A sample and integrate circuit includes first and second switching devices. A first terminal of the first switching device communicates with a first input voltage when the first switching device is in the second state. The first terminal of the first switching device communicates with a first voltage reference when the first switching device is in the first state. A first capacitance communicates with the second terminal of the first switching device. A first terminal of the second switching device communicates with a second input voltage when the second switching device is in the first state. The first terminal of the second switching device communicates with a second voltage reference when the second switching device is in the second state. A first input of an amplifier communicates with the first capacitance and a second capacitance. A second input of the amplifier communicates with a third capacitance and a fourth capacitance.