ACS704 Allegro Micro Systems, Inc., ACS704 Datasheet - Page 11

• Manufacturer Part Number: ACS704
• Manufacturer: Allegro Micro Systems, Inc.

Sensitivity (Sens). The change in sensor output in response to a 1 A 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 (V
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
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 V
Symmetry (E
tive full-scale primary current. The following formula is used to derive symmetry:
Quiescent output voltage (V
nominally remains at V
of the Allegro linear IC quiescent voltage trim and thermal drift.
Electrical offset voltage (V
To convert this voltage to amperes, divide by the device sensitivity, Sens.
Accuracy (E
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, V
tional to its supply voltage, V
The ratiometric change in sensitivity, ΔSens
ACS704ELC005-DS, Rev. 7
out_full-scale amperes
NOISE
LIN
TOT
SYM
). The product of the linear IC amplifier gain (mV/G) and the noise floor for the Allegro Hall effect linear IC (≈1 G).
): The degree to which the voltage output from the sensor varies in direct proportion to the primary current through its
). The accuracy represents the maximum deviation of the actual output from its ideal value. This is also known as the
). The degree to which the absolute voltage output from the sensor varies in proportion to either a positive or nega-
CC
= the output voltage (V) when the sensed current approximates full-scale ±I
⁄ 2. Thus, V
OE
CC
OUT(Q)
). The deviation of the device output from its ideal quiescent value of V
. The following formula is used to derive the ratiometric change in 0 A output voltage, ΔV
). The output of the sensor when the primary current is zero. For a unipolar supply voltage, it
Definitions of Accuracy Characteristics
Definitions of Accuracy Characteristics
CC
= 5 V translates into V
100 1–
RAT
ACS704ELC-005
[ {
100
(%), is defined as:
2 (V out_half-scale amperes – V
(
100
V out_+full-scale amperes – V
V
V out_full-scale amperes – V
OUT(Q)
100
V
OUT(Q)VCC
–V out_–full-scale amperes
Sens
V
OUT(Q)
OUT(Q)
VCC
V
CC
CC
/ 5 V
/ V
/ Sens
/ 5 V
= 2.5 V. Variation in V
, (nominally equal to V
OUT(Q)5V
5V
OUT(Q)
OUT(Q)
OUT(Q)
)
)
[ {
115 Northeast Cutoff, Box 15036
Worcester, Massachusetts 01615-0036 [phone]
www.allegromicro.com
OUT(Q)
CC
/2) and sensitivity, Sens, are propor-
can be attributed to the resolution
P
CC
.
/ 2 due to nonmagnetic causes.
OUT(Q)RAT
(%):
11