A method of operating an amplifier circuit having a pre-charge phase and a sample/conversion phase includes, during a pre-charge phase, charging first and second capacitors to first and second bias voltages. The first capacitor is coupled to a first input of an amplifier circuit, which has a second input and an output. The second capacitor is coupled to the second input. During a sample/conversion phase, the first input of the amplifier circuit is coupled to an input signal through the first capacitor to level-shift the input signal according to the first bias voltage and the output of the amplifier is coupled to the second input through the second capacitor to level shift a feedback signal according to the second bias voltage.