Hardware Simplification to the Delta Path in a MASH 111 Delta–Sigma Modulator

A MASH 111 delta-sigma modulator (DSM) is widely used in a fractional-N frequency synthesizer. This brief presents a low-complexity delta-path design in a MASH 111 modulator by simply recoding all carry output signals from accumulators. Compared with the prior approach, the hardware complexity of the proposed delta path is reduced to 53.4% of the prior approach. For frequency synthesizers with limited channels or for the pipelined DSM with accumulators possessing long word lengths, this saving is significant.