minimum time for IO pin to damage

execuse me, but what is the difference between my IC and the one you sent??

is speed the only difference between them??

In our application we are not interested in speed we donot transfer data on these IO lines we just read the values on the 128 points periodically and these 128 points are exposed to the hand of the user of this card so they are exposed to +/- electrostatic charges, Iasked before here in the forum about an IC which delete the effect of the ESD and they adviced me with an IC like the one you sent, but I choosed that one because it removes esd up to +/-30 KV but the problem here is in the negative side the IO pin of FPGA is exposed to a voltage equal to -4 volt for a time not less than 200 nano second, so we think it may damage..

I hope this explaination will help..