Artigo muito claro sobre as tecnologias de conversão D/A:
R 2R Ladder DAC vs Sigma-Delta DAC vs DSD DAC
PCM DAC may be based on either resistor matrix (R2R) or sigma-delta modulator (SDM). Last one is most popular. But sometimes we can read that some people prefer R-2R DACs. DSD DAC is alternative both PCM DAC types. Read about comparison of the DAC types, its advantages and disadvantages.