DATA SHEET
HAL856
sumption. There is no transmission of the PWM signal
during the communication.
When no command is detected or processed and the
supply voltage is within the recommended operating
range the PWM or Biphase-M output is enabled.
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 consists of redun-
dant EEPROM cells. In addition, the sensor IC is
equipped with devices for overvoltage and reverse-
voltage protection at all pins.
2. Functional Description
2.1. General Function
The HAL856 is a monolithic integrated circuit which
provides an output signal proportional to the magnetic
flux through the Hall plate.
The external magnetic field component perpendicular
to the branded side of the package generates a Hall
voltage. The Hall IC is sensitive to magnetic north and
south polarity. This voltage is converted to a digital
value, processed in the Digital Signal Processing Unit
(DSP) according to the settings of the EEPROM regis-
ters, converted to the different digital output formats
(PWM and Biphase-M serial protocol) and provided by
an output current source. The function and the param-
eters for the DSP are explained in Section 2.2. on
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 programming the
EEPROM registers. The IC is addressed by modulat-
ing the supply voltage (see Fig. 2–1). After detecting a
command, the sensor reads or writes the memory and
answers with a digital modulation of the current con-
HAL
856
8
V
DD
(V)
6
5
V
DD
GND
DATA
Fig. 2–1:
Programming with V
DD
modulation
V
DD
Bandgap
Reference
and Protection
Devices
Temperature
Dependent
Bias
Oscillator
Switched
Hall Plate
A/D
Converter
Digital
Signal
Processing
Current Output
DATA
Supply
Level
Detection
GND
Lock
Control
EEPROM Memory
Fig. 2–2:
HAL856 block diagram
Micronas
I
DD
(A)
7
March 23, 2010; DSH000142_002EN
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MICRONAS [ MICRONAS ]
