A high bandwidth constant g/sub m/ and slew-rate rail-to-rail CMOS amplifier circuit for embedded low-voltage applications

A rail-to-rail CMOS amplifier input structure is presented which maintains near constant g/sub m/ and slew current for any common mode input level. Feedforward is used to achieve high bandwidth, and operation does not depend upon idealised MOS characteristics. The circuit may be used as the input for one or two stage op-amps, transconductors and asynchronous comparators. The near ideal behaviour at any input level means that accurate VHDL modelling is easily performed for large scale integrated system simulation.