Linear Hall-Effect Sensors with PWM Bus

Note: The HAL 2850 is not recommended for new designs.

The HAL 2850 is a member of the Micronas HAL 28xy family of programmable linear Hall‑effect sensors. The devices are produced in a proven automotive submicron CMOS technology and are available in the very small leaded TO92UT package.

The HAL 2850 features a digital PWM output with slew‑rate control to enable fast, robust data transfer in harsh environments; the PWM signal can be decoded directly by any unit that measures duty cycle (typically a timer/capture unit in a microcontroller). The maximum PWM frequency is 2 kHz with 12‑bit resolution; the PWM frequency is customer‑programmable between 30 Hz and 2 kHz (with a given resolution). The open‑drain output with programmable slew rates supports excellent EMI performance of the overall system.

The device uses a temperature‑compensated Hall plate with spinning‑current offset compensation and includes a precise temperature sensor used to compensate both sensitivity and offset. Analog signals are converted to digital values and processed by digital signal processing (RISC processor), which prevents analog offsets, temperature shifts and mechanical stress from degrading the digital output. The HAL 2850 integrates A/D converters for the Hall plate and for the temperature sensor, a digital PWM interface, an EEPROM with redundancy and a lock function for calibration data and PWM configuration, and protection devices on all pins.

Major characteristics - magnetic field range, sensitivity, offset, output polarity, clamping levels, PWM frequency, and the temperature coefficients of sensitivity and offset - can be adjusted to the magnetic circuit by programming the non‑volatile memory.

The HAL 2850 is programmable via BiPhase‑M telegrams; no additional programming pin is required because programming is performed through the output pin. The sensor is supplied in the small leaded TO‑92UT package.