SN74LVC244A: the abs. minimum input negative AC voltage

Part Number:SN74LVC244A

Hi, team,

I have one question about SN74LVC244A. What is the abs. minimum input negative AC voltage for this device?

In datasheet, only -0.5VDC is marked, and note (2) is described. From customer's test, the minimum input voltage is -1.152V/240ns.

So how to evaluate the risk to device pin?

And what is the recommended time when input pin voltage is <-0.5V? Could you supply to me the judgement method?

Thanks.

Johnny