A Fully Integrated Analog Compensation for the Piezo-Hall Effect in a CMOS Single-Chip Hall Sensor Microsystem

A magnetic sensor microsystem with Hall plates, temperature sensor, and stress sensor designed for the purpose of temperature-dependent piezo-Hall effect compensation has been implemented in 0.35μm CMOS technology. The sensor microsystem as well as the compensation method is entirely realized in integrated analog circuitry. A dedicated stress sensor delivers a signal proportional to the sum of in-plane normal stresses. At the systems level, the analog circuit compensates the stress-related drift of the magnetic sensitivity by adding a current proportional to the stress sensor signal on top of the Hall plate supply current. After a three-temperature calibration of a sensor molded in a SOIC-8 package extending from -40 °C to +125 °C, the residual thermal drift of the magnetic sensitivity was reduced to <;0.5%. The stress-related drift due to a humidity change from humid to dry was reduced to <;0.6% for samples packaged in SOIC-8 and single-in-line molded packages.