METHOD AND APPARATUS FOR MRAM SENSE REFERENCE TRIMMING

摘要

A trimming process for setting a reference current used in operating an MRAM module comprising an operational MRAM cell coupled to a bit line, multiple reference MRAM cells coupled to a reference bit line, and a sense amplifier coupled to the bit line and the reference bit line is disclosed in some embodiments. The process includes applying a bit line reference voltage to the reference bit line to provide a reference cell current formed by a sum of respective currents through the plurality of reference MRAM cells. The reference cell current is detected. A determination is made as to whether the detected reference cell current differs from a target reference cell current. The bit line reference voltage is varied, or a sensing ratio of the sense amplifier is varied, if it is determined that the detected reference cell current differs from the target reference cell current.

主权项

1. A trimming method for setting a reference current used in operating a magneto-resistive random access memory (MRAM) module comprising a first MRAM cell coupled to a bit line, a plurality of reference MRAM cells coupled to a reference bit line, and a sense amplifier coupled to the bit line and the reference bit line, the method comprising:
applying a bit line reference voltage to the reference bit line to provide a reference cell current formed by a sum of respective currents through the plurality of reference MRAM cells; detecting the reference cell current; determining whether the detected reference cell current differs from a target reference cell current; and varying one of the bit line reference voltage and a sensing ratio of the sense amplifier if it is determined that the detected reference cell current differs from the target reference cell current.