HAL805
PRELIMINARY DATA SHEET
Note: During application design, it should be taken
into consideration that the maximum and minimum
ADC-READOUT is not exceeded during calibration
and operation of the Hall IC. Consequently, the maxi-
mum 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 converter saturates at magnetic fields well above,
respectively below, the magnetic range limits. This
large safety band between specified magnetic range
and true operational range helps to avoid any satura-
tion.
TC and TCSQ
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 tem-
perature dependence of the magnetic sensitivity can
be matched to the magnet and the sensor assembly.
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 qua-
dratic coefficients from about −5 ppm/K² to 5 ppm/K².
Please refer to Section 4.3. on page 17 for the recom-
mended settings for different linear temperature coeffi-
cients.
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
Sensitivity
0
4
5
1
6
2
7
3
The SENSITIVITY register contains the parameter for
the multiplier in the DSP. The Sensitivity is program-
mable between −4 and 4. For VDD = 5 V, the register
can be changed in steps of 0.00049. Sensitivity = 1
corresponds to an increase of the output voltage by
VDD 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.
∆VOUT * 2048
Sensitivity =
∆ADC-READOUT * VDD
VOQ
Filter
The VOQ register contains the parameter for the adder
in the DSP. VOQ is the output voltage without external
magnetic field (B = 0 mT, respectively ADC-READOUT
= 0) and programmable from −VDD up to VDD. For VDD
= 5 V, the register can be changed in steps of 4.9 mV.
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
FILTER
Note: If VOQ is programmed to a negative voltage, the
maximum output voltage is limited to:
0
1
2
3
4
160 Hz
VOUTmax = VOQ + VDD
500 Hz
For calibration in the system environment, a 2-point
adjustment procedure (see Section 2.3.) is recom-
mended. The suitable Sensitivity and VOQ values for
each sensor can be calculated individually by this pro-
cedure.
1 kHz
2 kHz
8
Micronas
MICRONAS [ MICRONAS ]
