Low-cost epoxy packaging of CMOS Hall-effect compasses

For the first time, a compass using CMOS Hall-sensors in a low-cost epoxy package is presented. Due to the high mechanical stress sensitivity of CMOS Hall-sensors, such low-cost plastic or epoxy mold packages have not been a viable option for low-offset applications like the compass application. Instead, expensive ceramic packages have been used. A recently developed, stress insensitive, CMOS Hall-sensor, shows only a 1.65muT offset shift after epoxy molding, while maintaining its low 3muT (3a) offset spread. After repeated thermal shock, the Hall sensor´s offset returns almost completely to its original value. For the compass application, the two horizontal plane components of the earth´s magnetic field have to be measured. So a package with two orthogonally aligned Hall-sensors was developed