Patent ID: 7499314

Claim:
An MRAM reference cell sub-array programming apparatus comprising: a fixture for retaining a substrate onto which a substrate comprising a plurality of MRAM reference cell sub-arrays in communication with a plurality of sense amplifiers formed on said substrate, said plurality of MRAM reference cell sub-arrays comprising: a plurality of MRAM cells arranged in rows and columns; a plurality of bit lines, each bit line associated with a free magnetic layer of each MRAM cell of a column of the plurality of MRAM cells, and a coupling to connect the bit lines of pairs of the columns of the plurality of MRAM cells together; a control apparatus in communication with said plurality of MRAM reference cell sub-arrays for isolating said plurality of MRAM reference cell sub-arrays from said plurality of sense amplifiers; a magnetic field generation device placed in near proximity to generate a magnetic field having an orientation to a desired magnetic orientation of said plurality MRAM cells; and a free layer programming device for conveying a free layer programming current in a first direction on each bit lines of the first column of the pairs of columns of MRAM cells to be transferred through said coupling to each bit line of the second column of the pairs of columns of MRAM cells; wherein a pair of the MRAM cells of said pair of columns are on a common row of said MRAM cells and a first of said pair of MRAM cells is programmed to a first magneto-resistive state and a second of said pair of MRAM cells is programmed to a second magneto-resistive state such that when one row of MRAM cells are selected for read, said pair of MRAM cells are placed in parallel to generate said mid-point reference current.