A1302 datasheet(4/8 Pages) ALLEGRO

4 / 8 page

Continuous-Time Ratiometric

Linear Hall Effect Sensors

A1301 and

A1302

Allegro MicroSystems, Inc.

115 Northeast Cutoff, Box 15036

Worcester, Massachusetts 01615-0036 (508) 853-5000

www.allegromicro.com

Characteristic Definitions

Quiescent Output Voltage.

In the quiescent state (no sig-

nificant magnetic field: B = 0), the output, VOUTQ, equals one

half of the supply voltage, VCC, throughout the entire operating

ranges of VCC and ambient temperature, TA. Due to internal

component tolerances and thermal considerations, there is a

tolerance on the quiescent output voltage, ΔVOUTQ, which is

a function of both ΔVCC and ΔTA. For purposes of specifica-

tion, the quiescent output voltage as a function of temperature,

ΔVOUTQ(ΔT

A), is defined as:

where Sens is in mV/G, and the result is the device equivalent

accuracy, in gauss (G), applicable over the entire operating tem-

perature range.

Sensitivity.

The presence of a south-polarity (+B) magnetic

field, perpendicular to the branded face of the device package,

increases the output voltage, VOUT, in proportion to the magnetic

field applied, from VOUTQ toward the VCC rail. Conversely, the

application of a north polarity (–B) magnetic field, in the same

orientation, proportionally decreases the output voltage from its

quiescent value. This proportionality is specified as the magnetic

sensitivity of the device and is defined as:

The stability of the device magnetic sensitivity as a function of

ambient temperature, ΔSens (ΔT

A) (%) is defined as:

Ratiometric.

The A1301 and A1302 feature a ratiometric

output. This means that the quiescent voltage output, VOUTQ,

and the magnetic sensitivity, Sens, are proportional to the supply

voltage, VCC.

The ratiometric change (%) in the quiescent voltage output is

defined as:

and the ratiometric change (%) in sensitivity is defined as:

Linearity and Symmetry.

The on-chip output stage is

designed to provide linear output at a supply voltage of 5 V.

Although the application of very high magnetic fields does not

damage these devices, it does force their output into a nonlinear

region. Linearity in percent is measured and defined as:

and output symmetry as:

ΔVOUTQ(ΔΤ

Α)

Sens(25ºC)

VOUTQ(Τ

Α)

VOUTQ(25ºC)

–

(1)

VOUT(–B) VOUT(+B)

Sens

–

ΔSens(ΔΤ

Α)

Sens(Τ

Α)

Sens(25ºC)

–

× 100%

(2)

(3)

VCC

VOUTQ(VCC) VOUTQ(5V)

ΔVOUTQ(ΔV) =

× 100%

(4)

VCC 5V

× 100%

ΔSens(ΔV)

Sens(VCC)

Sens(5V)

(5)

× 100%

Lin+

2 (VOUT(+B½) –VVOUTQ )

–

VOUT(+B) VOUTQ

(6)

× 100%

Lin–

2(VOUT(–B½) –VOUTQ)

–

VOUT(–B) VOUTQ

(7)

–

× 100%

Sym

VOUT(+B)

VOUTQ –VOUT(–B)

VOUTQ

(8)

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