ACS722

High Accuracy, Galvanically Isolated Current Sensor IC

With Small Footprint SOIC8 Package
FEATURES AND BENEFITS DESCRIPTION
• Patented integrated digital temperature compensation The Allegro™ ACS722 current sensor IC is an economical and
circuitry allows for near closed loop accuracy over precise solution for AC or DC current sensing in industrial,
temperature in an open loop sensor commercial, and communications systems. The small package
• UL60950-1 (ed. 2) certified is ideal for space constrained applications while also saving
□□ Dielectric Strength Voltage = 2.4 kVrms costs due to reduced board area. Typical applications include
□□ Basic Isolation Working Voltage = 420 Vpk/297 motor control, load detection and management, switched-mode
Vrms power supplies, and overcurrent fault protection.
• Industry-leading noise performance with greatly
The device consists of a precise, low-offset, linear Hall
improved bandwidth through proprietary amplifier and
sensor circuit with a copper conduction path located near the
filter design techniques
surface of the die. Applied current flowing through this copper
• Pin-selectable band width: 80 kHz for high bandwidth
conduction path generates a magnetic field which is sensed by
applications or 20 kHz for low noise performance
the integrated Hall IC and converted into a proportional voltage.
• 0.65 mΩ primary conductor resistance for low power
Device accuracy is optimized through the close proximity of the
loss and high inrush current withstand capability
magnetic field to the Hall transducer. A precise, proportional
• Small footprint, low-profile SOIC8 package suitable for
voltage is provided by the low-offset, chopper-stabilized
space-constrained applications
BiCMOS Hall IC, which includes Allegro’s patented digital
• Integrated shield virtually eliminates capacitive coupling
temperature compensation, resulting in extremely accurate
from current conductor to die, greatly suppressing output
performance over temperature. The output of the device has
noise due to high dv/dt transients
a positive slope when an increasing current flows through the
• 3 to 3.6 V, single supply operation
primary copper conduction path (from pins 1 and 2, to pins 3
Continued on the next page… and 4), which is the path used for current sensing. The internal
resistance of this conductive path is 0.65 mΩ typical, providing
low power loss.
Package: 8-pin SOIC (suff ix LC) The terminals of the conductive path are electrically isolated
from the sensor leads (pins 5 through 8). This allows the
ACS722 current sensor IC to be used in high-side current sense
applications without the use of high-side differential amplifiers
CB Certif icate Number: or other costly isolation techniques.
US-22334-A1-UL The ACS722 is provided in a small, low profile surface mount
SOIC8 package. The leadframe is plated with 100% matte tin,
Continued on the next page…
Approximate Scale 1:1

1 8
IP+ VCC The ACS722 outputs an analog
+I P signal, VIOUT , that changes,
ACS722 proportionally, with the
7
2 bidirectional AC or DC primary
IP+ VIOUT
sensed current, IP , within
IP CBYPASS the specified measurement
3 6 0.1 µF range. The BW_SEL pin can
IP– BW_SEL be used to select one of the
–IP two bandwidths to optimize the
CL
noise performance. Grounding
4 5
GND the BW_SEL pin puts the part
IP–
in the high bandwidth (80 kHz)
mode.

Typical Application

ACS722-DS, Rev. 2
 High Accuracy, Galvanically Isolated Current Sensor IC
ACS722
With Small Footprint SOIC8 Package

Features and Benefits (continued) Description (continued)

• Output voltage proportional to AC or DC current which is compatible with standard lead (Pb) free printed circuit
• Factory-trimmed sensitivity and quiescent output voltage for board assembly processes. Internally, the device is Pb-free, except
improved accuracy for flip-chip high-temperature Pb-based solder balls, currently
• Chopper stabilization results in extremely stable quiescent exempt from RoHS. The device is fully calibrated prior to shipment
output voltage from the factory.
• Nearly zero magnetic hysteresis
• Ratiometric output from supply voltage

