HAL805 Datasheet, PDF (17/24 Pages) Micronas – Programmable Linear Hall Effect Sensor

PRELIMINARY DATA SHEET
HAL 805
4. Application Notes
4.1. Application Circuit
For EMC protection, it is recommended to connect one
ceramic 4.7 nF capacitor each between ground and
the supply voltage, respectively the output voltage pin.
In addition, the input of the controller unit should be
pulled-down with a 4.7 kOhm resistor and a ceramic
4.7 nF capacitor.
Please note that during programming, the sensor will
be supplied repeatedly with the programming voltage
of 12 V for 100 ms. All components connected to the
V_DD line at this time must be able to resist this voltage.
V_DD
4.7 nF
HAL805
OUT
4.7 nF
4.7 nF
GND
µC
4.7 kΩ
Fig. 4–1: Recommended application circuit
4.2. Use of two HAL 805 in Parallel
Two different HAL 805 sensors which are operated in
parallel to the same supply and ground line can be
programmed individually. In order to select the IC
which should be programmed, both Hall ICs are inacti-
vated by the “Deactivate” command on the common
supply line. Then, the appropriate IC is activated by an
“Activate” pulse on its output. Only the activated sen-
sor will react to all following read, write, and program
commands. If the second IC has to be programmed,
the “Deactivate” command is sent again, and the sec-
ond IC can be selected.
V_DD
OUT A & Select A
10 nF
HAL 805
Sensor A
4.7 nF
HAL 805 ^{OUT B & Select B}
Sensor B
4.7 nF
GND
Fig. 4–2: Parallel operation of two HAL 805
4.3. Temperature Compensation
The relationship between the temperature coefficient
of the magnet and the corresponding TC and TCSQ
codes for linear compensation is given in the following
table. In addition to the linear change of the magnetic
field with temperature, the curvature can be adjusted
as well. For this purpose, other TC and TCSQ combi-
nations are required which are not shown in the table.
Please contact MICRONAS for more detailed informa-
tion on this higher order temperature compensation.
The HAL 800 and HAL 805 contain the same tempera-
ture compensation circuits. If an optimal setting for the
HAL 800 is already available, the same settings may
be used for the HAL 805.
Temperature
TC
Coefficient of
Magnet (ppm/K)
400
31
300
28
200
24
100
21
0
18
−50
17
−90
16
−130
15
−170
14
−200
13
−240
12
−280
11
−320
10
−360
9
−410
8
−450
7
−500
6
−550
5
−600
4
−650
3
−700
2
−750
1
TCSQ
6
7
8
9
10
10
11
11
11
12
12
12
13
13
13
13
14
14
14
14
15
15
Micronas
17