[FAQ] Can a digital signal be applied to digital isolator input when its respective VCC is 0V?

The absolute maximum rating of most digital isolator input pins is "V_CCx + 0.5V" as shown in the screenshot below from a digital isolator datasheet. This means that when V_CCx = 0V, the maximum voltage that can be applied to input pin should be <0.5V. Therefore, applying a valid logic voltage (like 3.3V or 5V) to input pin when its respective VCC is 0V violates the absolute maximum rating and possibly cause permanent damage to device. Hence, it is not recommended to apply a digital signal to input of a digital isolator when its respective VCC is 0V.