1.1. Features:

– switching offset compensation at typically 62 kHz

– operates from 3.8 V to 24 V supply voltage

– overvoltage protection at all pins

– reverse-voltage protection at VDD-pin

– magnetic characteristics are robust regarding

mechanical stress effects

– short-circuit protected open-drain output by thermal

shut down

– operates with static magnetic fields and dynamic

magnetic fields up to 10 kHz

– constant switching points over a wide supply voltage

range

– the decrease of magnetic flux density caused by rising

temperature in the sensor system is compensated

by a built-in negative temperature coefficient

of the magnetic characteristics

– ideal sensor for applications in extreme automotive

and industrial environments

– EMC corresponding to ISO 7637

2. Functional Description

The HAL 5xx sensors are monolithic integrated circuits

which switch in response to magnetic fields. If a magnetic

field with flux lines perpendicular to the sensitive

area is applied to the sensor, the biased Hall plate

forces a Hall voltage proportional to this field. The Hall

voltage is compared with the actual threshold level in

the comparator. The temperature-dependent bias

increases the supply voltage of the Hall plates and

adjusts the switching points to the decreasing induction

of magnets at higher temperatures. If the magnetic

field exceeds the threshold levels, the open drain output

switches to the appropriate state. The built-in hysteresis

eliminates oscillation and provides switching

behavior of output without bouncing.

Magnetic offset caused by mechanical stress is compensated

for by using the “switching offset compensation

technique”. Thus, an internal oscillator provides a

two-phase clock. The Hall voltage is sampled at the

end of the first phase. At the end of the second phase,

both sampled and actual Hall voltages are averaged

and compared with the actual switching point. Subsequently,

the open drain output switches to the appropriate

state. The time from crossing the magnetic switching

level to switching of output can vary between zero

and 1/fosc.

Shunt protection devices clamp voltage peaks at the

output pin and VDD pin together with external series

resistors. Reverse current is limited at the VDD pin by

an internal series resistor up to −15 V. No external

reverse protection diode is needed at the VDD pin for

reverse voltages ranging from 0 V to −15 V.