The MUX36xxx have a simple transmission gate topology, as shown in Figure 39. Any mismatch in the stray capacitance associated with the NMOS and PMOS causes an output level change whenever the switch is opened or closed.
The MUX36xxx have special charge-injection cancellation circuitry that reduces the source-to-drain charge injection to as low as 0.3 pC at VS = 0 V, and ±0.6 pC in the full signal range, as shown in Figure 40.
The drain-to-source charge injection becomes important when the device is used as a demultiplexer (demux), where D becomes the input and Sx becomes the output. Figure 41 shows the drain-to-source charge injection across the full signal range.