC?