ACS704ELC-015 View Datasheet(PDF) - Allegro MicroSystems
Part Name
Description
MFG CO.
ACS704ELC-015
Allegro MicroSystems
'ACS704ELC-015' PDF : 20 Pages View PDF
ACS704ELC-015
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 prod-
uct of the magnetic circuit sensitivity (G /A) and the linear IC amplifier gain (mV/G). The linear IC amplifier gain is programmed 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 (≈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 (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– (Vout_full-scale amperes – VOUT(Q) )
2 (Vout_half-scale amperes – VOUT(Q) )
where Vout_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 nega-
tive full-scale primary current. The following formula is used to derive symmetry:
Vout_+full-scale amperes – VOUT(Q)
100 VOUT(Q) –Vout_–full-scale amperes
Quiescent output voltage (VOUT(Q)). The output of the sensor when the primary current is zero. For a unipolar supply voltage, it
nominally remains at VCC ⁄ 2. Thus, VCC = 5 V translates into VOUT(Q) = 2.5 V. Variation in VOUT(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 output from its ideal quiescent value of VCC / 2 due to nonmagnetic causes.
To convert this voltage to amperes, divide by the device sensitivity, Sens.
Accuracy (ETOT). The accuracy represents the maximum deviation 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, 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, VOUT(Q), (nominally equal to VCC/2) and sensitivity, Sens, are propor-
tional to its supply voltage, VCC . The following formula is used to derive the ratiometric change in 0 A output voltage, ΔVOUT(Q)RAT (%):
VOUT(Q)VCC / VOUT(Q)5V
100
‰
VCC / 5 V
The ratiometric change in sensitivity, ΔSensRAT (%), is defined as:
SensVCC / Sens5V
100
‰ VCC / 5 V
ACS704ELC015-DS, Rev. 6
11
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 (508) 853-5000
www.allegromicro.com
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