ACS724LLC-30AB-T - ALLEGRO MICROSYSTEMS

ACS724

Approximate Scale 1:1

The Allegro™ ACS724 current sensor IC is an economical and

precise solution for AC or DC current sensing in industrial,

automotive, commercial, and communications systems. The

small package is ideal for space constrained applications

while also saving costs due to reduced board area. Typical

applications include motor control, load detection and

management, switched-mode power supplies, and overcurrent

fault protection.

The device consists of a precise, low-offset, linear Hall

sensor circuit with a copper conduction path located near the

surface of the die. Applied current flowing through this copper

conduction path generates a magnetic field which is sensed

by the integrated Hall IC and converted into a proportional

voltage. The current is sensed differentially in order to reject

common mode fields, improving accuracy in magnetically

noisy environments. The inherent device accuracy is optimized

through the close proximity of the magnetic field to the Hall

transducer. A precise, proportional voltage is provided by the

low-offset, chopper-stabilized BiCMOS Hall IC, which is

programmed for accuracy after packaging. The output of the

device has a positive slope when an increasing current flows

through the primary copper conduction path (from pins 1 and

2, to pins 3 and 4), which is the path used for current sensing.

The internal resistance of this conductive path is 1.2 mΩ typical,

providing low power loss.

The terminals of the conductive path are electrically isolated

from the sensor leads (pins 5 through 8). This allows the

ACS724 current sensor IC to be used in high-side current sense

applications without the use of high-side differential amplifiers

or other costly isolation techniques.

ACS724-DS

• Differential Hall sensing rejects common mode fields

• 1.2 mΩ primary conductor resistance for low power loss

and high inrush current withstand capability

• Integrated shield virtually eliminates capacitive

coupling from current conductor to die, greatly

suppressing output noise due to high dv/dt transients

• Industry-leading noise performance with greatly

improved bandwidth through proprietary amplifier and

filter design techniques

• High bandwidth 120kHz analog output for faster

response times in control applications

• Filter pin allows user to filter the output for improved

resolution at lower bandwidth

• Patented integrated digital temperature compensation

circuitry allows for near closed loop accuracy over

temperature in an open loop sensor

• Small footprint, low-profile SOIC8 package suitable for

space-constrained applications

• Filter pin simplifies bandwidth limiting for better

resolution at lower frequencies

Automotive Grade, Galvanically Isolated Current Sensor IC

With Common Mode Field Rejection in a Small Footprint SOIC8 Package

Continued on the next page…

Typical Application

CBYPASS

0.1 µF

1 nF

ACS724

CLOAD

IP+

+IP

–IP

IP+

IP–

VCC

VIOUT

FILTER

GND

The ACS724 outputs an

analog signal, VIOUT , that

changes, proportionally,

with the bidirectional AC

or DC primary sensed

current, IP , within the

specied measurement

range. The FILTER pin

can be used to decrease

the bandwidth in order

to optimize the noise

performance.

FEATURES AND BENEFITS DESCRIPTION

Package: 8-Pin SOIC (suffix LC)

CB Certicate Number:

US-22334-A2-UL

TÜV America

Certificate Number:

U8V 14 11 54214 032

CB 14 11 54214 031

Type

tested

Continued on the next page…

Automotive Grade, Galvanically Isolated Current Sensor IC

With Common Mode Field Rejection in a Small Footprint SOIC8 Package

ACS724

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Selection Guide

Part Number IPR

(A)

Sens(Typ)

at VCC = 5.0 V

(mV/A)

(°C) Packing*

ACS724LLCTR-10AU-T 10 400

-40 to 150 Tape and Reel, 3000 pieces per reel

ACS724LLCTR-10AB-T ±10 200

ACS724LLCTR-20AU-T 20

ACS724LLCTR-20AB-T ±20 100

ACS724LLCTR-30AU-T 30 133

ACS724LLCTR-30AB-T ±30 66

*Contact Allegro for additional packing options.

The ACS724 is provided in a small, low profile surface mount SOIC8

package. The leadframe is plated with 100% matte tin, which is

compatible with standard lead (Pb) free printed circuit board assembly

processes. Internally, the device is Pb-free, except for flip-chip high-

temperature Pb-based solder balls, currently exempt from RoHS.

The device is fully calibrated prior to shipment from the factory.

Features and Benefits (continued)

• 3 to 5.5 V, single supply operation

• Output voltage proportional to AC or DC current

• Factory-trimmed sensitivity and quiescent output voltage for

improved accuracy

• Chopper stabilization results in extremely stable quiescent

output voltage

• Nearly zero magnetic hysteresis

• Ratiometric output from supply voltage

Description (continued)

Automotive Grade, Galvanically Isolated Current Sensor IC

With Common Mode Field Rejection in a Small Footprint SOIC8 Package

ACS724

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Thermal Characteristics

Characteristic Symbol Test Conditions* Value Units

Package Thermal Resistance

(Junction to Ambient) RθJA

Mounted on the Allegro 85-0740 evaluation board with 800

mm2 of 4 oz. copper on each side, connected to pins 1 and

2, and to pins 3 and 4, with thermal vias connecting the

layers. Performance values include the power consumed by

the PCB.

