HAL805-1 Datasheet, PDF(9/30 Page) Micronas – Programmable Linear Hall-Effect Sensor

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HAL805-1 Datasheet, PDF (9/30 Pages) Micronas – Programmable Linear Hall-Effect Sensor

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DATA SHEET

HAL 805

Note: During application design, it should be taken

into consideration that the maximum and mini-

mum ADC-READOUT is not exceeded during

calibration and operation of the Hall IC. Conse-

quently, the maximum and minimum magnetic

fields that may occur in the operational range

of a specific application should not saturate the

A/D converter. Please note that the A/D con-

verter saturates at magnetic fields well above,

respectively below, the magnetic range limits.

This large safety band between specified mag-

netic range and true operational range helps to

avoid any saturation.

Range

The RANGE bits are the three lowest bits of the MODE

D converter.

Magnetic Field Range

â30 mT...30 mT

â40 mT...40 mT

â60 mT...60 mT

â75 mT...75 mT

â80 mT...80 mT

â90 mT...90 mT

â100 mT...100 mT

â150 mT...150 mT

RANGE

Filter

The FILTER bits are the three highest bits of the

MODE register; they define the â3 dB frequency of the

digital low pass filter.

â3 dB Frequency

80 Hz

160 Hz

500 Hz

1 kHz

2 kHz

FILTER

TC and TCSQ

The temperature dependence of the magnetic sensitiv-

ity can be adapted to different magnetic materials in

order to compensate for the change of the magnetic

strength with temperature. The adaption is done by

programming the TC (Temperature Coefficient) and

the TCSQ registers (Quadratic Temperature Coeffi-

cient). Thereby, the slope and the curvature of the tem-

perature dependence of the magnetic sensitivity can

be matched to the magnet and the sensor assembly.

As a result, the output voltage characteristic can be

fixed over the full temperature range. The sensor can

compensate for linear temperature coefficients ranging

from about â3100 ppm/K up to 400 ppm/K and qua-

dratic coefficients from about â5 ppm/KÂ² to 5 ppm/KÂ².

Please refer to Section 4.3. on page 23 for the recom-

mended settings for different linear temperature coeffi-

cients.

Sensitivity

The SENSITIVITY register contains the parameter for

the multiplier in the DSP. The Sensitivity is program-

mable between â4 and 4. For VDD = 5 V, the register

can be changed in steps of 0.00049. Sensitivity = 1

corresponds to an increase of the output voltage by

VDD if the ADC-READOUT increases by 2048.

For all calculations, the digital value from the magnetic

field of the A/D converter is used. This digital informa-

tion is readable from the ADC-READOUT register.

Sensitivity =

ÎVOUT * 2048

ÎADC-READOUT * VDD

VOQ

The VOQ register contains the parameter for the adder

in the DSP. VOQ is the output voltage without external

magnetic field (B = 0 mT, respectively ADC-READOUT

= 0) and programmable from âVDD up to VDD. For VDD

= 5 V, the register can be changed in steps of 4.9 mV.

Note: If VOQ is programmed to a negative voltage, the

maximum output voltage is limited to:

VOUTmax = VOQ + VDD

For calibration in the system environment, a 2-point

adjustment procedure (see Section 2.3.) is recom-

mended. The suitable Sensitivity and VOQ values for

each sensor can be calculated individually by this pro-

cedure.

Micronas

Feb. 14, 2006; 6251-513-3DS

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