Compared with the standard Hall switches, the HAL 1000 offers full in-system programmability. The major sensor characteristics, the two switching points BON and BOFF, and the output behavior are programmable for the specific application.
The HAL 1000 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.
Due to the digital signal processing, analog offsets, temperature shifts, and mechanical stress effects do not degrade the sensor accuracy.
The HAL 1000 is programmable by modulating the supply voltage . No additional programming pin is needed . The tolerances of the sensor, the magnet, and the mechanical positioning can be compensated via programming for the final assembly. This offers a low-cost alternative for all applications that presently require mechanical adjustment.
The sensor is designed for the use in harsh automotive and industrial applications with nominal supply voltage of 5 V in the junction temperature range from −40 °C up to 170 °C . The HAL 1000 is available in the leaded package TO92UT.
Block diagram – system architecture
The HAL 1000 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 1000 is equipped with devices for overvoltage and reverse-voltage protection at all pins.