ACS709LLFTR-35BB-T

 High Bandwidth, Fast Fault Response Current Sensor IC In Thermally Enhanced Package ( 16 Page)

ALLEGRO
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 14 page High Bandwidth, Fast Fault Response Current Sensor ICIn Thermally Enhanced PackageACS70914Allegro MicroSystems, Inc.115 Northeast CutoffWorcester, Massachusetts 01615-0036 U.S.A.1.508.853.5000; www.allegromicro.comSensitivity (Sens). The change in device output in response to a1A change through the primary conductor. The sensitivity is theproduct of the magnetic circuit sensitivity (G /A) and the linearIC amplifier gain (mV/G). The linear IC amplifier gain is pro-grammed at the factory to optimize the sensitivity (mV/A) for thefull-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 shotnoise observed in Hall elements. Dividing the noise (mV) by thesensitivity (mV/A) provides the smallest current that the device isable to resolve.Linearity (ELIN). The degree to which the voltage output fromthe device varies in direct proportion to the primary currentthrough its full-scale amplitude. Nonlinearity in the output can beattributed to the saturation of the flux concentrator approachingthe full-scale current. The following equation is used to derive thelinearity:where VIOUT_full-scale amperes = the output voltage (V) when thesensed current approximates full-scale ±IP .Symmetry (ESYM). The degree to which the absolute voltageoutput from the device varies in proportion to either a positiveor negative full-scale primary current. The following formula isused to derive symmetry:Quiescent output voltage (VIOUT(Q)). The output of the devicewhen the primary current is zero. For a unipolar supply voltage,it nominally remains at 0.5×VCC. For example, in the case of abidirectional output device, VCC = 5 V translates into VIOUT(Q) =2.5 V. Variation in VIOUT(Q) can be attributed to the resolution ofthe 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. Toconvert this voltage to amperes, divide by the device sensitivity,Sens.Accuracy (ETOT). The accuracy represents the maximum devia-tion of the actual output from its ideal value. This is also knownas the total ouput error. The accuracy is illustrated graphically inthe output voltage versus current chart at right. Note that error isdirectly measured during final test at Allegro.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 currentflow including temperature effects. Full-scale current at 25°C. Accuracy of sensing the full-scalecurrent 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, areproportional to its supply voltage, VCC.The following formula isused to derive the ratiometric change in 0 A output voltage,VIOUT(Q)RAT (%).The ratiometric change in sensitivity,SensRAT (%), is defined as:Definitions of Accuracy Characteristics100 1–[{[ {VIOUT_full-scale amperes – VIOUT(Q)2 (VIOUT_1/2 full-scale amperes – VIOUT(Q))100VIOUT_+ full-scale amperes – VIOUT(Q)VIOUT(Q) – VIOUT_–full-scale amperes100VIOUT(Q)VCC / VIOUT(Q)5VVCC / 5 V100SensVCC / Sens5VVCC / 5 VOutput Voltage versus Sensed CurrentAccuracy at 0 A and at Full-Scale CurrentIncreasing VIOUT(V)+IP (A)AccuracyAccuracyAccuracy25°C OnlyAccuracy25°C OnlyAccuracy25°C OnlyAccuracy0 AvrOeTemp eratureAverageVIOUT–IP (A)vrOeTemp eraturevrOeTemp eratureDecreasing VIOUT(V)IP(min)IP(max)Full Scale