Multi-stage sigma-delta analog-to-digital converter with dither

摘要

Techniques to implement subtractive dither in a multi-stage ADC. Subtractive dither involves adding a first dither signal at a first node and adding a second dither signal at a second node (which can be the same as the first node), where the first and second dither signal combine and sum to approximately zero. By utilizing subtractive dither in a multi-stage ADC, the headroom requirements of a loop filter in a main loop of the ADC and the range requirements of a feedback DAC in the main loop can both be relaxed.