DATA SHEET
HAL 5xy
2. Functional Description
The HAL 5xx sensors are monolithic integrated circuits
which switch in response to magnetic fields. If a mag-
netic 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 induc-
tion of magnets at higher temperatures. If the magnetic
field exceeds the threshold levels, the open drain out-
put switches to the appropriate state. The built-in hys-
teresis eliminates oscillation and provides switching
behavior of output without bouncing.
Magnetic offset caused by mechanical stress is com-
pensated for by using the “switching offset compensa-
tion 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. Subse-
quently, the open drain output switches to the appropri-
ate state. The time from crossing the magnetic switch-
ing level to switching of output can vary between zero
and 1/f
osc
.
Shunt protection devices clamp voltage peaks at the
output pin and V
DD
pin together with external series
resistors. Reverse current is limited at the V
DD
pin by
an internal series resistor up to
−15
V. No external
reverse protection diode is needed at the V
DD
pin for
reverse voltages ranging from 0 V to
−15
V.
V
DD
1
Reverse
Voltage &
Overvoltage
Protection
HAL 5xy
HAL 5xx
Temperature
Dependent
Bias
Hysteresis
Control
Short Circuit &
Overvoltage
Protection
Hall Plate
Switch
Comparator
Output
OUT
3
Clock
GND
2
Fig. 2–1:
HAL 5xx block diagram
f
osc
t
B
B
ON
t
V
OUT
V
OH
V
OL
t
I
DD
1/f
osc
= 16
μs
t
f
t
Fig. 2–2:
Timing diagram
Micronas
Jan. 11. 2010; DSH000020_004EN
7
MICRONAS [ MICRONAS ]
