ACS716 View Datasheet(PDF) - Allegro MicroSystems
Part Name
Description
MFG CO.
ACS716
Allegro MicroSystems
'ACS716' PDF : 22 Pages View PDF
ACS716
120 kHz Bandwidth, High Voltage Isolation
Current Sensor with Integrated Overcurrent Detection
Definitions of Accuracy Characteristics
Sensitivity (Sens). The change in sensor output in response to a
1A 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 (VNOISE). The product of the linear IC amplifier gain
(mV/G) and the noise floor for the Allegro Hall effect linear
IC. The noise floor is derived from the thermal and shot noise
observed in Hall elements. Dividing the noise (mV) by the sensi-
tivity (mV/A) provides the smallest current that the device is able
to resolve.
Linearity (ELIN). The degree to which the voltage output from
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:
{ [ 100 1–
VIOUT_full-scale amperes – VIOUT(Q)
2 (VIOUT_1/2 full-scale amperes – VIOUT(Q) )
where VIOUT_full-scale amperes = the output voltage (V) when the
sensed current approximates full-scale ±IP .
Symmetry (ESYM). The degree to which the absolute voltage
output from the sensor varies in proportion to either a positive
or negative full-scale primary current. The following formula is
used to derive symmetry:
VIOUT_+ full-scale amperes – VIOUT(Q)
100 VIOUT(Q) – VIOUT_–full-scale amperes
Quiescent output voltage (VIOUT(Q)). The output of the sensor
when the primary current is zero. For a unipolar supply voltage,
it nominally remains at 0.5×VCC. For example, in the case of a
bidirectional output device, VCC = 3.3 V translates into VIOUT(Q)
= 1.65 V. Variation in VIOUT(Q) can be attributed to the resolution
of the Allegro linear IC quiescent voltage trim and thermal drift.
Electrical offset voltage (VOE). The deviation of the device out-
put from its ideal quiescent voltage due to nonmagnetic causes.
To convert this voltage to amperes, divide by the device sensitiv-
ity, Sens.
Accuracy is divided into four areas:
0 A at 25°C. Accuracy of sensing zero current flow at 25°C,
without the effects of temperature.
0 A over Δ temperature. Accuracy of sensing zero current
flow including temperature effects.
Full-scale current at 25°C. Accuracy of sensing the full-scale
current at 25°C, without the effects of temperature.
Full-scale current over Δ temperature. Accuracy of sensing full-
scale current flow including temperature effects.
Ratiometry. The ratiometric feature means that its 0 A output,
VIOUT(Q), (nominally equal to VCC/2) and sensitivity, Sens, are
proportional to its supply voltage, VCC . The following formula is
used to derive the ratiometric change in 0 A output voltage,
VIOUT(Q)RAT (%).
VIOUT(Q)VCC / VIOUT(Q)3.3V
100
VCC / 3.3 (V)
The ratiometric change in sensitivity, SensRAT (%), is defined as:
SensVCC / Sens3.3V
100
VCC / 3.3 (V)
Output Voltage versus Sensed Current
Accuracy at 0 A and at Full-Scale Current
Increasing VIOUT(V)
Accuracy
Over $Temp erature
Accuracy
25°C Only
Accuracy
Over $Temp erature
Average
VIOUT
–IP (A)
IP(min)
Accuracy
25°C Only
0A
Full Scale
IP(max)
+IP (A)
Accuracy (ETOT). The accuracy represents the maximum devia-
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 at right. Note that error is
directly measured during final test at Allegro.
Accuracy
25°C Only
Accuracy
Over $Temp erature
Decreasing VIOUT(V)
Allegro MicroSystems, LLC
19
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
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