There are three under-voltage events monitored in the TCAN146x-Q1, V_SUP, V_IO and V_CC. The three supply terminals are input sources for the TCAN146x-Q1 and have under-voltage detection circuitry which places the device in a protected state if an under-voltage fault occurs, UV_SUP, UV_CC and UV_IO. This protects the bus during an under-voltage event on these terminals. If V_SUP experiences an under-voltage event, the device loses the source needed to keep the internal regulators active. This causes the device to go into a state where communication between the microprocessor and the TCAN146x-Q1 is disabled. The TCAN146x-Q1 is not able to receive information from the bus; and thus, does not pass any signals from the bus, including any Bus Wake via BWRR signals to the microprocessor. See Table 8-9. For under-voltage events, there is a filter time, t_UVFLTR, that the even must last longer than for the t_UVSLP timer to start. Once the t_UVSLP timer expires and the under-voltage condition is still present, the device enters sleep mode or fail-safe mode if enabled.