ADC with low-power sampling

An apparatus for analog-to-digital conversion using successive approximation is provided, which is adapted to be supplied with a single ended supply voltage. The device includes: a first analog-to-digital conversion stage including a first set of capacitors coupled with a side at a common node and adapted to sample an input voltage and to be coupled to either a first reference voltage level or a second reference voltage level, at least one capacitor of the first set of capacitors being adapted to be left floating, a control stage being adapted to connect the at least one floating capacitor to the first reference voltage level or the second reference voltage level in response to an analog-to-digital conversion decision made by a second analog-to-digital conversion stage. The first analog-to-digital conversion stage is operable to couple the common node to a supply voltage level, in particular ground, during analog-to-digital conversion.