2. Functional Description
2.1. General Function
The
HAL 800
is a monolithic integrated circuit which
provides an output voltage proportional to the mag-
netic flux through the Hall plate and proportional to the
supply voltage.
The external magnetic field component perpendicular
to the branded side of the package generates a Hall
voltage. This voltage is converted to a digital value,
processed in the Digital Signal Processing Unit (DSP)
according to the EEPROM programming, converted to
an analog voltage with ratiometric behavior, and stabi-
lized by a push-pull output transistor stage. The func-
tion and the parameters for the DSP are detailed
explained in
The setting of the LOCK register disables the program-
ming of the EEPROM memory for all time. This regis-
ter cannot be reset.
As long as the LOCK register is not set, the output
characteristic can be adjusted by modifying the
EEPROM registers. The IC is addressed by modulat-
ing the supply voltage
In the supply
voltage range from 4.5 V up to 5.5 V, the sensor gener-
ates an analog output voltage. After detecting a com-
mand, the sensor reads or writes the memory and
answers with a digital signal on the output pin. The
analog output is switched off during the communica-
tion.
Internal temperature compensation circuitry and the
choppered offset compensation enables operation
over the full temperature range with minimal changes
in accuracy and high offset stability. The circuitry also
rejects offset shifts due to mechanical stress from the
package. The non-volatile memory is equipped with
redundant EEPROM cells. In addition, the sensor IC is
equipped with devices for overvoltage and reverse volt-
age protection at all pins.
HAL
800A
8
V
DD
(V)
7
6
5
V
DD
V
OUT
(V)
V
DD
GND
OUT
digital
analog
Fig. 2–1:
Programming with V
DD
modulation
V
DD
Internally
stabilized
Supply and
Protection
Devices
Temperature
Dependent
Bias
Oscillator
Protection
Devices
Switched
Hall Plate
A/D
Converter
Digital
Signal
Processing
D/A
Converter
Analog
Output
100
Ω
OUT
EEPROM Memory
Supply
Level
Detection
Lock Control
GND
Digital
Output
Fig. 2–2:
HAL800 block diagram
Micronas
5
MICRONAS [ MICRONAS ]
