SCDS394A March 2021 – October 2021 TMUX7462F
The TMUX7462F is not intended for standalone electromagnetic compatibility (EMC) protection in industrial applications. There are three common high voltage transient specifications that govern industrial high voltage transient specifications: IEC61000-4-2 (ESD), IEC61000-4-4 (EFT), and IEC61000-4-5 (surge immunity). A transient voltage suppressor (TVS), along with some low-value series current limiting resistor, are required to prevent source input voltages from going above the rated ±60 V limits.
It is critical to ensure that the maximum working voltage is greater than the normal operating range of the input source pins protected and any known system common-mode overvoltage that may be present due to incorrect wiring, loss of power, or short circuit when selecting a TVS protection device. Figure 8-2 shows an example of the proper design window when selecting a TVS device.
Region 1 denotes the normal operation region of TMUX7462F, where the input source voltages stay below the fault supplies VFP and VFN. Region 2 represents the range of possible persistent DC (or long duration AC overvoltage fault) presented on the source input pins. Region 3 represents the margin between any known DC overvoltage level and the absolute maximum rating of the TMUX7462F. The TVS breakdown voltage must be selected to be less than the absolute maximum rating of the TMUX7462F, but greater than any known possible persistent DC or long duration AC overvoltage fault to avoid triggering the TVS inadvertently. Region 4 represents the margin the system designers must impose when selecting the TVS protection device to prevent accidental triggering the ESD cells of the TMUX7462F.