Achieving rail-to-rail input operation using level-shift multiplexing technique for all CMOS op-amps

This paper presents a new design approach which can convert any CMOS operational amplifiers to have rail-to-rail common-mode input capability by utilizing few additional hardware elements. The proposed circuit can operate over a wide range of supply voltages from 1-volt to the maximum allowed for the CMOS process, without degrading the ac and dc performances of the amplifier in question over the rail-to-rail operation.