CD4066B has four independent digitally controlled analog switches with a bias voltage of V_SS to allow for different voltage levels to be used for low output. Both the p and n devices in a given switch are biased on or off simultaneously by the control signal. As shown in Figure 7-1, the well of the n-channel device on each switch is tied to either the input (when the switch is on) or to V_SS (when the switch is off). Thus, when the control of the device is low, the output of the switch goes to V_SS and when the control is high the output of the device goes to V_DD.