Note: HAL 824 and HAL 825 are not recommended for new designs. They can be replaced by HAL 835.
The HAL 824 and the HAL 825 expand the existing Hall-effect sensor family HAL 8xy. Both high-precision magnetic field sensors provide a ratiometric, linear output signal. This sensor family is designed to fulfill high requirements in respect of low temperature drifts of sensitivity and offset.
Due to the very low drifts of this sensor family, it can be used for applications with very high requirements on offset and sensitivity drift stability. This is mandatory for applications like throttle position detection, accelerator pedal sensing or current measurement.
The sensors provide either a ratiometric analog output signal or a multiplexed analog output. In multiplex analog output mode, the sensor transmits LSN and MSN of the output value separately. This enables the sensor to transmit a signal with 14-bit accuracy.
Major characteristics like magnetic field range, output format, sensitivity, the output voltage at zero magnetic field (VOQ), and the temperature coefficients can easily be adjusted to the magnetic circuit (linear and quadratic) by programming the non- volatile memory.
Both sensors are available in the very small leaded packageTO92UT.
Block diagram – system architecture
The HAL 82x sensors are produced in a proven automotive submicron CMOS technology.
The HAL 82x features a temperature-compensated Hall plate with choppered offset compensation, an A/D converter, digital signal processing, a push-pull output, an EEPROM memory with redundancy and lock function for the calibration data and the data register information, a serial interface for programming the EEPROM, and protection devices on all pins.
The HAL 82x is programmable by modulating the supply voltage. No additional programming pin is needed.
The internal digital signal processing is a great benefit because analog offsets, temperature shifts, and mechanical stress do not degrade the sensor accuracy.