Magnetic field sensor with permanent magnet biasing

A magnetic field sensor for sensing an external magnetic field along a sensing direction oriented perpendicular to a plane of the magnetic field sensor comprises a sensor bridge. The sensor bridge has a first sensor leg that includes a first magnetoresistive sense element and a second sensor leg that includes a second magnetoresistive sense element. The first and second sense elements include respective first and second pinned layers having corresponding first and second reference magnetizations within the plane and oriented in the same direction. The first and second sense elements further include respective first and second sense layers, each having an indeterminate magnetization state. A permanent magnet layer is proximate the magnetoresistive sense elements. In the absence of an external magnetic field, the permanent magnet layer magnetically biases the indeterminate magnetization state of each sense layer to produce a sense magnetization of the first and second sense layers.