HAL805
PRELIMINARY DATA SHEET
10
Micronas
Step 2: Calculation of V
OQ
and Sensitivity
The calibration points 1 and 2 can be set inside the
specified range. The corresponding values for V
OUT1
and V
OUT2
result from the application requirements.
For highest accuracy of the sensor, calibration points
near the minimum and maximum input signal are rec-
ommended. The difference of the output voltage
between calibration point 1 and calibration point 2
should be more than 3.5 V.
Set the system to calibration point 1 and read the reg-
ister ADC-READOUT. The result is the value ADC-
READOUT1.
Now, set the system to calibration point 2, read the
register ADC-READOUT again, and get the value
ADC-READOUT2.
With these values and the target values V
OUT1
and
V
OUT2
, for the calibration points 1 and 2, respectively,
the values for Sensitivity and V
OQ
are calculated as:
This calculation has to be done individually for each
sensor.
Next, write the calculated values for Sensitivity and
V
OQ
into the IC for adjusting the sensor.
The sensor is now calibrated for the customer applica-
tion. However, the programming can be changed again
and again if necessary.
Step 3: Locking the Sensor
The last step is activating the LOCK function with the
“
LOCK
”
command. The sensor is now locked and does
not respond to any programming or reading com-
mands.
Warning: This register cannot be reset!
2.3.2. Calibration of the Angle Sensor
The following description explains the calibration pro-
cedure using an angle sensor as an example. The
required output characteristic is shown in Fig. 2
–
7.
–
the angle range is from
25
°
to 25
°
–
temperature coefficient of the magnet:
500 ppm/K
Step 1: Input of the registers which need not be
adjusted individually
The register values for the following registers are given
for all applications:
–
FILTER
Select the filter frequency: 500 Hz
–
RANGE
Select the magnetic field range: 30 mT
–
TC
For this magnetic material: 6
–
TCSQ
For this magnetic material: 14
–
CLAMP-LOW
For our example: 0.5 V
–
CLAMP-HIGH
For our example: 4.5 V
Enter these values in the software, and use the
“
write
and store
”
command for permanently writing the val-
ues in the registers.
Low clamping voltage
≤
V
OUT1,2
≤
High clamping voltage
V
OUT1
V
OUT2
ADC-READOUT1
ADC-READOUT2
Sensitivity =
V
DD
2048
*
ADC-READOUT1 * Sensitivity * V
DD
2048
V
OQ
= V
OUT1
0
–
30
1
2
3
4
5
–
20
–
10
0
10
20
30
°
V
Angle
V
OUT
Clamp-high = 4.5 V
Calibration point 1
Clamp-low = 0.5 V
Calibration point 2
Fig. 2
–
7:
Example for output characteristics