DATA SHEET
HAL1000
Reference Levels
The LOW-LEVEL and HIGH-LEVEL registers contain
the reference values of the comparator.
The Low-Level is programmable between 0 V and
V
DD
/2. The register can be changed in steps of
2.44 mV. The High-Level is programmable between
0 V and V
DD
in steps of 2.44 mV.
The four parameters Sensitivity, V
OQ
, Low-Level, and
High-Level define the switching points B
ON
and B
OFF
.
For calibration in the system environment, a 2-point
adjustment procedure (see Section 2.3.) is recom-
mended. The suitable parameter set for each sensor
can be calculated individually by this procedure.
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
temperature dependence of the magnetic sensitivity
can be matched to the magnet and the sensor assem-
bly. As a result, the switching points can be stabilized
over the full temperature range. The sensor can com-
pensate 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 4.2. on page 21 for the recom-
mended settings for different linear temperature coeffi-
cients.
LOCKR
By setting this 1-bit register, all registers will be locked,
and the sensor will no longer respond to any supply
voltage modulation. This bit is active after the first
power-off and power-on sequence after setting the
LOCK bit.
Sensitivity
The SENSITIVITY register contains the parameter for
the multiplier in the DSP. Sensitivity is programmable
between
−4
and 4 in steps of 0.00049. Sensitivity = 1
corresponds to an increase of the signal voltage by
V
DD
if the ADC-READOUT increases by 2048.
VOQ
Warning: The LOCKR register cannot be reset!
ADC-READOUT
The VOQ register contains the parameter for the adder
in the DSP. V
OQ
is the signal 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 signal voltage is limited to:
V
Signal max
= V
OQ
+ V
DD
This 14-bit register delivers the actual digital value of
the applied magnetic field after filtering but before the
signal processing. This register can be read out and is
the basis for the calibration procedure of the sensor in
the system environment.
Micronas
March 4, 2004; 6251-528-1DS
9
MICRONAS [ MICRONAS ]
