In-System Programmable Hall Switch

The HAL 1002 is the improved successor to the HAL 1000 Hall switch. The two switching points (B_ON and B_OFF) are programmable to match the application; the device can be configured as unipolar or latching, set sensitive to the magnetic north or south pole, and operated with either a normal or electrically inverted output signal. The HAL 1002 is a monolithic integrated circuit providing a digital output signal and is based on the HAL 8xy design - all blocks before the comparator are identical to the HAL 810 and the signal processing is very similar.

The HAL 1002 incorporates a temperature‑compensated Hall plate with choppered offset compensation, an A/D converter, digital signal processing (DSP), and a push‑pull output stage. It includes an EEPROM with redundant cells and a lock function for calibration data, a serial interface for EEPROM programming, and protection devices on all pins.

The IC is addressed by modulating the supply voltage; no additional programming pin is required. Programming is simplified by a two‑point calibration: the output can be adjusted directly to the input signal (e.g., mechanical angle, distance or current) so that tolerances of the sensor, the magnet and the mechanical positioning are compensated in the final assembly. Calculation of individual sensor characteristics and EEPROM programming can be performed with a PC and the TDK‑Micronas application kit.

The Hall plate is sensitive to both magnetic polarities: the external magnetic field component perpendicular to the branded side of the package generates a Hall voltage, which is converted to a digital value and processed in the DSP according to the EEPROM register settings. In the supply voltage range from 4.5 V to 5.5 V the sensor generates an analog output voltage; after detecting a command the sensor reads or writes the memory and replies with a digital signal on the output pin. The digital output is switched off during the communication. Setting the LOCK register permanently disables EEPROM programming - this register cannot be reset.

Internal temperature compensation and choppered offset compensation minimize changes of the switching points over temperature and reject offset shifts caused by mechanical stress on the package.

The HAL 1002 is designed for hostile industrial and automotive applications and operates in the ambient temperature range from −40 °C to +150 °C. The device is available in the leaded TO92UT package and is equipped with overvoltage and reverse‑voltage protection devices at all pins.