23 ºC/W

Package Thermal Resistance

(Junction to Lead) RθJL Mounted on the Allegro ASEK 724 evaluation board. 5 ºC/W

*Additional thermal information available on the Allegro website.

Isolation Characteristics

Characteristic Symbol Notes Rating Unit

Dielectric Strength Test Voltage VISO

Agency type-tested for 60 seconds per UL standard

60950-1 (edition 2). Production tested at V_ISO for 1

second, in accordance with UL 60950-1 (edition 2).

2400 VRMS

Working Voltage for Basic Isolation VWVBI Maximum approved working voltage for basic (single)

isolation according UL 60950-1 (edition 2)

420 Vpk or VDC

297 Vrms

Clearance Dcl Minimum distance through air from IP leads to signal

leads. 3.9 mm

Creepage Dcr Minimum distance along package body from IP leads to

signal leads. 3.9 mm

Absolute Maximum Ratings

Characteristic Symbol Notes Rating Units

Supply Voltage VCC 6 V

Reverse Supply Voltage VRCC –0.1 V

Output Voltage VIOUT VCC + 0.5 V

Reverse Output Voltage VRIOUT –0.1 V

Operating Ambient Temperature TARange L –40 to 150 °C

Junction Temperature TJ(max) 165 °C

Storage Temperature Tstg –65 to 165 °C

SPECIFICATIONS

Automotive Grade, Galvanically Isolated Current Sensor IC

With Common Mode Field Rejection in a Small Footprint SOIC8 Package

ACS724

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Dynamic Offset

Cancellation

Master Current

Supply Programming

Control

EEPROM and

Control Logic

Offset

Control

Sensitivity

Control

Temperature

Sensor

Hall

Current

Drive

POR

To All Subcircuits

IP+

IP–

VCC

VIOUT

CBYPASS

0.1 µF

FILTER

RF(int)

GND CF

–

Terminal List Table

Number Name Description

1, 2 IP+ Terminals for current being sensed; fused internally

3, 4 IP– Terminals for current being sensed; fused internally

5 GND Signal ground terminal

6 FILTER Terminal for external capacitor that sets bandwidth

7 VIOUT Analog output signal

8 VCC Device power supply terminal

Functional Block Diagram

Package LC, 8-Pin SOICN

Pin-out Diagram

IP+

IP–

VCC

VIOUT

FILTER

GND

Pin-out Diagram and Terminal List Table

Automotive Grade, Galvanically Isolated Current Sensor IC

With Common Mode Field Rejection in a Small Footprint SOIC8 Package

ACS724

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Characteristic Symbol Test Conditions Min. Typ. Max. Unit

Supply Voltage VCC 4.5 – 5.5 V

Supply Current ICC VCC = 5 V, output open – 10 14 mA

Output Capacitance Load CLVIOUT to GND – – 10 nF

Output Resistive Load RLVIOUT to GND 4.7 – – kΩ

Primary Conductor Resistance RIP TA = 25°C – 1.2 – mΩ

Internal Filter Resistance2RF(int) – 1.8 – kΩ

Primary Hall Coupling Factor G1 TA = 25ºC – 11 – G/A

Secondary Hall Coupling Factor G2 TA = 25ºC – 2.8 – G/A

Hall plate Sensitivity Matching Sensmatch TA = 25ºC – ±1 – %

Rise Time trIP = IP(max), TA = 25°C, CL = 1 nF – 3 – μs

Propagation Delay tpd IP = IP(max), TA = 25°C, CL = 1 nF – 2 – μs

Response Time tRESPONSE IP = IP(max), TA = 25°C, CL = 1 nF – 4 – μs

Bandwidth BW Small signal –3 dB; CL = 1 nF – 120 – kHz

Noise Density IND Input referenced noise density;

TA = 25°C, CL = 1 nF – 150 – µA(rms)/

√Hz

Noise INInput referenced noise: CF = 4.7 nF,

CL = 1 nF, BW = 18 kHz, TA = 25°C – 20 – mA(rms)

Nonlinearity ELIN Through full range of IP–1.5 – +1.5 %

Sensitivity Ratiometry Coefficient SENS_RAT_

COEF Vcc = 4.5 to 5.5 V, TA = 25ºC – 1.3 – –

Zero Current Output Ratiometry Coefficient QVO_RAT_

COEF Vcc = 4.5 to 5.5 V, TA = 25ºC – 1 – –

Saturation Voltage3VOH RL = 4.7 kΩ – VCC – 0.3 – V

VOL RL = 4.7 kΩ – 0.3 – V

Power-On Time tPO Output reaches 90% of steady-state

level, TA = 25°C, IP = IPR(max) applied – 80 – μs

Shorted Output to Ground Current Isc(gnd) TA = 25ºC – 3.3 – mA

Shorted Output to VCC Current Isc(vcc) TA = 25ºC – 45 – mA

1Device may be operated at higher primary current levels, IP , ambient temperatures, TA , and internal leadframe temperatures, provided the Maximum Junction Tempera-

ture, TJ(max), is not exceeded.

