An input stage for a switched capacitor analog-to-digital converter has a differential voltage input receiving an input voltage, a differential reference voltage input receiving a chopped reference voltage, a common voltage connection, and a differential output. A pair of input capacitors is coupled between the differential voltage input and the differential output and a pair of reference capacitors is coupled between the differential reference voltage input. A switching unit is controlled by a first and second phase operable during the first phase to connect a first terminal of the input capacitors with the common voltage connection and couple the first terminal of the reference capacitors with the inverted differential voltage reference; and during a second phase to connect the first terminal of the input capacitors with the differential input voltage and couple the first terminal of the reference capacitors with the non-inverted differential voltage reference.