18.4 Behavior Under Low Supply Voltage Condition

After the battery voltage has been connected to the application circuit, the voltage at the LIN_V_DD pin increases according to the block capacitor used in the application (see Figure 18-1). If V_VS is higher than the minimum V_S operation threshold, V_{VS_th_U_F_up}, the IC mode changes from Unpowered mode to Fail-Safe mode, the LIN_INH output is switched on and the LIN transceiver can be activated.

If during Sleep mode, the voltage level of V_VS drops below the undervoltage detection threshold,V_{VS_th_N_F_down} (typically 4.3V), the Operation mode is not changed and no wake-up is possible. Only if the supply voltage on the LIN_V_DD pin drops below the VS operation threshold, V_{VS_th_U_F_down} (typically 2.05V), does the IC switch to Unpowered mode.

If, during Normal mode, the voltage level on the LIN_V_DD pin drops below the VS undervoltage detection threshold, V_{VS_th_N_F_down} (typically 4.3V), the IC switches to Fail-Safe mode. This means that the LIN transceiver is disabled in order to avoid malfunctions or false bus messages. If the supply voltage, V_VS, drops further below the V_S operation threshold, V_{VS_th_U_F_down} (typically 2.05V), the IC switches to Unpowered mode and the LIN_INH output switches off.