HAL880 datasheet(6/34 Pages) MICRONAS

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HAL880

DATA SHEET

Feb. 23, 2009; DSH000152_001EN

Micronas

2. Functional Description

2.1. General Function

The HAL880 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

information inside the sensor. 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: HAL880 block diagram

HAL

880

VDD

GND

OUT

analog

digital

VDD

Internally

Temperature

Oscillator

Switched

Digital

D/A

Analog

GND

EEPROM Memory

Lock Control

stabilized

Supply and

Protection

Devices

Dependent

Bias

Protection

Devices

Hall Plate

Signal

Processing

Converter

Output

A/D

Converter

Open-circuit,

Overvoltage,

Undervoltage

Detection

Open-Circuit

Detection

OUT

VDD

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