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