Patent ID: 9116199
Filing Date: 2015-08-25
Classification: B82Y,G01B,G01D,G01R,H01L

Abstract:
1. A single-package magnetoresistive rotation sensor, comprising: a pair of MTJ or GMR magnetoresistive sensor chips, wherein one of the MTJ or GMR magnetoresistive sensor chips in the pair is rotated 180 degrees with respect to the other, and the MTJ or GMR magnetoresistive sensor chips are adhered to a semiconductor package lead frame and configured as a single-axis push-pull full-bridge rotation sensor; each of the MTJ or GMR magnetoresistive sensor chips is configured as a pair of magnetoresistive elements, where each of the magnetoresistive elements in the pair comprises a string of one or more GMR or MTJ magnetoresistive sensor elements; the GMR or MTJ magnetoresistive sensor elements are configured as a spin-valve comprised of a free magnetic layer and a pinned magnetic layer, where the direction of the pinned magnetic layer is free to rotate relative to the magnetic easy-axis of the GMR or MTJ magnetoresistive sensor element, and the intrinsic saturation field of the free magnetic layer is at least a factor of 10 less than the pinning field of the pinned magnetic layer; the free magnetic layer includes no magnetic biasing in the direction perpendicular to the direction of the pinned magnetic layer magnetization, such that the free magnetic layer magnetization rotates proportionally to the direction of an applied magnetic field; the intrinsic saturation field of each GMR or MTJ magnetoresistive sensor element minus the offset magnetic field of the GMR or MTJ magnetoresistive sensor chip's transfer curve is less than magnetic field the sensor bridge is intended to measure; bond pads of each GMR or MTJ magnetoresistive sensor chip are designed such that more than one wire bond is attached to each side of each string of GMR or MTJ magnetoresistive sensor elements; each GMR or MTJ magnetoresistive sensor chip has a crossover in top and bottom conductors, such that the bond pads on one side of the GMR or MTJ magnetoresistive sensor chip can be swapped in position with respect to the magnetoresistive elements, in order to permit wirebonding of the two identical GMR or MTJ magnetoresistive sensor chips to form the single-axis push-pull full-bridge rotation sensor without crossing the corresponding bond wires; the oppositely oriented GMR or MTJ magnetoresistive sensor chips have similar R the input and output connections of the MTJ or GMR magnetoresistive sensor chips are wire bonded to the semiconductor package lead frame.