The pump down circuit may be configured to generate a pump down {TAIL ~ signal} in response to the pump up signal and {HEAD ~ the control signal} 
The pump down circuit may be configured to generate a pump down { TAIL ~ signal } in response to the pump up signal and { HEAD ~ the control signal }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD