1.2 Attenuation (Voltage Divider with Buffered Stage)
The sensor output signal requires attenuation when its voltage range exceeds the input voltage range of the ADC. The resistive divider can easily attenuate any range of voltages, but it provides lower impedance to the source and higher impedance to the ADC. A unity-gain buffer provides high-input impedance (~MΩ) and very low-output impedance (< 10 KΩ) necessary for the ADC of microcontrollers. The applications such as temperature sensing and battery voltage monitoring require a sensor output signal attenuation to keep the signal within the allowed input signal range of the ADC.