TIDA-00187, Extending Rail-to-Rail Output Range for Fully Differential Amplifiers to Include True Zero Volts

TIDA-00187, Operational amplifiers (Op-Amps) have been used for decades in signal conditioning circuits and measurement systems. An Op-Amp that has an output spanning from negative to positive supply rail are generally referred to as rail-to-rail output (RRO) Op-Amps. These devices have been used increasingly in portable systems to drive analog to digital converters (ADCs) where reducing power consumption while not sacrificing converter dynamic range is a key concern. While the task calls for the lowest power RRO Op-Amps, circuit designers are finding out that rail-to-rail doesn't exactly mean rail-to-rail. In reality the output is limited to a couple hundred millivolts within the rail depending on the loading