a comparison apparatus, coupled to the output driver, that generates {HEAD ~ a comparison output signal} according to a reference voltage and {TAIL ~ the differential signal}; and 
according to
a comparison apparatus , coupled to the output driver , that generates { HEAD ~ a comparison output signal } according to a reference voltage and { TAIL ~ the differential signal } ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH