Low power carbon nanotube memory is realized such that a first dynamic circuit serves as a local sense amp for reading a memory cell through a lightly loaded local bit line, a second dynamic circuit serves as a segment sense amp for reading the local sense amp, a first tri-state inverter serves as an inverting amplifier of a global sense amp, and a second tri-state inverter serves as a bypass circuit for bypassing output from previous memory block. When reading, a voltage difference in the local bit line is converted to a time difference for differentiating high data and low data by the sense amps for realizing low power with dynamic operation. In particular, amplify transistor of the sense amps is composed of relatively long channel transistor for reducing turn-off current. And buffered data path is used for achieving fast data transfer. Additionally, alternative circuits and memory cell structures are described.