I have heard that an internal ADC used in the delta sigma (DS) ADC is a low resolution one, but the internal DAC needs to be as accurate as the whole DS ADC. Assume we want to design a 10-bit delta sigma with a 3-bit internal flash ADC. we know that offset of flash ADC could be less than Vref/2^3. But what about DAC, its offset should be less than Vref/2^3 or Vref/2^10?