This　paper　proposes　new　structures　of　multi-stage　noise-shaping　(MASH)　sigma-delta　ADC　by　applying　second-order　noise-coupling　technology　to　conventional　MASH　modulators.　The　proposed　architectures　take　advantage　of　the　extra　noise-coupled　path　to　achieve　a　second-order　noise-shaping　increase　as　well　as　save　the　number　of　active　devices.　Theoretical　analysis　and　system-level　simulation　are　given,　and　the　implementation　of　the　modulators　is　also　analyzed.　The　new　structures　are　suitable　for　broad-band　applications.