HAL 805
DATA SHEET
Clamping Voltage
2.3. Calibration Procedure
2.3.1. General Procedure
The output voltage range can be clamped in order to
detect failures like shorts to VDD or GND or an open
circuit.
For calibration in the system environment, the applica-
tion kit from Micronas is recommended. It contains the
hardware for the generation of the serial telegram for
programming and the corresponding software for the
input of the register values.
The CLAMP-LOW register contains the parameter for
the lower limit. The lower clamping voltage is program-
mable between 0 V and VDD/2. For VDD = 5 V, the reg-
ister can be changed in steps of 2.44 mV.
In this section, programming of the sensor using this
programming tool is explained. Please refer to
Section 5. on page 25 for information about program-
ming without this tool.
The CLAMP-HIGH register contains the parameter for
the upper limit. The upper clamping voltage is pro-
grammable between 0 V and VDD. For VDD = 5 V, in
steps of 2.44 mV.
For the individual calibration of each sensor in the cus-
tomer application, a two point adjustment is recom-
mended (see Fig. 2–7 for an example). When using
the application kit, the calibration can be done in three
steps:
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.
Step 1: Input of the registers which need not be
adjusted individually
The magnetic circuit, the magnetic material with its
temperature characteristics, the filter frequency, and
low and high clamping voltage are given for this appli-
cation.
Warning: This register cannot be reset!
ADC-READOUT
Therefore, the values of the following registers should
be identical for all sensors of the customer application.
This 14-bit register delivers the actual digital value of
the applied magnetic field before the signal process-
ing. This register can be read out and is the basis for
the calibration procedure of the sensor in the system
environment.
– FILTER
(according to the maximum signal frequency)
– RANGE
(according to the maximum magnetic field at the
sensor position)
– TC and TCSQ
(depends on the material of the magnet and the
other temperature dependencies of the application)
– CLAMP-LOW and CLAMP-HIGH
(according to the application requirements)
Write the appropriate settings into the HAL805 regis-
ters.
10
Feb. 14, 2006; 6251-513-3DS
Micronas
MICRONAS [ MICRONAS ]
