ACS70310 datasheet(9/27 Pages) ALLEGRO

9 / 27 page

Very High Precision, Programmable Linear Hall-Effect Sensor IC

with Reverse Battery Protection and High-Bandwidth (240 kHz)

Analog Output for Core-Based Current Sensing

ACS70310

Allegro MicroSystems

955 Perimeter Road

Manchester, NH 03103-3353 U.S.A.

www.allegromicro.com

Average Fine Sensitivity Programming Step

Size (StepSENS)

This the change is the fine sensitivity parameter per code of sensf

DAC. This value changes depending on SENS_COARSE. Keep

in mind that the over temperature performance of the device is

guaranteed only for the factory programed SENS_COARSE and

its associated SENSPR.

Sensitivity Programming Resolution

This resolution is equal to or less than 1/2 × StepSENS. If the

device is more than 1/2 × StepSENS but less than one StepSENS

away from a desired trim, then an additional step in the correct

direction will yield a resolution less than 1/2 × StepSENS.

Sensitivity Drift Through Temperature Range

(ΔSensTC )

Second-order sensitivity temperature coefficient effects cause the

magnetic sensitivity, Sens, to drift from its expected value over

the operating ambient temperature range (TA). The Sensitivity

Drift Through Temperature Range (∆SensTC) is defined as:

SensTA– SensEXPECTED(TA)

SensEXPECTED(TA)

∆SensTC =

×100% . (4)

Output Voltage Operating Range

The functional range for optimal performance of the device is

between 4.5 to 0.5 V output voltage while VCC = 5 V. The device

can respond to magnetic fields that cause the output to go beyond

these voltages, but parameters may not meet datasheet limits.

Sensitivity Non-Linearity Error (LinERR )

The ACS70310 is designed to provide a linear output in response

to a ramping applied magnetic field. LinERR is valid from 0 G

to ±2000 G input field while within the Output Voltage Operat-

ing Range. Consider two magnetic fields, B1 and B2. Ideally, the

sensitivity of a device is the same for both fields, for a given sup-

ply voltage and temperature. Linearity error is present when there

is a difference between the sensitivities measured at B1 and B2.

Linearity error is calculated separately for the positive SensBPOS2

(LinERRPOS) and negative (LinERRNEG) applied magnetic fields.

Linearity Error (%) is measured and defined as:

SensB(POS,NEG)2

SensB(POS,NEG)1

1–

LinERR(POS,NEG) =

×100%













(5)

where:

|VOUT(Bx) – VOUT(Q)|

SensBx =

(6)

and BPOSx and BNEGx are positive and negative magnetic

fields, with respect to the quiescent voltage output such that

|BPOS2| = 2 × |BPOS1| and |BNEG2| = 2 × |BNEG1|.

Then:

LinERR max(LinERRPOS , LinERRNEG )

(7)

Ratiometry Error (RatERR )

The ACS70310 device features a ratiometric output. This means

that the Quiescent Voltage Output (VOUT(Q)), magnetic sensitiv-

ity, Sens, and Output Voltage Clamp (VCLP(HIGH) and VCLP(LOW))

are proportional to the Supply Voltage (VCC). In other words,

when the supply voltage increases or decreases by a certain

percentage, each characteristic also increases or decreases by the

same percentage. Ratiometry Error is the difference between the

measured change in the supply voltage relative to 5 V, and the

measured change in each characteristic.

The ratiometric error in Quiescent Voltage Output,

RatERRVOUT(Q) (%), for a given supply voltage (VCC) is defined

as:

VOUT(QBI)(VCC)

VCC

1 –

RatERRVOUT(QBI) =

×100% .







VOUT(QBI)(5V)







5 V













(8)

RatERRVOUT(QU) is defined in the same way as RatERRVOUT(QBI)

with a factor of 1/5 multiplied.

This is to scale the ratiometry error of the unidirectional device so

that it can be compared with the bidirectional device.

The ratiometric error in magnetic sensitivity, RatERRSens (%), for

a given Supply Voltage (VCC) is defined as:

Sens(VCC) / Sens(5V)

VCC / 5 V

1–

RatERRSens =

×100% .













(9)

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