HAL320
Differential Hall Effect Sensor IC
in CMOS technology
Introduction
The HAL 320 is a differential Hall switch produced in
CMOS technology. The sensor includes 2 temperature-
compensated Hall plates (2.25 mm apart) with active off-
set compensation, a differential amplifier with a Schmitt
trigger, and an open-drain output transistor (see Fig. 2).
The HAL 320 is a differential sensor which responds to
spatial differences of the magnetic field. The Hall volt-
ages at the two Hall plates, S
1
and S
2
, are amplified with
a differential amplifier. The differential signal is
compared with the actual switching level of the internal
Schmitt trigger. Accordingly, the output transistor is
switched on or off. The sensor has a bipolar switching
behavior and requires positive and negative values of
∆B
= B
S1
– B
S2
for correct operation.
Basically, there are two ways to generate the differential
signal
∆B:
– Rotating a multi-pole-ring in front of the branded side
of the package (see Fig. 4, Fig. 5, and Fig. 6).
– Back-bias applications:
A magnet on the back side of the package generates
a back-bias field at both Hall plates. The differential
signal
∆B
results from the magnetic modulation of the
back-bias field by a rotating ferromagnetic target.
The active offset compensation leads to constant mag-
netic characteristics over supply voltage and tempera-
ture.
The sensor is designed for industrial and automotive ap-
plications and operates with supply voltages from 4.5 V
to 24 V in the ambient temperature range from –40
°C
up to 150
°C.
The HAL 320 is an ideal sensor for target wheel applica-
tions, ignition timing, anti-lock brake systems, and revo-
lution counting in extreme automotive and industrial en-
vironments
The HAL 320 is available in two SMD-packages
(SOT-89A and SOT-89B) and in a leaded version
(TO-92UA).
Features:
– distance between Hall plates: 2.25 mm
– operates from 4.5 V to 24 V supply voltage
– switching offset compensation at 62 kHz
– overvoltage protection
– reverse-voltage protection of V
DD
-pin
– short-circuit protected open-drain output by thermal
shutdown
– operates with magnetic fields from DC to 10 kHz
– output turns low with magnetic south pole on branded
side of package and with a higher magnetic flux densi-
ty in sensitive area S1 as in S2
– on-chip temperature compensation circuitry mini-
mizes shifts of the magnetic parameters over temper-
ature and supply voltage range
– EMC corresponding to DIN 40839
Marking Code
Type
A
HAL320SF,
HAL320SO,
HAL320UA
320A
Temperature Range
E
320E
C
320C
Operating Junction Temperature Range (T
J
)
A:
T
J
= –40
°C
to +170
°C
E:
T
J
= –40
°C
to +100
°C
C:
T
J
= 0
°C
to +100
°C
The relationship between ambient temperature (T
A
) and
junction temperature (T
J
) is explained on page 11.
Hall Sensor Package Codes
HALXXXPA-T
Temperature Range: A, E, or C
Package: SF for SOT-89B
SO for SOT-89A
UA for TO-92UA
Type: 320
Example:
HAL320UA-E
→
Type: 320
→
Package: TO-92UA
→
Temperature Range: T
J
= –40
°C
to +100
°C
Hall sensors are available in a wide variety of packaging
versions and quantities. For more detailed information,
please refer to the brochure: “Ordering Codes for Hall
Sensors”.
2
Micronas
HAL320
Solderability
– Package SOT-89A and SOT-89B: according to
IEC68-2-58
– Package TO-92UA: according to IEC68-2-20
V
DD
1
OUT
Clock
GND
V
DD
1
Reverse
Voltage &
Overvoltage
Protection
Hall Plate
S1
Switch
Hall Plate
S2
HAL320
Temperature
Dependent
Bias
Hysteresis
Control
Short Circuit &
Overvoltage
Protection
Comparator
Output
OUT
3
3
2
GND
2
Fig. 1:
Pin configuration
Fig. 2:
HAL320 block diagram
Functional Description
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
applied to the sensor, the biased Hall plates force Hall
voltages proportional to these fields. The difference of
the Hall voltages 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 differential
magnetic field exceeds the threshold levels, the open
drain output switches to the appropriate state. The built-
in hysteresis eliminates oscillation and provides switch-
ing behavior of the output without oscillation.
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.
At the end of the second phase, both sampled differen-
tial Hall voltages are averaged and compared with the
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.
f
osc
t
DB
DB
ON
t
V
OUT
V
OH
V
OL
t
I
DD
1/f
osc
= 16
µs
t
f
t
Fig. 3:
Timing diagram
Micronas
3
HAL320
Absolute Maximum Ratings
Symbol
V
DD
–V
P
–I
DD
I
DDZ
V
O
I
O
I
Omax
I
OZ
T
S
T
J
Parameter
Supply Voltage
Test Voltage for Supply
Reverse Supply Current
Supply Current through
Protection Device
Output Voltage
Continuous Output On Current
Peak Output On Current
Output Current through
Protection Device
Storage Temperature Range
Junction Temperature Range
Pin No.
1
1
1
1
3
3
3
3
Min.
–15
–24
2)
–
–200
3)
–0.3
–
–
–200
3)
–65
–40
–40
Max.
28
1)
–
50
1)
200
3)
28
1)
30
250
3)
200
3)
150
150
170
4)
Unit
V
V
mA
mA
V
mA
mA
mA
°C
°C
1)
as long as T max is not exceeded
J
2)
with a 220
Ω
series resistance at pin
3)
t < 2 ms
4)
t < 1000h
1 corresponding to test circuit 1
Stresses beyond those listed in the “Absolute Maximum Ratings” may cause permanent damage to the device. This
is a stress rating only. Functional operation of the device at these or any other conditions beyond those indicated in the
“Recommended Operating Conditions/Characteristics” of this specification is not implied. Exposure to absolute maxi-
mum ratings conditions for extended periods may affect device reliability.
Recommended Operating Conditions
Symbol
V
DD
I
O
V
O
R
v
Parameter
Supply Voltage
Continuous Output On Current
Output Voltage
Series Resistor
Pin No.
1
3
3
1
Min.
4.5
–
–
–
Max.
24
20
24
270
Unit
V
mA
V
Ω
Micronas
5
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