The OPA167x devices are unity-gain stable, dual-channel and quad-channel op amps with low noise and distortion. Section 7.2 shows a simplified schematic of the OPA167x (one channel shown). These devices consist of a low-noise input stage with a folded cascode and a rail-to-rail output stage. This topology exhibits excellent noise and distortion performance across a wide range of supply voltages that are not delivered by legacy, commodity, audio operational amplifiers.