The SHDN pin is only applicable to TCAN3404-Q1 and is used to put the device in ultra-low power mode. SHDN pin has an internal pull-down resistor on-chip, so if the pin is left floating, the device is in normal mode or standby mode depending on the state of STB pin. Pulling SHDN pin high externally puts the device in shutdown. All blocks (including low power wakeup receiver) are disabled in this mode. SHDN pin has higher priority compared to STB pin.