TLE4997 Datasheet, PDF (29/36 Pages) Infineon Technologies AG – Programmable Linear Hall Sensor for Industrial Use

TLE4997I
Calibration
9
Calibration
A special hardware interface to an external computing system and measurement
equipment is required for calibration of the sensor. All calibration and setup bits can be
written into a random access memory (RAM). This allows the EEPROM to remain
untouched during the entire calibration process. Therefore, this temporary setup (using
the RAM only) does not stress the EEPROM—and even allows a pre-verification¹⁾ of the
setup before programming—as the number of EEPROM programming cycles is limited
to provide a high data endurance.
The digital signal processing is completely deterministic. This allows a two point
calibration in one step without iterations. The two magnetic fields (here described as two
“positions” of an external magnetic circuitry) need to be applied only once. Furthermore,
a complete setup and calibration procedure can be performed requiring only one
EEPROM programming cycle at the end²⁾.
After setting up the temperature coefficients, the calibrated Hall A/D Converter values of
both positions need to be read and the sensor output signals (using a DAC test mode)
need to be acquired for the corresponding end points. Using this data, the signal
processing parameters can be immediately calculated with a program running on the
external computing system.
Note: The calibration and programming process must be performed only at the
start of life of the device.
Table 17 Calibration Characteristics
Parameter
Symbol Limit Values
min. max.
Temperature of sensor at t_CAL
2 point calibration and
programming
10 30
2 point calibration
accuracy¹⁾
∆V_CAL1 -0.5 0.5
1) _{Setup and validation performed at start of life.}
Unit
Notes
°C
% of VDD In both positions
Note: Depending on the application and external instrumentation setup, the accuracy of
the 2 point calibration can be improved.
1) _{This feature is not required for a deterministic two-point setup to fulfill the specification.}
2) _{Details and basic algorithms for this step are available on request.}
Data Sheet
29
V 1.0, 2007-06