It will be appreciated to those skilled in the art having the benefit of this disclosure that this disclosure is believed to provide various embodiments of improved CMOS input stage circuits and related methods to maintain a near constant transconductance (g_m) across the entire common mode voltage (CMV) range, including within a near voltage region surrounding a cross-over voltage (V_cross) boundary between a low CMV region and a high CMV region of the CMV range. Further modifications and alternative embodiments of various aspects of the disclosure will be apparent to those skilled in the art in view of this description. For example, although the input stage circuits disclosed herein are implemented using CMOS technology, the disclosed input stage circuits could be alternatively implemented using other types of field effect transistors (FETs) or bipolar junction transistors (BJTs).

It is to be understood that the various embodiments of the disclosed CMOS input stage circuits shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the disclosed embodiments may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this disclosure. It is intended, therefore, that the following claims be interpreted to embrace all such modifications and changes and, accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.