Memory device with propagation circuitry in each sub-array and method thereof

Abstract

A memory device and method of operating such a device are provided. The memory device has a plurality of sub-arrays arranged to form at least one sub-array column having a first end and a second end, with each sub-array comprising a plurality of memory cells arranged in a plurality of memory cell rows and at least one memory cell column. Sub-array access circuitry is associated with each sub-array, for detecting read data from a selected memory cell column of the associated sub-array during a read operation, and global access circuitry then interfaces with the first end of the sub-array column. Each sub-array access circuitry comprises propagation circuitry for producing an output read data value, the propagation circuitry having a first input for receiving the read data detected from the associated sub-array during a read operation and a second input for receiving an output read data value produced by a linked sub-array access circuitry associated with a sub-array nearer the second end of the sub-array column. The propagation circuitry receives a control signal for identifying which of its first or second inputs should be used to produce the output read data value. As a result, an output read data value produced by any sub-array access circuitry is propagated to the global access circuitry via any linked sub-array access circuitry in the sub-array column between that sub-array access circuitry and the global access circuitry. This provides a particularly simple technique for propagating the read data value to the global access circuitry, which has both predictable timing, and consumes low power.