Single bitline direct sensing architecture for high speed memory device

Abstract

A single bitline direct sensing architecture employs a 4 transistor sense amplifier circuit located in each memory array, wherein the transistors function to selectively transfer data bits from either a true bitline or a complement bitline of the bitline pair to a data line. The data line is preferably arranged over a plurality of memory arrays. The data line may or may not be shared for the read and write operations. One current source is additionally used to precharge the datalines in a read mode, performing the function of a digital sensing scheme by detecting a resistance ratio between the current source and the transistor driven by the bitline for the corresponding array. A simple inverter may be used for detecting a level of the data line determined by the resistance ratio. The bitline pair is sensed in a single ended fashion, eliminating the need for a cross-coupled pair of CMOS devices, and thus reducing the required layout area. By accessing the bitline pair individually, two sets of control signals for the pre-charge, EQ EQ are developed to allow for bitline shielding in the array.