HAL805-1 Datasheet, PDF (11/30 Pages) Micronas – Programmable Linear Hall-Effect Sensor

DATA SHEET
HAL 805
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.
Low clamping voltage ≤ V_OUT1,2 ≤ High clamping voltage
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:
Sensitivity =
V_OUT1 − V_OUT2
ADC-READOUT1 − ADC-READOUT2
*
2048
V_DD
V_OQ = V_OUT1 −
ADC-READOUT1 * Sensitivity * V_DD
2048
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.
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
V
5
Clamp-high = 4.5 V
VOUT ₄
Calibration point 1
3
2
1
Clamp-low = 0.5 V
Calibration point 2
0
−30 −20 −10 0
10 20 30 °
Angle
Fig. 2–7: Example for output characteristics
Step 3: Locking the Sensor
The last step is activating the LOCK function with the
“LOCK” command. Please note that the LOCK function
becomes effective after power-down and power-up of
the Hall IC. The sensor is now locked and does not
respond to any programming or reading commands.
Warning: This register cannot be reset!
Micronas
Feb. 14, 2006; 6251-513-3DS
11