The HAL 1002 is the improved successor of the HAL 1000 Hall switch. The major sensor characteristics, the two switching points BON and BOFF, are programmable for the application. The sensor can be programmed to be unipolar or latching, sensitive to the magnetic north pole or sensitive to the south pole, with normal or with an electrically inverted output signal.
The HAL 1002 features a temperature-compensated Hall plate with choppered offset compensation, an A/D converter, digital signal processing, a push-pull output stage, an EEPROM memory with redundancy and lock function for the calibration data, a serial interface for programming the EEPROM, and protection devices at all pins.
The HAL 1002 is programmable by modulating the supply voltage. Programming is simplifi ed through the use of a 2-point calibration. The tolerances of the sensor, the magnet, and the mechanical positioning can be compensated for the fi nal assembly. The temperature compensation of the Hall IC can be tailored to all common magnetic materials. This enables operation over the full temperature range with constant switching points. The calculation of the individual sensor characteristics and the programming of the EEPROM memory can easily be done with a PC and the application kit from Micronas.
The sensor is designed for the use in hostile industrial and automotive applications in the ambient temperature range from −40 °C up to 150 °C.
The HAL 1002 is available in the leaded package TO92UT-2.
Block diagram – system architecture
The HAL 1002 is a monolithic integrated circuit which provides a digital output signal. The sensor is based on the HAL 8xx design. All blocks before the comparator are identical to the HAL 810 and the signal processing is very similar.
The Hall plate is sensitive to magnetic north and south polarity. The external magnetic field component perpendicular to the branded side of the package generates a Hall voltage. This voltage is converted to a digital value and processed in the Digital Signal Processing Unit (DSP) according to the settings of the EEPROM registers.
The setting of the LOCK register disables the programming of the EEPROM memory for all time. This register cannot be reset.
As long as the LOCK register is not set, the output characteristic can be adjusted by programming the EEPROM registers. The IC is addressed by modulating the supply voltage. In the supply voltage range from 4.5 V up to 5.5 V, the sensor generates an analog output voltage. After detecting a command, the sensor reads or writes the memory and answers with a digital signal on the output pin. The digital output is switched off during the communication.
Internal temperature compensation circuitry and the choppered offset compensation enables operation over the full temperature range with minimal changes of the switching points. The circuitry also rejects offset shifts due to mechanical stress from the package. The non-volatile memory consists of redundant EEPROM cells. In addition, the HAL 1002 is equipped with devices for overvoltage and reverse-voltage protection at all pins.