The LV family incorporates internal ESD protection circuits on all pins. The inputs, and the open-drain output, use a proprietary "snapback" type ESD clamp from each pin to GND, which allows the pins to exceed the supply voltage (V+). While shown as Zener diodes, snapbacks momentarily "short" and go low impedance (like an SCR) when the threshold is exceeded, as opposed to clamping to a defined voltage like a Zener. There is no ESD clamp from the inputs to V+.
The open-drain output protection also consists of a ESD clamp between the output and GND to allow the output to be pulled above V+ to a maximum of 5.5V. There is no ESD clamp from the output to V+.
If the inputs are to be connected to a low impedance source, such as a power supply or buffered reference line, TI recommends adding a current-limiting resistor in series with the input to limit any transient currents should the clamps conduct. The current should be limited 10 mA or less. This series resistance can be part of any resistive input dividers or networks.
TI does not specify the performance of the ESD clamps and external clamping diodes should be added if the inputs or output could exceed the maximum ratings as part of normal operation.