HAL320 Datasheet, PDF (3/13 Pages) List of Unclassifed Manufacturers – Differential Hall Effect Sensor IC

HAL320
Solderability
– Package SOT-89A and SOT-89B: according to
IEC68-2-58
– Package TO-92UA: according to IEC68-2-20
1V^DD
OUT
3
2
GND
Fig. 1: Pin configuration
HAL 320
V_DD
1
Reverse
Voltage &
Overvoltage
Temperature
Dependent
Bias
Hysteresis
Control
Short Circuit &
Overvoltage
Protection
Protection
Hall Plate
S1
Hall Plate
S2
Switch
Comparator
Output
OUT
3
GND
2
Clock
Fig. 2: HAL320 block diagram
Functional Description
f_osc
This Hall effect sensor is a monolithic integrated circuit
with 2 Hall plates 2.25 mm apart that switches in re-
sponse to differential magnetic fields. If magnetic fields
with flux lines at right angles to the sensitive areas are
t
applied to the sensor, the biased Hall plates force Hall
DB
voltages proportional to these fields. The difference of
the Hall voltages is compared with the actual threshold
level in the comparator. The temperature-dependent
DB_ON
bias increases the supply voltage of the Hall plates and
t
adjusts the switching points to the decreasing induction
of magnets at higher temperatures. If the differential
magnetic field exceeds the threshold levels, the open
V_OUT
V_OH
drain output switches to the appropriate state. The built-
V_OL
in hysteresis eliminates oscillation and provides switch-
ing behavior of the output without oscillation.
t
I_DD
Magnetic offset caused by mechanical stress at the Hall
plates is compensated for by using the “switching offset
compensation technique”: An internal oscillator pro-
vides a two phase clock (see Fig. 3). The difference of
the Hall voltages is sampled at the end of the first phase.
1/f_osc = 16 µs
t_f
t
At the end of the second phase, both sampled differen-
tial Hall voltages are averaged and compared with the
Fig. 3: Timing diagram
actual switching point. Subsequently, the open drain
output switches to the appropriate state. The amount of
time that elapses from crossing the magnetic switch lev-
el to the actual switching of the 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 re-
sistors. 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 values
ranging from 0 V to –15 V.
Micronas
3