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-mu m 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 nanoscale process, as lower supply voltages in scaled technologies are expected.