The ADC121S625 is a 12-bit, 50 ksps to 200 ksps sampling Analog-to-Digital (A/D) converter that features a fully differential, high impedance analog input and an external reference. While best performance is achieved with reference voltage between 500mV and 2.5V, the reference voltage can be varied from 100mV to 2.5V, with a corresponding resolution between 49μV and 1.22mV.