An analog-to-digital converter (ADC) and a battery operated electronic device comprising the ADC. The ADC comprising an input switch; an array of binary-weighted capacitors, the array of capacitors receiving the input voltage signal via the input switch in an on state of the input switch; a plurality of switches, each switch connected in series with a respective one of the capacitors at an opposite side compared to the input switch, wherein a VDD signal is applied to each switch in one switching state and ground in another switching state; a comparator having as one input a voltage from the input switch side of the array of capacitors and as another input a voltage of VDD/2; and a switch control unit coupled to an output of the comparator for controlling the switches based on the output from the comparator.