The output of {HEAD ~ the unity gain amplifier} is used to drive the parasitic NPN transistors and also is furnished as {TAIL ~ the reference voltage} 
The output of { HEAD ~ the unity gain amplifier } is used to drive the parasitic NPN transistors and also is furnished as { TAIL ~ the reference voltage }
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL