The OPA1655 and OPA1656 (OPA165x) use a three-gain-stage architecture to achieve very low noise and distortion. The Functional Block Diagram shows a simplified schematic of the OPA165x (one channel shown). The devices consist of a low-noise input stage and feedforward pathway coupled to a high-current output stage. This topology exhibits superior distortion performance under a wide range of loading conditions compared to other operational amplifiers.