2RF(int) forms an RC circuit via the FILTER pin.

3The sensor IC will continue to respond to current beyond the range of IP until the high or low saturation voltage; however, the nonlinearity in this region will be worse than

through the rest of the measurement range.

COMMON ELECTRICAL CHARACTERISTICS1: valid through the full range of TA , VCC

= 5.0 V, CF = 0, unless other-

wise specied

Automotive Grade, Galvanically Isolated Current Sensor IC

With Common Mode Field Rejection in a Small Footprint SOIC8 Package

ACS724

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

xLLCTR-10AB PERFORMANCE CHARACTERISTICS: TA Range L, valid at TA = – 40°C to 150°C, VCC = 5.0 V, unless

otherwise specied

Characteristic Symbol Test Conditions Min. Typ.1 Max. Unit

Nominal Performance

Current Sensing Range IPR –10 – 10 A

Sensitivity Sens IPR(min) < IP < IPR(max) – 200 – mV/A

Zero Current Output Voltage VIOUT(Q) Bidirectional; IP = 0 A – VCC ×

0.5 – V

Accuracy Performance

Total Output Error2ETOT

IP = IPR(max); TA = 25°C to 150ºC -2 ±1 2 %

IP = IPR(max); TA = –40°C to 25ºC -6 ±4.5 6

Total Output Error Components3 ETOT = ESENS + 100 x VOE/(Sens x IP)

Sensitivity Error Esens

IP = IPR(max); TA = 25 C to 150 C -1.5 ±1 1.5 %

IP = IPR(max); TA = -40 C to 25 C -5.5 ±4.5 5.5

Offset Voltage VOE

IP = 0 A; TA = 25°C to 150ºC -10 ±6 10 mV

IP = 0 A; TA = –40°C to 25ºC -30 ±8 30

Lifetime Drift Characteristics

Sensitivity Error Lifetime Drift Esens_drift – ±2 – %

Total Output Error Lifetime

Drift Etot_drift – ±2 – %

1 Typical values with +/- are 3 sigma values

2 Percentage of IP

, with IP = IPR(max).

3 A single part will not have both the maximum/minimum sensitivity error and maximum/minimum offset voltage, as that would violate the maximum/minimum total output

error specication. Also, 3 sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section.

xLLCTR-10AU PERFORMANCE CHARACTERISTICS: TA Range L, valid at TA = – 40°C to 150°C, VCC = 5.0 V, unless

otherwise specied

Characteristic Symbol Test Conditions Min. Typ.1 Max. Unit

Nominal Performance

Current Sensing Range IPR 0 – 10 A

Sensitivity Sens IPR(min) < IP < IPR(max) – 400 – mV/A

Zero Current Output Voltage VIOUT(Q) Unidirectional; IP = 0 A – VCC ×

0.1 – V

Accuracy Performance

Total Output Error2ETOT

IP = IPR(max); TA = 25°C to 150ºC –2.5 ±1.5 2.5 %

IP = IPR(max); TA = –40°C to 25ºC –6 ±4.5 6

Total Output Error Components3 ETOT = ESENS + 100 x VOE/(Sens x IP)

Sensitivity Error Esens

IP = IPR(max); TA = 25 C to 150 C –2 ±1 2 %

IP = IPR(max); TA = -40 C to 25 C –5.5 ±4.5 5.5

Offset Voltage VOE

IP = 0 A; TA = 25°C to 150ºC –15 ±7 15 mV

IP = 0 A; TA = –40°C to 25ºC –30 ±13 30

Lifetime Drift Characteristics

Sensitivity Error Lifetime Drift Esens_drift – ±2 – %

Total Output Error Lifetime

Drift Etot_drift – ±2 – %

1 Typical values with +/- are 3 sigma values

2 Percentage of IP

, with IP = IPR(max).

3 A single part will not have both the maximum/minimum sensitivity error and maximum/minimum offset voltage, as that would violate the maximum/minimum total output

error specication. Also, 3 sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section.

Automotive Grade, Galvanically Isolated Current Sensor IC

With Common Mode Field Rejection in a Small Footprint SOIC8 Package

ACS724

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

xLLCTR-20AU PERFORMANCE CHARACTERISTICS: TA Range L, valid at TA = – 40°C to 150°C, VCC = 5.0 V, unless

otherwise specied

Characteristic Symbol Test Conditions Min. Typ.1 Max. Unit

Nominal Performance

Current Sensing Range IPR 0 – 20 A

Sensitivity Sens IPR(min) < IP < IPR(max) – 200 – mV/A

Zero Current Output Voltage VIOUT(Q) Unidirectional; IP = 0 A – VCC ×

0.1 – V

Accuracy Performance

Total Output Error2ETOT

IP = IPR(max); TA = 25°C to 150ºC -2 ±0.7 2 %

IP = IPR(max); TA = –40°C to 25ºC -6 ±4 6

Total Output Error Components3 ETOT = ESENS + 100 x VOE/(Sens x IP)

