Standby mode is entered either by a wake-up event through LIN bus while the device is in sleep mode or by the EN pin from normal or standby init modes. From normal mode EN must be low for > t_EN and TXD and nRST are high. RXD pin in standby mode is dependent upon how standby mode was entered. If entered from normal mode or power up, RXD is high. If entered from sleep mode, RXD is pulled low to indicate a wake event. When entering standby mode from normal or standby init modes, a wake event on the LIN bus causes the RXD pin to be pulled low.

During power up, if EN is low the device goes into standby mode, and if EN is high, the device goes into normal mode. EN has an internal pull-down resistor ensuring EN is pulled low if the pin is left floating in the system.