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TLE4998S3 Datasheet, PDF (26/39 Pages) Infineon Technologies AG – Programmable Linear Hall Sensor
TLE4998S
Temperature Compensation
8
Temperature Compensation
The magnetic field strength of a magnet depends on the temperature. This material
constant is specific for the different magnet types. Therefore, the TLE4998S offers a
second-order temperature compensation polynomial, by which the Hall signal output is
multiplied in the DSP. There are three parameters for the compensation:
• Reference temperature T0
• A linear part (1st order) TC1
• A quadratic part (2nd order) TC2
The following formula describes the sensitivity dependent on the temperature in relation
to the sensitivity at the reference temperature T0:
STC(T) = 1 + TC1 × (T – T0) + TC2 × (T – T0)2
For more information, please refer to the signal processing flow in Figure 6.
The full temperature compensation of the complete system is done in two steps:
1. Pre-calibration in the Infineon final test
The parameters TC1, TC2, T0 are set to maximally flat temperature characteristics
with respect to the Hall probe and internal analog processing parts.
2. Overall system calibration
The typical coefficients TC1, TC2, T0 of the magnetic circuitry are programmed. This
can be done deterministically, as the algorithm of the DSP is fully reproducible. The
final setting of the TC1, TC2, T0 values depend on the pre-calibrated values.
Table 15 Temperature Compensation
Parameter
Symbol Limit Values Unit
Notes
min. max.
Register size TC1
TL
1st order coefficient TC1 TC1
-
9
bit
Unsigned integer values
-1000 2500 ppm/ °C 1)
Quantization steps of TC1 qTC1
15.26 ppm/ °C
Register size TC2
TQ
2nd order coefficient TC2 TC2
-
8
-4 4
bit
Unsigned integer values
ppm/ °C² 2)
Quantization steps of TC2 qTC2
0.119 ppm/ °C²
Reference temp.
T0
- 48 64 °C
Quantization steps of T0 qT0
1
°C
3)
1) Full adjustable range: -2441 to +5355 ppm/°C, can be only used after confirmation by Infineon
2) Full adjustable range: -15 to +15 ppm/°C², can be only used after confirmation by Infineon
3) Handled by algorithm only (see Application Note)
Data Sheet
26
V 1.0, 2008-07