In a DRAM memory circuit, a current sensing amplifier is provided that exploits the low impedance of a reference transistor biased in the sub-threshold regime to enable transfer of a small voltage swing on the bitline to result in a large voltage signal on a low capacitance sense node. Compared to conventional voltage sensing, reduced bitline-bitline coupling noise results because of the small bitline swing, potentially allowing more cells to be served by a sense amplifier because of weak dependence of sense amplifier on bit-line capacitance. Compared to previous current-sensing schemes, this invention allows no idling current. The current-sensing amplifier additionally may be used in conjunction with a hierarchical bitline scheme to further increase the number of cells served by each sense amplifier.