JAJSFU8D November 2017 – June 2024 ADS8166 , ADS8167 , ADS8168
PRODUCTION DATA
To use the maximum dynamic range of the ADC, bias the input signal around the mid-scale of the ADC input range. In the ADS816x, where the absolute input range is 0V to the reference voltage (VREF), mid-scale is VREF / 2. The REFby2 buffer generates the VREF / 2 signal for mid-scale shifting of the input signal. Figure 6-8 shows REFBy2 used in various types of sensor signal conditioning circuits.
A resistor divider at the output of the reference buffer, as shown in Figure 6-9, generates the VREF / 2 signal. When not using the internal reference buffer (see the PD_CNTL register), any voltage applied at the REFP pin is applied to the resistor divider. The output of the resistor divider is buffered and available at the REFby2 pin.
The REFby2 buffer is capable of sourcing up to 2mA of DC current. The REFby2 pin has ESD diode connections to AVDD and GND.