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