Rail-to-rail super class AB CMOS operational amplifiers

Novel class AB single-stage operational amplifiers are presented. They feature rail-to-rail operation owing to the use of floating-gate input transistors. Initial charge of the floating gates is removed during fabrication, without any post-processing. The amplifiers arc fast, simple, and able to operate at low supply voltages. They are highly power efficient owing to the enhanced (super) class AB operation based on adaptive biasing and local common-mode feedback. A 0.5 mum CMOS implementation shows rail-to-rail operation with slew rates of about 40 V/mus for a load of 80 pF and 144 muW of quiescent power consumption.