In addition to providing near constant gm across the entire common mode voltage range and limiting phase margin degradation in the Vcross boundary region, one skilled in the art would understand how the CMOS input stage 500 shown in FIGS. 5 and 6 could be used to provide additional advantages. For example, if CMOS input stage 500 is used to maintain a near constant gm1 across the entire common-mode input voltage range and minimize phase margin degradation in the first stage of a two-stage operational amplifier (such as amplifier 300 of FIG. 3 (Prior Art)), the transconductance (gm2) of the second stage can be reduced. Since most of the amplifier power is consumed in the second stage, the total power consumed by the operational amplifier can be significantly reduced by using CMOS input stage 500 to minimize phase margin degradation in the first stage and configuring the second stage with a minimum required amount of transconductance (gm2). This enables a less complex architecture to be used in the second stage of the operational amplifier.
