Figure 30 shows the small-signal equivalent circuit of the sample-and-hold circuit. Each sampling switch is represented by resistance (RS1 and RS2, typically 50 Ω) in series with an ideal switch (SW). The sampling capacitors, CS1 and CS2, are typically 60 pF.
The multiplexer on-resistance (RMUX), is typically a 40-Ω resistor in series between the ON channel and the MUXOUT-P or MUXOUT-M pins. The multiplexer analog input typically has a 13-pF on-channel capacitance (CMUX).
During the input signal acquisition phase, the ADC-INP and ADC-INM inputs are individually sampled on CS1 and CS2, respectively. During the conversion process, the device converts for the voltage difference between the two sampled values: VADC-INP – VADC-INM.
Each analog input pin has electrostatic discharge (ESD) protection diodes to AVDD and GND. Keep the analog inputs within the specified range to avoid turning the diodes on.