Temperature stability of a CMOS operational amplifier

A theoretical study of the different parameters of a CMOS operational amplifier is presented in order to minimize the temperature drift of the system. By choosing the proper bias of the different MOSFET transistors to operate at zero temperature coefficient, the drift has been reduced significantly. A typical MOSFET operational amplifier consisting of a differential stage, differential input to single output converter, and common source output stage has been used for the study. A current-source circuit has been designed in order to provide the proper bias for the system devices. Expressions for the bias voltages and drain currents for operation at zero temperature coefficient were derived. The offset and frequency response of the system under the given bias were determined.<>