Compact low-voltage rail-to-rail bulk-driven CMOS opamp for scaled technologies

This paper illustrates the rail-to-rail capability of a single-pair bulk-driven CMOS input stage operated from an extremely low supply voltage. A composite input stage is also introduced for performance comparison, based on experimental data obtained in standard 0.35 mum CMOS technology with a supply voltage of 1 V. Measurements demonstrate the rail-to-rail suitability of the single-pair input stage and show advantages of this approach in some amplifier performance, such as linearity and common-mode rejection ratio, as compared to the case of the composite solution. The performance achieved can be extended to a nanoscale process, as lower supply voltages in scaled technologies are expected.