A low-cost charge injection mechanism may enable oversampling to be used on low frequency signals by injecting dither noise into the ADC input. The dither noise can reduce the quantization noise allowing even direct current (DC) signals to be oversampled correctly. A low-cost charge injection mechanism can also be used to improve the ENOB by characterizing the ADC and digitally correcting the converted signal for non-linearity errors such as INL. Reducing INL errors may also allow a higher degree of oversampling to be used to further improve the ENOB.