Sensitivity Error Esens

IP = IPR(max); TA = 25 C to 150 C -1.5 ±0.7 1.5 %

IP = IPR(max); TA = -40 C to 25 C -5.5 ±4 5.5

Offset Voltage VOE

IP = 0 A; TA = 25°C to 150ºC -10 ±6 10 mV

IP = 0 A; TA = –40°C to 25ºC -30 ±8 30

Lifetime Drift Characteristics

Sensitivity Error Lifetime Drift Esens_drift – ±2 – %

Total Output Error Lifetime

Drift Etot_drift – ±2 – %

1 Typical values with +/- are 3 sigma values

2 Percentage of IP

, with IP = IPR(max).

3 A single part will not have both the maximum/minimum sensitivity error and maximum/minimum offset voltage, as that would violate the maximum/minimum total output

error specication. Also, 3 sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section.

xLLCTR-20AB PERFORMANCE CHARACTERISTICS: TA Range L, valid at TA = – 40°C to 150°C, VCC = 5.0 V, unless

otherwise specied

Characteristic Symbol Test Conditions Min. Typ.1 Max. Unit

Nominal Performance

Current Sensing Range IPR –20 – 20 A

Sensitivity Sens IPR(min) < IP < IPR(max) – 100 – mV/A

Zero Current Output Voltage VIOUT(Q) Bidirectional; IP = 0 A – VCC ×

0.5 – V

Accuracy Performance

Total Output Error2ETOT

IP = IPR(max); TA = 25°C to 150ºC -2 ±0.8 2 %

IP = IPR(max); TA = –40°C to 25ºC -6 ±4 6

Total Output Error Components3 ETOT = ESENS + 100 x VOE/(Sens x IP)

Sensitivity Error Esens

IP = IPR(max); TA = 25 C to 150 C -1.5 ±0.6 1.5 %

IP = IPR(max); TA = -40 C to 25 C -5.5 ±4 5.5

Offset Voltage VOE

IP = 0 A; TA = 25°C to 150ºC -10 ±5 10 mV

IP = 0 A; TA = –40°C to 25ºC -30 ±6 30

Lifetime Drift Characteristics

Sensitivity Error Lifetime Drift Esens_drift – ±2 – %

Total Output Error Lifetime

Drift Etot_drift – ±2 – %

1 Typical values with +/- are 3 sigma values

2 Percentage of IP

, with IP = IPR(max).

3 A single part will not have both the maximum/minimum sensitivity error and maximum/minimum offset voltage, as that would violate the maximum/minimum total output

error specication. Also, 3 sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section.

Automotive Grade, Galvanically Isolated Current Sensor IC

With Common Mode Field Rejection in a Small Footprint SOIC8 Package

ACS724

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

xLLCTR-30AU PERFORMANCE CHARACTERISTICS: TA Range L, valid at TA = – 40°C to 150°C, VCC = 5.0 V, unless

otherwise specied

Characteristic Symbol Test Conditions Min. Typ.1 Max. Unit

Nominal Performance

Current Sensing Range IPR 0 – 30 A

Sensitivity Sens IPR(min) < IP < IPR(max) – 133 – mV/A

Zero Current Output Voltage VIOUT(Q) Unidirectional; IP = 0 A – VCC ×

0.1 – V

Accuracy Performance

Total Output Error2ETOT

IP = IPR(max); TA = 25°C to 150ºC -2 ±0.7 2 %

IP = IPR(max); TA = –40°C to 25ºC -6 ±4 6

Total Output Error Components3 ETOT = ESENS + 100 x VOE/(Sens x IP)

Sensitivity Error Esens

IP = IPR(max); TA = 25 C to 150 C -1.5 ±0.7 1.5 %

IP = IPR(max); TA = -40 C to 25 C -5.5 ±4 5.5

Offset Voltage VOE

IP = 0 A; TA = 25°C to 150ºC -10 ±6 10 mV

IP = 0 A; TA = –40°C to 25ºC -30 ±7 30

Lifetime Drift Characteristics

Sensitivity Error Lifetime Drift Esens_drift – ±2 – %

Total Output Error Lifetime

Drift Etot_drift – ±2 – %

1 Typical values with +/- are 3 sigma values

2 Percentage of IP

, with IP = IPR(max).

