A1369 Datasheet, PDF (8/22 Pages) Allegro MicroSystems – Customer Programmable Linear Hall-Effect Sensor

A1369
Customer Programmable Linear Hall-Effect Sensor
Optimized for Use in Current Sensing Applications
its quiescent value. This proportionality is specified as the mag-
netic sensitivity, Sens (mV/G), of the device and is defined as:
Sens
=
V_OUT(B+)
B₊
–
–
V_OUT(B–)
B_–
where B+ and B- are two magnetic fields with opposite polarities.
Guaranteed Sensitivity Range. The magnetic sensitivity can be
programmed around its nominal value within the sensitivity range
limits, Sens_(max) and Sens_(min). Refer to the section on guaranteed
quiescent voltage output range for a conceptual explanation.
Average Sensitivity Step Size. Refer to the section on average
quiescent voltage output step size for a conceptual explanation.
Sensitivity Programming Resolution. Refer to the section on
quiescent voltage output programming resolution for a conceptual
explanation.
Sensitivity Temperature Coefficient. The device sensitivity
changes over temperature with respect to its sensitivity tem-
perature coefficient, TC_SENS. TC_SENS is programmed at 85ºC,
and calculated relative to the nominal sensitivity programming
temperature of 25ºC. TC_SENS (%/ºC) is defined as:
( )( ) TC_SENS =
Sens_T2 – Sens_T1
Sens_T1
×
100%
1
T2 – T1
where T1 is the nominal Sens programming temperature of 25ºC,
and T2 is the TC_SENS programming temperature of 85ºC.
The ideal value of sensitivity over temperature, Sens_IDEAL(TA), is
defined as:
Sens_IDEAL(TA) = Sens_T1 × (100% + TC_SENS(T_A – T1))
Guaranteed Sensitivity Temperature Coefficient Range. The
magnetic sensitivity temperature coefficient can be programmed
within its limits of TC_Sens(max) and TC_Sens(min). Refer to the sec-
tion on guaranteed quiescent voltage output range for a concep-
tual explanation.
Average Sensitivity Temperature Coefficient Step Size. Refer
to the section on average quiescent voltage output step size for a
conceptual explanation.
sensitivity temperature coefficient effects cause the magnetic
sensitivity to drift from its ideal value over the operating ambi-
ent temperature, T_A. For purposes of specification, the sensitivity
drift through temperature range, ΔSens_TC, is defined:
DSens_TC –
Sens_TA – Sens_IDEAL(TA)
Sens_IDEAL(TA)
×
100%
Sensitivity Drift Due to Package Hysteresis. Package stress
and relaxation can cause the device sensitivity at T_A = 25ºC to
change during/after temperature cycling. This change in sensitiv-
ity follows a hysteresis curve. For purposes of specification, the
sensitivity drift due to package hysteresis, ΔSens_PKG, is defined:
( ) ^DSensPKG ⁼
Sens_{(25ºV, 2)} – Sens_{(25ºC, 1)}
Sens_{(25ºC, 1)}
× 100%
where Sens_{(25ºC ,1)} is the programmed value of sensitivity at T_A =
25ºC, and Sens_{(25ºC ,2)} is the value of sensitivity at T_A = 25ºC after
temperature cycling T_A up to 85ºC, down to – 40ºC, and back to
up 25ºC.
Linearity Sensitivity Error. The A1369 is designed to provide
linear output in response to a ramping applied magnetic field.
Consider two magnetic fields, B1 and B2. Ideally the sensitivity
of a device is the same for both fields for a given supply voltage
and temperature. Linearity error is present when there is a differ-
ence between the sensitivities measured at B1 and B2.
Linearity Error is calculated separately for the positive (Lin_ERR+)
and negative (Lin_ERR-) applied magnetic fields. Linearity error
(%) is measured and defined as:
( ) ^LinERR+ ⁼
1 – ^SensB++
Sens_B+
× 100%
( ) ^LinERR- ⁼
1 – ^SensB--
Sens_B-
× 100%
Lin_ERR = max(|Lin_ERR+|,|Lin_ERR-|)
where
( ) ^SensBx ⁼
|V – V | _OUTBx
OUT(Q)
D_x
Sensitivity Temperature Coefficient Programming Resolu-
tion. Refer to the section on quiescent voltage output program-
ming resolution for a conceptual explanation.
Sensitivity Drift Through Temperature Range. Second order
and B₊₊, B₊, B_--, and B_- are positive and negative magnetic fields
with respect to the quiescent voltage output such that |B₊₊| > |B₊|
and |B_--| > |B_-|.
Allegro MicroSystems, LLC
8
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com