A redundant reference layout circuit for magnetic random access memory

Abstract

The invention discloses a redundant reference layout circuit for a magnetic random access memory, which is used for reading a data memory unit of the magnetic random access memory and comprises a reference unit, a current mirror, a control current limiting circuit, a reference selection switch and a comparator, and the reference selection switch selects a reference column in the reference unit, carries out reference average processing through the current mirror to obtain an average potential VP and a magnetic tunnel junction potential VMTJ to be tested of the memory unit, sends the average potential VP and the magnetic tunnel junction potential VMTJ to the comparator for comparison, and reads data in the data memory unit. According to the invention, the problem that a large number of datamemory units taking the bad reference magnetic tunnel junctions as the reference cannot be accurately read due to the existence of the bad reference magnetic tunnel junctions is improved, and the badreference magnetic tunnel junctions are excluded from the final reference, so that the data reading accuracy is improved.

Description

technical field [0001] The invention belongs to a method for reading and writing data of a memory in the field of semiconductor chip memory, in particular to a redundant reference layout circuit for a magnetic random access memory. Background technique [0002] Magnetic Random Access Memory (MRAM) is an emerging non-volatile storage technology. It has high-speed read and write speed and high integration, and can be rewritten infinitely. [0003] An MRAM is composed of an array of magnetoresistive memory cells. Each magnetoresistive memory cell contains a structure called a magnetic tunnel junction (MTJ). A magnetic tunnel junction consists of two layers of ferromagnetic material sandwiching a very thin layer of non-ferromagnetic insulating material. One layer of ferromagnetic material is a reference layer with a fixed magnetization direction, and the other layer of ferromagnetic material is a memory layer with a variable magnetization direction, and its magnetization dire...

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Problems solved by technology

[0007] In view of the above-mentioned defects of the prior art, the object of the present invention is to provide a redundant reference layout circuit for magnetic random access memory, using a new reference resistor arrangement and data reading method, using redundant reference columns to eliminate this defect The influence of the reference magnetic tunnel junction has improved the problem that a large number of data memory cells that use this as a reference cannot be accurately read due to the existence of individual bad reference magnetic tunnel junctions

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