3 A single part will not have both the maximum/minimum sensitivity error and maximum/minimum offset voltage, as that would violate the maximum/minimum total output

error specication. Also, 3 sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section.

xLLCTR-30AB PERFORMANCE CHARACTERISTICS: TA Range L, valid at TA = – 40°C to 150°C, VCC = 5.0 V, unless

otherwise specied

Characteristic Symbol Test Conditions Min. Typ.1 Max. Unit

Nominal Performance

Current Sensing Range IPR –30 – 30 A

Sensitivity Sens IPR(min) < IP < IPR(max) – 66 – mV/A

Zero Current Output Voltage VIOUT(Q) Bidirectional; IP = 0 A – VCC ×

0.5 – V

Accuracy Performance

Total Output Error2ETOT

IP = IPR(max); TA = 25°C to 150ºC -2 ±0.8 2 %

IP = IPR(max); TA = –40°C to 25ºC -6 ±4 6

Total Output Error Components3 ETOT = ESENS + 100 x VOE/(Sens x IP)

Sensitivity Error Esens

IP = IPR(max); TA = 25 C to 150 C -1.5 ±0.8 1.5 %

IP = IPR(max); TA = -40 C to 25 C -5.5 ±4 5.5

Offset Voltage VOE

IP = 0 A; TA = 25°C to 150ºC -10 ±6 10 mV

IP = 0 A; TA = –40°C to 25ºC -30 ±6 30

Lifetime Drift Characteristics

Sensitivity Error Lifetime Drift Esens_drift – ±2 – %

Total Output Error Lifetime

Drift Etot_drift – ±2 – %

1 Typical values with +/- are 3 sigma values

2 Percentage of IP

, with IP = IPR(max).

3 A single part will not have both the maximum/minimum sensitivity error and maximum/minimum offset voltage, as that would violate the maximum/minimum total output

error specication. Also, 3 sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section.

Automotive Grade, Galvanically Isolated Current Sensor IC

With Common Mode Field Rejection in a Small Footprint SOIC8 Package

ACS724

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

CHARACTERISTIC PERFORMANCE

xLLCTR-10AU

515

510

505

500

495

490

485

-50 050 100 150

Temperature (ºC)

V (mV)

IOUT(Q)

Zero Current Output Voltage vs. Temperature

-15

-10

-5

-50 050 100 150

Temperature (ºC)

Offset Voltage (mV)

Offset Voltage vs. Temperature

415

410

405

400

395

390

385

380

375

-50 050 100 150

Temperature (ºC)

Sensitivity (mV/A)

Sensitivity vs. Temperature

-1

-2

-3

-4

-5

-6

-50 050 100 150

Temperature (ºC)

Sensitivity Error (%)

Sensitivity Error vs. Temperature

1.00

0.80

0.60

0.40

0.20

0.00

-0.20

-0.60

-0.40

-0.80

-1.00

-50 050 100 150

Temperature (ºC)

Nonlinearity (%)

Nonlinearity vs. Temperature

-1

-2

-4

-3

-5

-6

-50 050 100 150

Temperature (ºC)

Total Error (%)

Total Error at I vs. Temperature

PR(max)

Average +3 Sigma -3 Sigma

Automotive Grade, Galvanically Isolated Current Sensor IC

With Common Mode Field Rejection in a Small Footprint SOIC8 Package

ACS724

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

xLLCTR-10AB

2510

2508

2506

2504

2502

2500

2498

2496

2494

2492

-50 050 100 150

Temperature (ºC)

V (mV)

IOUT(Q)

Zero Current Output Voltage vs. Temperature

-2

-4

-6

-8

-50 050 100 150

Temperature (ºC)

Offset Voltage (mV)

Offset Voltage vs. Temperature

206

210

204

208

202

200

198

196

193

192

190

188

-50 050 100 150

Temperature (ºC)

Sensitivity (mV/A)

Sensitivity vs. Temperature

-1

-2

-3

-4

-5

-6

-50 050 100 150

Temperature (ºC)

Sensitivity Error (%)

Sensitivity Error vs. Temperature

1.00

0.80

0.60

0.40

0.20

0.00

-0.20

-0.60

-0.40

-0.80

-1.00

-50 050 100 150

Temperature (ºC)

Nonlinearity (%)

Nonlinearity vs. Temperature

-1

-2

-4

-3

-5

-6

-50 050 100 150

Temperature (ºC)

Total Error (%)

Total Error at I vs. Temperature

PR(max)

Average +3 Sigma -3 Sigma

Automotive Grade, Galvanically Isolated Current Sensor IC

With Common Mode Field Rejection in a Small Footprint SOIC8 Package

ACS724

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

xLLCTR-20AU

500

502

504

506

508

492

494

496

498

490

-50 050 100 150

Temperature (ºC)

V (mV)

IOUT(Q)

Zero Current Output Voltage vs. Temperature

-10

-8

-6

-4

-2

-50 050 100 150

Temperature (ºC)

Offset Voltage (mV)

Offset Voltage vs. Temperature

206

208

204

202

200

198

196

194

192

190

-50 050 100 150

Temperature (ºC)

Sensitivity (mV/A)

Sensitivity vs. Temperature

-1

-2

-3

-4

-5

-50 050 100 150

Temperature (ºC)

Sensitivity Error (%)

Sensitivity Error vs. Temperature

1.00

0.80

0.60

0.40

0.20

0.00

-0.20

-0.60

-0.40

-0.80

-1.00

-50 050 100 150

Temperature (ºC)

Nonlinearity (%)

Nonlinearity vs. Temperature

-1

-2

-4

-3

-5

-50 050 100 150

Temperature (ºC)

