If the voltage on any source pin goes above the supplies (V_DD or V_SS) by one threshold voltage (V_T), the overvoltage protection feature of the TMUX7308F and TMUX7309F is triggered to turn off the switch under fault, keeping the fault channel in a high-impedance state. I_S(FA) and I_D(FA) denotes the input and output leakage current under overvoltage fault conditions, respectively. For I_D(FA) the device is disabled to measure leakage current on the drain pin without being impacted by the 40 kΩ impedance to the fault supply. When the overvoltage fault occurs, the supply (or supplies) can either be in normal operating condition (Figure 8-4) or abnormal operating condition (Figure 8-5). During abnormal operating condition, the supply (or supplies) can either be unpowered (V_DD= V_SS = 0 V) or floating (V_DD= V_SS = no connection), and remains within the leakage performance specifications.

Figure 8-4 Measurement Setup for Input and Output Leakage Current under Overvoltage Fault with Normal Supplies

Figure 8-5 Measurement Setup for Input and Output Leakage Current under Overvoltage Fault with Unpowered or Floating Supplies