During an ESD event, {HEAD ~ the zener diode} incurs {TAIL ~ breakdown} to lower the trigger voltage of the lateral SCR device to within a range of about 5 7 Volts to thereby discharge the ESD current prior to damage of an internal circuit being protected 
incurs
During an ESD event , { HEAD ~ the zener diode } incurs { TAIL ~ breakdown } to lower the trigger voltage of the lateral SCR device to within a range of about 5 7 Volts to thereby discharge the ESD current prior to damage of an internal circuit being protected
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH