ACS754 Allegro MicroSystems, Inc., ACS754 Datasheet - Page 5

• Manufacturer Part Number: ACS754
• Description: Acs754 Current Sensors
• Manufacturer: Allegro MicroSystems, Inc.

ACS754xCB-050
Definitions of Accuracy Characteristics
Sensitivity (Sens). The change in sensor output in response to a
1 A change through the primary conductor. The sensitivity is the
product of the magnetic circuit sensitivity (G / A) and the linear
IC amplifier gain (mV/G). The linear IC amplifier gain is pro-
grammed at the factory to optimize the sensitivity (mV/A) for the
full-scale current of the device.
Noise (V
(mV/G) and the noise floor for the Allegro Hall effect linear IC
(≈1 G). The noise floor is derived from the thermal and shot
noise observed in Hall elements. Dividing the noise (mV) by the
sensitivity (mV/A) provides the smallest current that the device is
able to resolve.
Linearity (E
the sensor varies in direct proportion to the primary current
through its full-scale amplitude. Nonlinearity in the output can be
attributed to the saturation of the flux concentrator approaching
the full-scale current. The following equation is used to derive the
linearity:
where
Symmetry (E
output from the sensor varies in proportion to either a positive
or negative full-scale primary current. The following equation is
used to derive symmetry:
∆ gain = the gain variation as a function of temperature
changes from 25ºC,
% sat = the percentage of saturation of the flux concentra-
tor, which becomes significant as the current being sensed
approaches full-scale ±I
V
current approximates full-scale ±I
100 1–
IOUT_full-scale amperes
[ {
NOISE
100
Δ gain × % sat (
LIN
SYM

). The product of the linear IC amplifier gain
V
V
). The degree to which the voltage output from
2 (V
IOUT
IOUT(Q)
). The degree to which the absolute voltage
IOUT
_+ full-scale amperes – V
= the output voltage (V) when the sensed
– V
_half-scale amperes – V
V
P
IOUT
IOUT
, and
_–full-scale amperes
_full-scale amperes – V
P
with High Voltage Isolation and a Low-Resistance Current Conductor
.
IOUT(Q)
IOUT(Q)

Fully Integrated, Hall Effect-Based Linear Current Sensor
IOUT(Q)
)
)
[ {
Quiescent output voltage (V
when the primary current is zero. For a unipolar supply voltage,
it nominally remains at V
V
olution of the Allegro linear IC quiescent voltage trim, magnetic
hysteresis, and thermal drift.
Electrical offset voltage (V
put from its ideal quiescent value of V
causes.
Magnetic offset error (I
the residual magnetism (remnant field) of the core material. The
magnetic offset error is highest when the magnetic circuit has
been saturated, usually when the device has been subjected to a
full-scale or high-current overload condition. The magnetic offset
is largely dependent on the material used as a flux concentrator.
The larger magnetic offsets are observed at the lower operating
temperatures.
Accuracy (E
tion of the actual output from its ideal value. This is also known
as the total ouput error. The accuracy is illustrated graphically in
the output voltage versus current chart on the following page.
Accuracy is divided into four areas:
• 0 A at 25°C. Accuracy of sensing zero current flow at 25°C,
• 0 A over Δ temperature. Accuracy of sensing zero current
• Full-scale current at 25°C. Accuracy of sensing the full-scale
• Full-scale current over Δ temperature. Accuracy of sensing full-
IOUT(Q)
without the effects of temperature.
flow including temperature effects.
current at 25°C, without the effects of temperature.
scale current flow including temperature effects.
= 2.5 V. Variation in V
TOT
). The accuracy represents the maximum devia-
CC
ERROM
115 Northeast Cutoff
1.508.853.5000; www.allegromicro.com
Allegro MicroSystems, Inc.
Worcester, Massachusetts 01615-0036 U.S.A.
OE
⁄ 2. Thus, V
IOUT(Q)
). The deviation of the device out-
OUT(Q)
). The magnetic offset is due to
). The output of the sensor
CC
can be attributed to the res-
CC
⁄ 2 due to nonmagnetic
= 5 V translates into
5