iC-MZ DFN10

Description

Hall-effect device iC-MZ is a differential magnetic sensor used to scan pole wheels or ferro magnetic gear wheels. It contains two Hall sensors set 2.0 mm apart, a differential amplifier with a back-end comparator and a complementary line driver. A difference in field strength of the magnetic normal components at iC-MZ’s two Hall elements is amplified and evaluated as an analog signal and fed to the integrated line drivers as a complementary digital signal. The digital output signal tracks the change in sign of the field strength difference with a given hysteresis and thus provides a clear switch. With a moving gear or pole wheel the frequency of the tooth or pole pair corresponds to the frequency of the output signal. The amplified analog differential sensor signal is available for diagnostic purposes at pins A and NA. Once the device has been switched on the digital outputs are initially in a predefined start state with D at low and ND at high; the analog outputs A and NA switched to high impedance. Following a delay of about 200μs the analog outputs are activated and the status of the two Hall sensors is transmitted by the line drivers if the difference in field strength is sufficiently strong. The complementary line drivers are suitable for supply voltages of 4.5 to 36 V with output impedances between 40 and 110Ω. An integrated over temperature and under voltage monitor switches the output stages to high impedance in the event of error and activates the open drain output NERR. By activating the TEST input an additional mode of operation permits the device to be used as an independent two-channel line driver for diagnostic tests without involving the sensor and analog section. In this case, the outputs D and ND are controlled by the inputs A and NA. The analog section of the iC-MZ circuit is fed by an internal supply of 5V which is available at pin VPA for reference purpose. To improve signal quality, a capacitor can be connected to this pin.

Features