A1363LU Datasheet, PDF (14/29 Pages) Allegro MicroSystems – Low Noise, High Precision, Programmable Linear Hall Effect Sensor IC

A1363LU
Low Noise, High Precision, Programmable Linear Hall Effect Sensor IC
With Advanced Temperature Compensation
And High Bandwidth (120 kHz) Analog Output
considerations, the Quiescent Voltage Output, V_OUT(Q) , may drift
from its nominal value through the operating ambient tempera-
ture, T_A . The Quiescent Voltage Output Drift Through Tempera-
ture Range, Δ_VOUT(Q)TC , is defined as:
∆V_OUT(Q)TC = V_OUT(Q)(TA) –V_{OUT(Q)EXPECTED(TA)}
(5)
∆V_OUT(Q)TC should be calculated using the actual measured
values of ∆V_OUT(Q)(TA) and ∆V_{OUT(Q)EXPECTED(TA)} rather than
programming target values.
Sensitivity (Sens) The presence of a south polarity magnetic
field, perpendicular to the branded surface of the package face,
increases the output voltage from its quiescent value toward the
supply voltage rail. The amount of the output voltage increase is
proportional to the magnitude of the magnetic field applied.
Conversely, the application of a north polarity field decreases the
output voltage from its quiescent value. This proportionality is
specified as the magnetic sensitivity, Sens (mv/G), of the device,
and it is defined as:
Step Size section for a conceptual explanation.
Sensitivity Programming Resolution ( Err_PGSENS ) Refer to the
Quiescent Voltage Output Programming Resolution section for a
conceptual explanation.
Sensitivity Temperature Coefficient (TC_SENS) Device sensi-
tivity changes as temperature changes, with respect to its pro-
grammed sensitivity temperature coefficient, TC_SENS . TC_SENS
is programmed at 150°C, and calculated relative to the nominal
sensitivity programming temperature of 25°C. TC_SENS (%/°C) is
defined as:
TC_SENS
=
^{SensSTe2n–sTS1ensT1}

× 100%_

_T2¹_–T1
,
(7)
where T1 is the nominal Sens programming temperature of 25°C,
and T2 is the TC_SENS programming temperature of 150°C. The
expected value of Sens over the full ambient temperature range,
Sens_EXPECTED(TA), is defined as:
Sens_EXPECTED(TA) = Sens_T1 × [100% + TC_SENS (T_A –T1)] . ₍₈₎
Sens
=
V_OUT(BPOS) – V_OUT(BNEG)
BPOS – BNEG
,
(6)
where BPOS and BNEG are two magnetic fields with opposite
polarities.
Initial Unprogrammed Sensitivity ( Sens_init ) Before any pro-
gramming, Sensitivity has a nominal value that depends on the
SENS_COARSE bits setting. Each A1363 variant has a different
SENS_COARSE setting.
Sensitivity Programming Range (Sens_PR) The magnetic sensi-
tivity, Sens, can be programmed around its initial value within the
sensitivity range limits: Sens_PR(min) and Sens_PR(max). Exceed-
ing the specified Sensitivity Range will cause Sensitivity Drift
Through Temperature Range ΔSens_TC to deteriorate beyond the
specified values. Refer to the Quiescent Voltage Output Range
section for a conceptual explanation of how value distributions
and ranges are related.
Average Fine Sensitivity Programming Step Size (Step_SENS)
Refer to the Average Quiescent Voltage Output Programming
Sens_EXPECTED(TA) should be calculated using the actual measured
values of Sens_T1 and TC_SENS rather than programming target
values.
Sensitivity Drift Through Temperature Range (ΔSens_TC )
Second order sensitivity temperature coefficient effects cause the
magnetic sensitivity, Sens, to drift from its expected value over
the operating ambient temperature range, T_A . The Sensitivity
Drift Through Temperature Range, ∆Sens_TC , is defined as:
∆Sens_TC
=
Sens_TA – Sens_EXPECTED(TA)
Sens_EXPECTED(TA)
× 100%
. (9)
Sensitivity Drift Due to Package Hysteresis (ΔSens_PKG ) Pack-
age stress and relaxation can cause the device sensitivity at T_A =
25°C to change during and after temperature cycling. The sensi-
tivity drift due to package hysteresis, ∆Sens_PKG , is defined as:
∆Sens_PKG
=
Sens_(25°C)2 – Sens_(25°C)1
Sens_(25°C)1
× 100%
,
(10)
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