An analog-to-digital converter including a voltage generation unit and a plurality of sub ADCs, each including a selection unit for selecting a voltage generated by the voltage generation unit based on a number and forwarding the selected voltage to a comparator arrangement. The selection unit includes first and second switch layers. The first switch layer includes a plurality of switch groups, each including a plurality of switch devices, each connected to a unique output terminal of the voltage generation unit with a first terminal and to a common node of the switch group with a second terminal. The second switch layer includes a switch device between the common node of each switch group and the first output terminal of the selection unit and a switch device between the common node and the second output terminal of the selection unit. A control unit generates control signals for the switch devices.