Total Error (%)

Total Error at I vs. Temperature

PR(max)

Average +3 Sigma -3 Sigma

Automotive Grade, Galvanically Isolated Current Sensor IC

With Common Mode Field Rejection in a Small Footprint SOIC8 Package

ACS724

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

xLLCTR-20AB

2504

2506

2508

2510

2496

2498

2500

2502

2494

-50 050 100 150

Temperature (ºC)

V (mV)

IOUT(Q)

Zero Current Output Voltage vs. Temperature

-6

-4

-2

-50 050 100 150

Temperature (ºC)

Offset Voltage (mV)

Offset Voltage vs. Temperature

103

104

102

101

100

-50 050 100 150

Temperature (ºC)

Sensitivity (mV/A)

Sensitivity vs. Temperature

-1

-2

-3

-4

-5

-50 050 100 150

Temperature (ºC)

Sensitivity Error (%)

Sensitivity Error vs. Temperature

1.00

0.80

0.60

0.40

0.20

0.00

-0.20

-0.60

-0.40

-0.80

-1.00

-50 050 100 150

Temperature (ºC)

Nonlinearity (%)

Nonlinearity vs. Temperature

-1

-2

-4

-3

-5

-50 050 100 150

Temperature (ºC)

Total Error (%)

Total Error at I vs. Temperature

PR(max)

Average +3 Sigma -3 Sigma

Automotive Grade, Galvanically Isolated Current Sensor IC

With Common Mode Field Rejection in a Small Footprint SOIC8 Package

ACS724

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

xLLCTR-30AU

500

502

504

506

508

492

494

496

498

-50 050 100 150

Temperature (ºC)

V (mV)

IOUT(Q)

Zero Current Output Voltage vs. Temperature

-8

-6

-4

-2

-50 050 100 150

Temperature (ºC)

Offset Voltage (mV)

Offset Voltage vs. Temperature

138

136

134

132

130

128

126

-50 050 100 150

Temperature (ºC)

Sensitivity (mV/A)

Sensitivity vs. Temperature

-1

-2

-3

-4

-5

-50 050 100 150

Temperature (ºC)

Sensitivity Error (%)

Sensitivity Error vs. Temperature

1.00

0.80

0.60

0.40

0.20

0.00

-0.20

-0.60

-0.40

-0.80

-1.00

-50 050 100 150

Temperature (ºC)

Nonlinearity (%)

Nonlinearity vs. Temperature

-1

-2

-4

-3

-5

-50 050 100 150

Temperature (ºC)

Total Error (%)

Total Error at I vs. Temperature

PR(max)

Average +3 Sigma -3 Sigma

Automotive Grade, Galvanically Isolated Current Sensor IC

With Common Mode Field Rejection in a Small Footprint SOIC8 Package

ACS724

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

xLLCTR-30AB

2504

2506

2508

2510

2496

2498

2500

2502

2492

-50 050 100 150

Temperature (ºC)

V (mV)

IOUT(Q)

Zero Current Output Voltage vs. Temperature

2494

-8

-4

-2

-50 050 100 150

Temperature (ºC)

Offset Voltage (mV)

Offset Voltage vs. Temperature

-6

-50 050 100 150

Temperature (ºC)

Sensitivity (mV/A)

Sensitivity vs. Temperature

-1

-2

-3

-4

-5

-50 050 100 150

Temperature (ºC)

Sensitivity Error (%)

Sensitivity Error vs. Temperature

1.00

0.80

0.60

0.40

0.20

0.00

-0.20

-0.60

-0.40

-0.80

-1.00

-50 050 100 150

Temperature (ºC)

Nonlinearity (%)

Nonlinearity vs. Temperature

-1

-2

-4

-3

-5

-50 050 100 150

Temperature (ºC)

Total Error (%)

Total Error at I vs. Temperature

PR(max)

Average +3 Sigma -3 Sigma

Automotive Grade, Galvanically Isolated Current Sensor IC

With Common Mode Field Rejection in a Small Footprint SOIC8 Package

ACS724

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

APPLICATION INFORMATION

Estimating Total Error vs. Sensed Current

The Performance Characteristics tables give distribution (±3

sigma) values for Total Error at IPR(max); however, one often

wants to know what error to expect at a particular current. This

can be estimated by using the distribution data for the compo-

nents of Total Error, Sensitivity Error and Offset Voltage. The

±3 sigma value for Total Error (ETOT) as a function of the sensed

current (IP) is estimated as:

E(I) =

TOTP E+

SENS

2100 × VOE

Sens × IP

()

Here, ESENS and VOE are the ±3 sigma values for those error

terms. If there is an average sensitivity error or average offset

voltage, then the average Total Error is estimated as:

E(I) = E+

TOTP SENS

100 × VOE

Sens × IP

AVGAVG

AVG

The resulting total error will be a sum of ETOT and ETOT_AVG.

