Methods for detecting damage to magnetoresistive sensors

摘要

A system and method for detecting a damaged magnetoresistive sensor includes measuring a median DiffPN value of a group of GMR sensors on a module, the sensors characterized as having been deposited on a same wafer and having been lapped as a single unit; comparing the DiffPN values to the median; determining that physical and/or magnetic damage has occurred to an individual sensor if the difference in the DiffPN value of the individual sensor from the median is greater than a statistically predetermined value for the group of sensors; where the difference is at least one times the average of the standard deviations of a large number of normal modules or the average of the standard deviations of a large number of modules, wherein at least the largest and the smallest DiffPN value within the module is not included in the calculation of the module's standard deviation.

主权项

1. A method for detecting a damaged magnetoresistive sensor, comprising:
measuring DiffPN values of a group of GMR sensors on a module; determining a median DiffPN value of the group of GMR sensors, the sensors characterized as having been deposited on a same wafer and having been lapped as a single unit; comparing the DiffPN values to the median DiffPN value; determining that at least one of physical and magnetic damage has occurred to an individual sensor if the difference in the DiffPN value of the individual sensor from the median is greater than a statistically predetermined value for the group of sensors; where the difference is at least one times an average of standard deviations of a number of normal modules or an average of standard deviations of a number of modules, wherein at least a largest and a smallest of the DiffPN values within the module are not included in the calculation of the module's standard deviation.