HAL800 Datasheet, PDF (7/24 Pages) Micronas – Programmable Linear Hall Effect Sensor

HAL 800
2.2. Digital Signal Processing and EEPROM
The DSP is the major part of this sensor and performs
the signal conditioning. The parameters for the DSP
are stored in the EEPROM registers. The details are
shown in Fig. 2–3.
Terminology:
SENSITIVITY: name of the register or register value
Sensitivity: name of the parameter
The EEPROM registers consist of three groups:
Group 1 contains the registers for the adaption of the
sensor to the magnetic system:
MODE for selecting the magnetic field range and filter
frequency, TC and TCSQ for temperature characteris-
tics of the magnetic sensitivity.
Group 2 contains the registers for defining the output
characteristics: SENSITIVITY, VOQ, CLAMP-LOW,
and CLAMP-HIGH. The output characteristic of the
sensor is defined by these 4 parameters (see Fig. 2–4
and Fig. 2–5 for examples).
– The parameter V_OQ (Output Quiescent Voltage) cor-
responds to the output voltage at B = 0 mT.
– The parameter Sensitivity is defined as:
Sensitivity =
∆V_OUT
∆B
– The output voltage can be calculated as:
V_OUT ∼ Sensitivity × B + V_OQ
The output voltage range can be clamped by setting
the registers CLAMP-LOW and CLAMP-HIGH in order
to enable failure detection (such as short-circuits to
V_DD or GND).
Group 3 contains the Micronas registers and LOCK for
the locking of all registers. The Micronas registers are
programmed and locked during production and are
read-only for the customer. These registers are used
for oscillator frequency trimming, A/D converter offset
compensation, and several other special settings.
The ADC converts positive or negative Hall voltages
(operates with magnetic north and south poles at the
branded side of the package) in a digital value. This
signal is filtered in the Digital Filter and is readable in
the ADC-READOUT register as long as the LOCK bit
is not set.
Note: The ADC-READOUT values and the resolution
of the system depends on the filter frequency. Positive
values accord to a magnetic north pole on the branded
side of the package. Fig. 2–6 and Fig. 2–7 show typi-
cal ADC-READOUT values for the different magnetic
field ranges and filter frequencies.
6000
Filter = 500 Hz
ADC- ⁴⁰⁰⁰
READOUT
2000
0
–2000
–4000
–6000
–200–150–100 –50 0
Range 150 mT
Range 90 mT
Range 75 mT
Range 30 mT
50 100 150 200 mT
B
Fig. 2–6: Typical ADC-READOUT
versus magnetic field for filter = 500 Hz
Micronas
1500
Filter = 2 kHz
ADC- ¹⁰⁰⁰
READOUT
500
0
–500
–1000
–1500
–200–150–100 –50 0
Range 150 mT
Range 90 mT
Range 75 mT
Range 30 mT
50 100 150 200 mT
B
Fig. 2–7: Typical ADC-READOUT
versus magnetic field for filter = 2 kHz
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