A newrail-to-rail opamp with bulk-driven input stage and interleaved class-AB ouput stage

This paper introduces a fully differential rail-to-rail input/output CMOS operational amplifier consisting of a bulk-driven input stage and an interleaved class-AB output stage. The input stage features a partial positive feedback loop to improve the gain and gain-bandwidth-product. Post-layout simulated results have shown that the proposed opamp, implemented in standard 65nm CMOS technology and with a 1.2V supply, obtains an open-loop DC gain higher than 72dB and gain-bandwidth-product above 15MHz when a 6pF load is connected to the differential output.