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.

[1]  M. A. Copeland,et al.  Design and realization of a digital /spl Delta//spl Sigma/ modulator for fractional-n frequency synthesis , 1999 .

[2]  K. Hosseini,et al.  Mathematical analysis of digital MASH delta-sigma modulators for fractional-N frequency synthesizers , 2006, 2006 Ph.D. Research in Microelectronics and Electronics.

[3]  Ron-Yi Liu,et al.  A 5.8-GHz delta-sigma fractional-N frequency synthesizer for IEEE 802.11a applications , 2003, ASICON 2003.

[4]  M. A. Copeland,et al.  Design and realization of a digital ??? modulator for fractional-n frequency synthesis , 1999 .

[5]  B.-S. Song,et al.  A 1.1-GHz CMOS fractional-N frequency synthesizer with a 3-b third-order /spl Delta//spl Sigma/ modulator , 2000, IEEE Journal of Solid-State Circuits.

[6]  Kari Halonen,et al.  A 4 GHz ΔΣ Fractional-N Frequency Synthesizer , 2000 .

[7]  Zhipeng Ye,et al.  Reduced Complexity MASH Delta–Sigma Modulator , 2007, IEEE Transactions on Circuits and Systems II: Express Briefs.

[8]  Bram De Muer,et al.  On the analysis of ΔΣ fractional-N frequency synthesizers for high-spectral purity , 2003, IEEE Trans. Circuits Syst. II Express Briefs.

[9]  Chauchin Su,et al.  A spread spectrum clock generator for SATA-II , 2005, 2005 IEEE International Symposium on Circuits and Systems.

[10]  H.R. Rategh,et al.  A CMOS frequency synthesizer with an injection-locked frequency divider for a 5-GHz wireless LAN receiver , 2000, IEEE Journal of Solid-State Circuits.

[11]  Bang-Sup Song,et al.  A 1.1 GHz CMOS fractional-N frequency synthesizer with a 3b 3rd-order ΔΣ modulator , 2000 .

[12]  Kari Halonen,et al.  A 2 GHz ΔΣ fractional-N frequency synthesizer in 0.35 µm CMOS , 2000 .