The ADC122S655 is a dual 12-bit, 200 kSPS to 500 kSPS simultaneous sampling Analog-to-Digital (A/D) converter. The analog inputs on both channels are sampled simultaneously to preserve their relative phase information to each other. The converter is based on a successive-approximation register architecture where the differential nature of the analog inputs is maintained from the internal track-and-hold circuits throughout the A/D converter to provide excellent common-mode signal rejection. The ADC122S655 features an external reference that can be varied from 1.0V to VA.