The operational amplifier also includes source transistors for pushing the output and sink transistors for pulling {HEAD ~ the output} to obtain {TAIL ~ particular output voltage swing} 
The operational amplifier also includes source transistors for pushing the output and sink transistors for pulling { HEAD ~ the output } to obtain { TAIL ~ particular output voltage swing }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL