Auto-calibration technique for on-chip reference voltage generation in ferroelectric memories

This paper proposes a programmable reference voltage (V_REF ) generation scheme for ITIC ferroelectric random-access memories (FeRAM). A range of possible voltages are generated by charge sharing a fixed number of bitlines, which have been precharged to different voltages. An appropriate V_REF is selected for sensing after calibrating it across the memory cell array. The proposed technique provides programmability in the reference voltage with relatively little area overhead and with little extra sensing time. This flexibility can be used to track parameter variations over time. It is compact enough to allow different V_REF´s to be provided to multiple subarrays, hence possibly raising the cell yield