Using these equations and the 3 sigma distributions for Sensitiv-

ity Error and Offset Voltage, the Total Error vs. sensed current

(IP) is below for the ACS724LLCTR-20AB. As expected, as one

goes towards zero current, the error in percent goes towards infin-

ity due to division by zero.

-2

-4

-6

-8

0510 15 20

-40ºC + 3σ

-40ºC –3σ

25ºC + 3σ

25ºC –3σ

85ºC + 3σ

85ºC –3σ

Current (A)

Total Error (% of Current Measured)

Figure 1: Predicted Total Error as a Function of the Sensed Current for the ACS724LLCTR-20AB

Automotive Grade, Galvanically Isolated Current Sensor IC

With Common Mode Field Rejection in a Small Footprint SOIC8 Package

ACS724

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Sensitivity (Sens). The change in sensor IC output in response to

a 1 A change through the primary conductor. The sensitivity is the

product of the magnetic circuit sensitivity (G / A) (1 G = 0.1 mT)

and the linear IC amplifier gain (mV/G). The linear IC ampli-

fier gain is programmed at the factory to optimize the sensitivity

(mV/A) for the full-scale current of the device.

Nonlinearity (ELIN). The nonlinearity is a measure of how linear

the output of the sensor IC is over the full current measurement

range. The nonlinearity is calculated as:

LIN

1–

V(I)–V

IOUT PR(max) IOUT(Q)

2•V(I /2) –V

IOUT PR(max) IOUT(Q)

• 100(%)

where VIOUT(IPR(max)) is the output of the sensor IC with the

maximum measurement current flowing through it and

VIOUT(IPR(max)/2) is the output of the sensor IC with half of the

maximum measurement current flowing through it.

Zero Current 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 a bidirectional

device and 0.1 × VCC for a unidirectional device. For example, in

the case of a bidirectional output device, VCC = 5.0 V translates

into VIOUT(Q) = 2.5 V. Variation in VIOUT(Q) can be attributed to

the resolution of the Allegro linear IC quiescent voltage trim and

thermal drift.

Offset Voltage (VOE). The deviation of the device output from

its ideal quiescent value of 0.5 × VCC (bidirectional) or 0.1 × VCC

(unidirectional) due to nonmagnetic causes. To convert this volt-

age to amperes, divide by the device sensitivity, Sens.

Total Output Error (ETOT). The difference between the cur-

rent measurement from the sensor IC and the actual current (IP),

relative to the actual current. This is equivalent to the difference

between the ideal output voltage and the actual output voltage,

divided by the ideal sensitivity, relative to the current flowing

through the primary conduction path:

E(I)

TOTP

V(I)–V (I )

IOUT_idealP IOUT P

Sens (I )•I

idealP P

• 100 (%)

The Total Output Error incorporates all sources of error and is a

function of IP . At relatively high currents, ETOT will be mostly

due to sensitivity error, and at relatively low currents, ETOT will

be mostly due to Offset Voltage (VOE

). In fact, at IP = 0, ETOT

approaches infinity due to the offset. This is illustrated in Figures

1 and 2. Figure 1 shows a distribution of output voltages versus IP

at 25°C and across temperature. Figure 2 shows the correspond-

ing ETOT versus IP .

DEFINITIONS OF ACCURACY CHARACTERISTICS

Figure 1: Output Voltage versus Sensed Current

Figure 2: Total Output Error versus Sensed Current

0 A

Decreasing

IOUT

(V)

Accuracy Across

Temperature

Accuracy Across

Temperature

Accuracy Across

Temperature

Accuracy at

25°C Only

Accuracy at

25°C Only

Accuracy at

25°C Only

Increasing

IOUT

(V)

Ideal V

IOUT

(min)

(max)

(A)

–I

(A)

IOUT(Q)

Full Scale I

+IP

–IP

+ETOT

–ETOT

Across Temperature

25°C Only

Automotive Grade, Galvanically Isolated Current Sensor IC

With Common Mode Field Rejection in a Small Footprint SOIC8 Package

ACS724

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Sensitivity Ratiometry Coefficient (SENS_RAT_COEF). The

coefficient defining how the sensitivity scales with VCC. The

ideal coefficient is 1, meaning the sensitivity scales proportion-

ally with VCC. A 10% increase in VCC results in a 10% increase

in sensitivity. A coefficient of 1.1 means that the sensitivity

increases by 10% more than the ideal proportionality case. This

means that a 10% increase in Vcc results in an 11% increase in

sensitivity. This relationship is described by the following equa-

tion:

Sens(V ) = Sens(5 V)

(V –5 V) • SENS_RAT_COEF

5 V

1 +

This can be rearranged to define the sensitivity ratiometry coef-

ficient as:

Sens(5 V) (V –5 V)

SENS_RAT_COEF = Sens(V )

CC 5 V

–1 •

Zero Current Output Ratiometry Coefficient (QVO_RAT_

COEF). The coefficient defining how the zero current output

voltage scales with VCC. The ideal coefficient is 1, meaning the

output voltage scales proportionally with VCC, always being

equal to VCC/2. A coefficient of 1.1 means that the zero current

output voltage increases by 10% more than the ideal proportion-

ality case. This means that a 10% increase in Vcc results in an

11% increase in the zero current output voltage. This relationship

is described by the following equation:

