3515
AND
3516
RATIOMETRIC,
LINEAR
HALL-EFFECT SENSORS
CHARACTERISTICS DEFINITIONS
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
CC
/
2
). Due to internal component tolerances and thermal
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(∆T)
=
V
OQ(TA)
– V
OQ(25°C)
Sens
(25°C)
Ratiometry.
The A3515xUA and A3516xUA 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)
=
V
OQ(VCC)
/ V
OQ(5V)
V
CC
/ 5 V
x 100%
(4)
(1)
and the per cent ratiometric change in sensitivity is defined as
∆Sens
(∆V)
=
Sens
(VCC)
/ Sens
(5V)
V
CC
/ 5 V
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
V
O(500G)
– V
O(-500G)
1000 G
x 100%
(5)
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
V
O(500G)
– V
OQ
2 (V
O(250G)
– V
OQ
)
V
O(-500G)
– V
OQ
2 (V
O(-250G)
– V
OQ
)
Lin+ =
(2)
x 100%
(6)
Sens =
The stability of sensitivity as a function of temperature is
defined as
∆Sens
(∆T)
=
Sens
(TA)
– Sens
(25°C)
Sens
(25°C)
Lin– =
x 100%
(7)
and output symmetry as
x 100%
(3)
Sym =
V
O(500G)
– V
OQ
V
OQ
– V
O(-500G)
x 100%
(8)
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