The ISOW1044 device has multiple protection features to create a robust system level solution.

• The first feature is an Enable/Fault protection feature. This EN/FLT pin can be used as either an input pin to enable or disable the integrated DC-DC power converter or as an output pin which works as an alert signal if the power converter is not operating properly. In the /Fault use case, a fault is reported if V_DD > 7 V, V_DD < 2.5 V, or if the junction temperature >170°C. When a fault is detected, this pin will go low, disabling the DC-DC converter to prevent any damage.

  Figure 10-7 EN Fault Pin Diagram

• An over-voltage clamp feature is present on V_ISOOUT which will clamp the voltage at 6 V if there is an increase in voltage seen. For device reliability, it is recommended that V_ISOOUT stays lower than the over-clamp voltage for device reliability.

• Over-Voltage Lock Out (OVLO) on V_DD will occur when a voltage higher than 7 V on V_DD is seen. At OVLO, the device will go into a low power state and the EN/FLT pin will go low.

• In cases of overload or short on power converter output V_ISOOUT, maximum duty cycle of power converter is limited. In cases of driver bus short circuit due to the external power supply cable shorting to the bus cable, short circuit current protection on CAN chip restricts the bus current to ±115 mA maximum.

• Thermal protection is also integrated to help prevent the device from getting damaged under such scenarios. An increase in the die temperature is monitored and the device is disabled when the die temperature becomes 165 ℃ (typical), thus disabling the short condition. The device is re-enabled when the junction temperature becomes 155 ℃ (typical). If an overload or output short-circuit condition prevails, this protection cycle is repeated. Care should be taken in the system design to prevent repeated or prolonged exposure to bus shorts as this exposes the device to high junction temperatures for extreme amounts of time affecting device reliability.