DATA SHEET
TC and TCSQ
Note:
During application design, it should be taken
into consideration that the maximum and mini-
mum ADC-READOUT is not exceeded during
calibration and operation of the Hall IC. Conse-
quently, the maximum and minimum magnetic
fields that may occur in the operational range
of a specific application should not saturate the
A/D converter. Please note that the A/D con-
verter saturates at magnetic fields well above,
respectively below, the magnetic range limits.
This large safety band between specified mag-
netic range and true operational range helps to
avoid any saturation.
Range
The RANGE bits are the three lowest bits of the MODE
register; they define the magnetic field range of the A/
D converter.
Magnetic Field Range
−30
mT...30 mT
−40
mT...40 mT
−60
mT...60 mT
−75
mT...75 mT
−80
mT...80 mT
−90
mT...90 mT
−100
mT...100 mT
−150
mT...150 mT
RANGE
0
4
5
1
6
2
7
3
The temperature dependence of the magnetic sensitiv-
ity can be adapted to different magnetic materials in
order to compensate for the change of the magnetic
strength with temperature. The adaption is done by
programming the TC (Temperature Coefficient) and
the TCSQ registers (Quadratic Temperature Coeffi-
cient). Thereby, the slope and the curvature of the
temperature dependence of the magnetic sensitivity
can be matched to the magnet and the sensor assem-
bly. As a result, the output voltage characteristic can
be fixed over the full temperature range. The sensor
can compensate for linear temperature coefficients
ranging from about
−3100
ppm/K up to 400 ppm/K and
quadratic coefficients from about
−5
ppm/K² to 5 ppm/
K². Please refer to Section 4.3. on page 23 for the rec-
ommended settings for different linear temperature
coefficients.
Sensitivity
The SENSITIVITY register contains the parameter for
the multiplier in the DSP. The Sensitivity is program-
mable between
−4
and 4. For V
DD
= 5 V, the register
can be changed in steps of 0.00049. Sensitivity = 1
corresponds to an increase of the output voltage by
V
DD
if the ADC-READOUT increases by 2048.
For all calculations, the digital value from the magnetic
field of the A/D converter is used. This digital informa-
tion is readable from the ADC-READOUT register.
Sensitivity =
ΔV
OUT
* 2048
ΔADC-READOUT
* V
DD
VOQ
The VOQ register contains the parameter for the adder
in the DSP. V
OQ
is the output voltage without external
magnetic field (B = 0 mT, respectively ADC-READ-
OUT = 0) and programmable from
−V
DD
up to V
DD
. For
V
DD
= 5 V, the register can be changed in steps of
4.9 mV.
Note:
If V
OQ
is programmed to a negative voltage, the
maximum output voltage is limited to:
V
OUTmax
= V
OQ
+ V
DD
Filter
The FILTER bits are the three highest bits of the
MODE register; they define the
−3
dB frequency of the
digital low pass filter.
−3
dB Frequency
80 Hz
160 Hz
500 Hz
1 kHz
2 kHz
FILTER
0
1
2
3
4
For calibration in the system environment, a 2-point
adjustment procedure (see Section 2.3.) is recom-
mended. The suitable Sensitivity and V
OQ
values for
each sensor can be calculated individually by this pro-
cedure.
Micronas
Feb. 7, 2006; 6251-537-3DS
9
MICRONAS [ MICRONAS ]
