The TMUX1109 supports Fail-Safe Logic on the control input pins (EN, A0, A1) allowing for operation up to 5.5V above V_SS, regardless of the state of the supply pin. This feature allows voltages on the control pins to be applied before the supply pin, protecting the device from potential damage. Fail-Safe Logic minimizes system complexity by removing the need for power supply sequencing on the logic control pins. For example, the Fail-Safe Logic feature allows the select pins of the TMUX1109 to be ramped to 5.5V while V_DD = 0V. Additionally, the feature enables operation of the TMUX1109 with V_DD = 1.2V while allowing the select pins to interface with a logic level of another device up to 5.5V.