VIOUTQ(V ) = VIOUTQ(5 V)

(V –5 V) •QVO_RAT_COEF

5 V

1 +

This can be rearranged to define the zero current output ratiom-

etry coefficient as:

VIOUTQ(5 V) (V –5 V)

QVO_RAT_COEF = VIOUTQ(V )

CC 5 V

•

–1

Automotive Grade, Galvanically Isolated Current Sensor IC

With Common Mode Field Rejection in a Small Footprint SOIC8 Package

ACS724

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

DEFINITIONS OF DYNAMIC RESPONSE CHARACTERISTICS

Power-On Time (tPO). When the supply is ramped to its operat-

ing voltage, the device requires a finite time to power its internal

components before responding to an input magnetic field.

Power-On Time, tPO , is defined as the time it takes for the output

voltage to settle within ±10% of its steady state value under an

applied magnetic field, after the power supply has reached its

minimum specified operating voltage, VCC(min), as shown in the

chart at right.

Rise Time (tr). The time interval between a) when the sensor IC

reaches 10% of its full scale value, and b) when it reaches 90%

of its full scale value. The rise time to a step response is used to

derive the bandwidth of the current sensor IC, in which ƒ(–3 dB)

= 0.35 / tr. Both tr and tRESPONSE are detrimentally affected by

eddy current losses observed in the conductive IC ground plane.

Response Time (tRESPONSE). The time interval between a) when

the primary current signal reaches 90% of its final value, and b)

when the device reaches 90% of its output corresponding to the

applied current.

Propagation Delay (tpd

). The propagation delay is measured

as the time interval a) when the primary current signal reaches

20% of its final value, and b) when the device reaches 20% of its

output corresponding to the applied current.

VIOUT

VCC

VCC(min.)

90% VIOUT

t1= time at which power supply reaches

minimum specified operating voltage

t2=

time at which output voltage settles

within ±10% of its steady state value

under an applied magnetic field

t1t2

tPO

(typ.)

Primary Current

VIOUT

(%)

Response Time, tRESPONSE

Primary Current

VIOUT

(%)

Propagation Delay, tpd

Rise Time, tr

Figure 3: Power-On Time (tPO)

Figure 4: Rise Time (tr) and Propagation Delay (tpd)

Figure 5: Response Time (tRESPONSE)

Automotive Grade, Galvanically Isolated Current Sensor IC

With Common Mode Field Rejection in a Small Footprint SOIC8 Package

ACS724

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Figure 6: Package LC, 8-pin SOICN

For Reference Only – Not for Tooling Use

(Reference MS-012AA)

Dimensions in millimeters – NOT TO SCALE

Dimensions exclusive of mold ﬂash, gate burrs, and dambar protrusions

Exact case and lead conﬁguration at supplier discretion within limits shown

SEATING

PLANE

1.27 BSC

Branding scale and appearance at supplier discretion

C0.10

0.25 BSC

1.04 REF

1.75 MAX

4.90 ±0.10

3.90 ±0.10 6.00 ±0.20

0.51

0.31 0.25

0.10

0.25

0.17

1.27

0.40

8°

0°

Standard Branding Reference View

0.65 1.27

5.60

1.75

Branded Face SEATING PLANE

GAUGE PLANE

Terminal #1 mark area

Reference land pattern layout (reference IPC7351 SOIC127P600X175-8M);

all pads a minimum of 0.20 mm from all adjacent pads; adjust as necessary

to meet application process requirements and PCB layout tolerances.

PCB Layout Reference View

N = Device part number

P= Package Designator

T= Device temperature range

A=Amperage

L= Lot number

Belly Brand = Country of Origin

NNNNNNN

PPT-AAA

LLLLL

PACKAGE OUTLING DRAWING

Automotive Grade, Galvanically Isolated Current Sensor IC

With Common Mode Field Rejection in a Small Footprint SOIC8 Package

ACS724

Allegro MicroSystems, LLC

115 Northeast Cutoff

Worcester, Massachusetts 01615-0036 U.S.A.

1.508.853.5000; www.allegromicro.com

Allegro MicroSystems, LLC reserves the right to make, from time to time, such departures from the detail specifications as may be required to

permit improvements in the performance, reliability, or manufacturability of its products. Before placing an order, the user is cautioned to verify that

the information being relied upon is current.

Allegro’s products are not to be used in any devices or systems, including but not limited to life support devices or systems, in which a failure of

Allegro’s product can reasonably be expected to cause bodily harm.

The information included herein is believed to be accurate and reliable. However, Allegro MicroSystems, LLC assumes no responsibility for its

use; nor for any infringement of patents or other rights of third parties which may result from its use.

Document Revision History

Revision Change Pages Responsible Date

0Added Charecteristic Performance graphs and Application Information to

Preliminary draft to create Final draft All A. Latham January 16, 2015