115 Northeast Cutoff, Box 15036

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

RATIOMETRIC,

LINEAR HALL-EFFECT SENSORS

FOR HIGH-TEMP. OPERATION

CHARACTERISTICS DEFINITIONS

Ratiometry. The A3507– and A3508– feature a ratiometric

output. The quiescent voltage output and sensitivity are

proportional to the supply voltage (ratiometric).

The per cent ratiometric change in the quiescent voltage

output is defined as

∆V

OQ(

V

x 100%

(4)

V

and the per cent ratiometric change in sensitivity is defined as

∆Sens

(

Sens

x 100%

(5)

V

Linearity and Symmetry. The on-chip output stage is de-

signed to provide a linear output to within 500 mV of either rail

with a supply voltage of 5 V. This is equivalent to approxi-

mately

±800 gauss of ambient field. Although application of

stronger magnetic fields will not damage these devices, it will

force the output into a non-linear region. Linearity in per cent

is measured and defined as

Lin+ =

V

x 100%

(6)

2 (V

Lin– =

V

x 100%

(7)

2 (V

and output symmetry as

Sym =

V

x 100%

(8)

V

Quiescent Voltage Output. In the quiescent state (no mag-

netic field), the output is ideally equal to one-half of the supply

voltage over the operating voltage and temperature range (V

OQ

∪ V

considerations, there is a tolerance on the quiescent voltage

output and on the quiescent voltage output as a function of

supply voltage and ambient temperature. For purposes of

specification, the quiescent voltage output as a function of

temperature is defined as

∆V

OQ(

V

°C)

(1)

Sens

(25

°C)

This calculation yields the device’s equivalent accuracy,

over the operating temperature range, in gauss.

Sensitivity. The presence of a south-pole magnetic field

perpendicular to the package face (the branded surface) will

increase the output voltage from its quiescent value toward the

supply voltage rail by an amount proportional to the magnetic

field applied. Conversely, the application of a north pole will

decrease the output voltage from its quiescent value. This

proportionality is specified as the sensitivity of the device and

is defined as

Sens =

V

(2)

1000 G

The stability of sensitivity as a function of temperature is

defined as

∆Sens

(

Sens

°C)

x 100%

(3)

Sens

(25

°C)