SBAS572B May 2013 – March 2019 ADS8864
As shown in Figure 44, the device features a single-ended analog input. AINP can swing from GND – 0.1 V to VREF + 0.1 V and AINN can swing from GND – 0.1 V to GND + 0.1 V. Both positive and negative inputs are individually sampled on 55-pF sampling capacitors and the device converts for the voltage difference between the two sampled values: VINP – VINN. The single-ended signal range is 0 V to VREF.
Figure 45 shows an equivalent circuit of the input sampling stage. The sampling switch is represented by a 96-Ω resistance in series with the ideal switch; see the ADC Input Driver section for more details on the recommended driving circuits.
Figure 44 and Figure 45 illustrate electrostatic discharge (ESD) protection diodes to REF and GND from both analog inputs. Make sure that these diodes do not turn on by keeping the analog inputs within the specified range.