I have recently been having issues where the buffer of the circuit below has been damaged. The output pin (2) does not change with changes to the input pin (1). I sent 2 of these ICs to Fairchild for FA analysis, and their report indicates that there was an Electrical Overstress (EOS) condition at the ESD circuitry of pin 1 which caused metallization.
Could this be due to too much current going into pin 1? I have checked the circuit many times, and do not see anyway for the input pin to be damaged.