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