HAL856UT-A datasheet(7/42 Pages) MICRONAS

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DATA SHEET

HAL856

Micronas

March 23, 2010; DSH000142_002EN

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

page 9.

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-

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.

Fig. 2–1: Programming with VDD modulation

Fig. 2–2: HAL856 block diagram

HAL

856

VDD

GND

DATA

Temperature

Oscillator

Switched

A/D

Digital

DATA

VDD

GND

EEPROM Memory

Bandgap

Reference

Dependent

Bias

Hall Plate

Converter

Signal

Processing

Supply

Lock

Level

Control

Current Output

Detection

and Protection

Devices

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