Magnetoresistive signal isolators employing linear spin-valve sensing resistors

Abstract

Feasibility of fabricating low power, high-speed, magnetoresistive signal isolators employing linear spin-valve resistors as sensing elements has been demonstrated. In the fabricated prototype digital isolators, linear spin-valve resistors are physically isolated from an on-chip coil by an 11 μm BCB isolation barrier, which provides the galvanic isolation with a breakdown voltage larger than 2000 V. The devices are high speed (>50 MHz), small size, and low power consumption. Only a 4.5 mA coil driving current is required for the device to be fully functional. The power consumption is estimated to be ∼1/6 of NVE’s present isolator products, which requires a 50 mA coil driving current. Besides digital signal isolators, linear spin-valve resistors can also be used in analog signal isolators. The response of the linear spin-valve resistors to the current passing through the coil has been demonstrated to have a very good linearity, with a linearity error less than 0.05%.