A low-voltage fully differential constant signal behavior rail-to-rail input stage in 0.12μm CMOS

This paper introduces a new fully differential low- voltage rail-to-rail input structure, which possesses a constant large- and small-signal behavior over the entire input common- mode range, and is suitable for low supply voltage applications in deep-submicron technologies. The proposed input stage is fabricated with two different opamp architectures in pure digital 0.12mum CMOS technology for experimental verification. At plusmn0.5V supply, the _gm-variation is only 5.45%. The slew-rate+/- deviation is 3.5/3.2%. The maximum current for signal behavior regulation is reduced down to 90 mum.