In one embodiment, an apparatus comprises a first capacitor system and a second capacitor system. Each capacitor system is removably coupled to the same portion of an analog to digital converter (ADC) and the same sensing circuit. Each capacitor system stores charge received through the sensing circuit when coupled to the sensing circuit and provides the charge received through the sensing circuit to the ADC for conversion into a digital value when coupled to the ADC. When the control signals are in a first state, the first capacitor system receives charge through the sensing circuit and the second capacitor system is coupled to the portion of the ADC. When the one or more control signals are in a second state, the second capacitor system is coupled to the sensing circuit to receive charge through the sensing circuit and the first capacitor system is coupled to the portion of the ADC.