a second switch that is provided between {HEAD ~ the second constant current source} and the first bit line, {TAIL ~ the second switch} being formed by a MONOS type transistor 
a second switch that is provided between { HEAD ~ the second constant current source } and the first bit line , { TAIL ~ the second switch } being formed by a MONOS type transistor
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH