Rail-to-rail input-stage with linearly tunable transconductance

A new technique for the rail-to-rail input stage is proposed. The proposed technique is based on the master-slave approach of complementary MOS transistor pairs. The input transconductance is linearly tunable over a large range and is almost constant for the rail-to-rail common-mode range. The effectiveness of the proposed technique was verified by simulations using a standard 0.18 m CMOS process.