HAL824 View Datasheet(PDF) - Micronas

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Description

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HAL824

High-Precision Programmable Linear Hall-Effect Sensor

Micronas 

HAL 82x

DATA SHEET

2. Functional Description

2.1. General Function

The HAL82x 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 (ratiometric behavior).

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 an analog voltage with ratiometric

behavior, and stabilized by a push-pull output transis-

tor stage. The function and the parameters for the DSP

are explained in Section 2.2. on page 8.

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). In the supply

voltage range from 4.5 V up to 5.5 V, the sensor gen-

erates an analog output voltage. After detecting a

command, 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. Several sensors in parallel to the same supply

and ground line can be programmed individually. The

selection of each sensor is done via its output pin.

The open-circuit detection provides a defined output

voltage if the VDD or GND line is broken. Internal tem-

perature compensation circuitry and the choppered off-

set compensation enables operation over the full tem-

perature 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 redundant and non-

redundant EEPROM cells. The non-redundant

EEPROM cells are only used to store production infor-

mation inside the sensor. In addition, the sensor IC is

equipped with devices for overvoltage and reverse-

voltage protection at all pins.

HAL

82x

8

VDD

7

6

5

VDD

OUT

GND

digital

Fig. 2–1: Programming with VDD modulation

analog

VDD

Internally

stabilized

Supply and

Protection

Devices

Temperature

Dependent

Bias

Oscillator

Open-circuit,

Overvoltage,

Undervoltage

Detection

Protection

Devices

Switched

Hall Plate

A/D

Converter

Digital

Signal

Processing

D/A

Converter

Analog

Output

50 Ω 50 Ω

OUT

GND

Supply

Level

Detection

EEPROM Memory

Lock Control

Fig. 2–2: HAL82x block diagram

Digital

Output

6

Feb. 3, 2009; DSH000143_003EN

Open-circuit

Detection

Micronas

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