The LV family inputs are fault tolerant up to 5.5V independent of V+. Fault tolerant is defined as maintaining the same high input impedance when V+ is unpowered or within the recommended operating ranges.
The fault tolerant inputs can be any value between 0 V and 5.5 V, even while V+ is zero or ramping up or down. This feature avoids power sequencing issues as long as the input voltage range and supply voltage are within the specified ranges. This is possible since the inputs are not clamped to V+ and the input current maintains its value even when a higher voltage is applied to the inputs.
As long as one of the input pins remains within the valid input range, and the supply voltage is valid and not in POR, the output state will be correct.
The following is a summary of input voltage excursions and their outcomes:
Even with the fault tolerant feature, TI strongly recommends keeping the inputs within the specified input voltage range during normal system operation to maintain datasheet specifications. Operating outside the specified input range can cause changes in specifications such as propagation delay, which can lead to unpredictable behavior.