A CMOS single-ended OTA with high CMRR

A high CMRR single-ended current-mirror OTA employing a novel current CMFB is proposed. The OTA input/output common mode range, die area, power and slewing speed are not affected. The settling speed is reduced by 5%-20%. The current CMFB boosts the OTA CMRR by a factor of 30 while allowing integration of conventional OTA improvements. A unified approach relating the CMRR and transistor mismatches is proposed. The OTA was manufactured in a standard 0.25/spl mu/m CMOS process as a precision functional block of a 12 bit algorithmic ADC.