A High-Temperature Sensor Based on Monolithic GaAs Hall IC

A high-temperature position sensor has been developed wfiich is based on a monolithic GaAs Hall IC. The three-stage Hall IC contains a Hall device with constant current source, a dual-gate MESFET differential amplifier and a source-follower. The differential amplifier delivers a low-frequency gain up to 350, the Hall MIC a sensitivity up to 180 V/Tesla. The main application is in automobile electronics, where in a high-temperature environment ($$ 180 C) a local amplification of the sensor signal is necessary with respect to high noise level. A new key technology with the synonym DIOM will be described, which ful fills simultaneously the reliability requirements of the sensor and the gain and uniformity demands of the differential amplifier.