The invention claimed is:1. An incremental delta-sigma analog-to-digital converter (ADC), comprising:a sample-and-hold circuit comprising a first switch, a second switch, a first capacitor, and an amplifier; andan integrator comprising the first capacitor, a second capacitor, and the amplifier;wherein the sample-and-hold circuit and the integrator share the first capacitor and the amplifier.2. The incremental delta-sigma ADC according to claim 1, further comprising a digital-to-analog converter connected to the integrator.3. The incremental delta-sigma ADC according to claim 1, wherein the first capacitor is directly connected between the first switch and an input terminal of the amplifier.4. The incremental delta-sigma ADC according to claim 1, wherein the second switch is directly connected to the first capacitor and an output terminal of the amplifier.5. The incremental delta-sigma ADC according to claim 1, wherein the second capacitor is directly connected between the first switch and an output terminal of the amplifier.6. The incremental delta-sigma ADC according to claim 1, wherein the integrator further comprises a resistor:directly connected in series with the first capacitor anddirectly connected to the first switch.7. The incremental delta-sigma ADC according to claim 1, wherein the first switch is connected in series with the second capacitor.8. The incremental delta-sigma ADC according to claim 1, wherein the first capacitor is connected in series with the amplifier.9. The incremental delta-sigma ADC according to claim 1, wherein the second switch is connected in parallel with the amplifier.10. A method for operating on an input signal with a delta-sigma analog-to-digital converter (ADC), wherein the input signal has a voltage, comprising:sampling the input signal comprising closing a first switch and a second switch;charging a first capacitor to the voltage of the input signal;holding the charge of the first capacitor comprising:opening the first switch and second switch; andapplying a high impedance to the first capacitor using an amplifier; andsumming an output voltage from a signal converter and the voltage of the first capacitor;integrating the summed voltage using a second capacitor in parallel with the amplifier.11. The method according to claim 10, wherein the first capacitor is connected directly between the first switch and an input terminal of the amplifier.12. The method according to claim 10, wherein the second switch is connected in parallel with the amplifier.13. The method according to claim 10, wherein the first switch is connected in series with the second capacitor.14. A system configured to receive an input signal having a voltage, comprising:a sample-and-hold circuit comprising a first switch, a second switch, a first capacitor, and an amplifier, and configured to:receive the input signal;sample the input signal comprising operating the first switch and the second switch;charge the first capacitor to the voltage of the input signal;hold the charge of the first capacitor comprising:operating the first switch and second switch; andapplying a high impedance to the first capacitor using the amplifier; anda first integrator comprising the first capacitor, a second capacitor, and the amplifier, and configured to integrate a summed voltage using the second capacitor and the amplifier, wherein the summed voltage is a sum of an output voltage of a digital-to-analog converter and the voltage of the first capacitor;wherein the sample-and-hold circuit and the first integrator share the first capacitor and the amplifier.15. The system according to claim 14, wherein the first capacitor is directly connected between the first switch and an input terminal of the amplifier.16. The system according to claim 14, wherein the second switch is:directly connected to the first capacitor and an output terminal of the amplifier; and is connected in parallel with the amplifier.17. The system according to claim 14, wherein the first switch is connected in series with the second capacitor.18. The system according to claim 14, wherein the second capacitor is directly connected between the first switch and an output terminal of the amplifier.19. The system according to claim 14, wherein the amplifier comprises a p-channel transistor connected in series with an n-channel transistor.20. The system according to claim 14, further comprising a second integrator connected to an output terminal of the first integrator.