Selection Guide
Sens(Typ)
Part Number IPR (A) at VCC = 3.3 V TA (°C) Packing1
(mV/A)
ACS722LLCTR-05AB-T2 ±5
264
ACS722LLCTR-10AU-T2 10
ACS722LLCTR-10AB-T2 ±10
132
ACS722LLCTR-20AU-T2 20 -40 to 150 Tape and Reel, 3000 pieces per reel
ACS722LLCTR-20AB-T2 ±20
66
ACS722LLCTR-40AU-T2 40
ACS722LLCTR-40AB-T2 ±40 33
1Contact Allegro for additional packing options.
2Variant not intended for automotive applications.

Allegro MicroSystems, LLC 2

115 Northeast Cutoff
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1.508.853.5000; www.allegromicro.com
 High Accuracy, Galvanically Isolated Current Sensor IC
ACS722
With Small Footprint SOIC8 Package

SPECIFICATIONS

Absolute Maximum Ratings

Characteristic Symbol Notes Rating Units
Supply Voltage VCC 6 V
Reverse Supply Voltage VRCC –0.1 V
Output Voltage VIOUT 25 V
Reverse Output Voltage VRIOUT –0.1 V
Operating Ambient Temperature TA Range L –40 to 150 °C
Junction Temperature TJ(max) 165 °C
Storage Temperature Tstg –65 to 165 °C

Isolation Characteristics
Characteristic Symbol Notes Rating Unit
Agency type-tested for 60 seconds per UL 60950-1 (edition.
Dielectric Strength Test Voltage VISO 2). Production tested at VISO for 1 second, in accordance 2400 VRMS
with UL 60950-1 (edition. 2).

420 VPK or VDC

Maximum approved working voltage for basic (single)
Working Voltage for Basic Isolation VWVBI
isolation according UL 60950-1 (edition 2).
297 VRMS

Clearance Dcl Minimum distance through air from IP leads to signal leads. 3.9 mm
Minimum distance along package body from IP leads to
Creepage Dcr 3.9 mm
signal leads.

Thermal Characteristics
Characteristic Symbol Test Conditions* Value Units
Mounted on the Allegro 85-0593 evaluation board with 400 mm2of
Package Thermal Resistance 4 oz. copper on each side, connected to pins 1 and 2, and to pins 3
RθJA 23 ºC/W
(Junction to Ambient) and 4, with thermal vias connecting the layers. Performance values
include the power consumed by the PCB.
Package Thermal Resistance
RθJL Mounted on the Allegro ASEK 722 evaluation board. 5 ºC/W
(Junction to Lead)
*Additional thermal information available on the Allegro website.

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 High Accuracy, Galvanically Isolated Current Sensor IC
ACS722
With Small Footprint SOIC8 Package

VCC

Master Current To All Subcircuits

Supply Programming
Control
POR

Hall
Current Temperature EEPROM and
Drive Sensor Control Logic
Offset
IP+ Control
Sensitivity
IP+ Control
Dynamic Offset
Cancellation

Tuned
VIOUT
Filter

IP–

IP–

BW_SEL GND

Functional Block Diagram

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1.508.853.5000; www.allegromicro.com
 High Accuracy, Galvanically Isolated Current Sensor IC
ACS722
With Small Footprint SOIC8 Package

Pin-out Diagram and Terminal List

IP+ 1 8 VCC
IP+ 2 7 VIOUT
IP– 3 6 BW_SEL
IP– 4 5 GND

Pin-out Diagram

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 BW_SEL Terminal for selecting 20 kHz or 80 kHz bandwidth
7 VIOUT Analog output signal
8 VCC Device power supply terminal

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115 Northeast Cutoff
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1.508.853.5000; www.allegromicro.com
 High Accuracy, Galvanically Isolated Current Sensor IC
ACS722
With Small Footprint SOIC8 Package

COMMON ELECTRICAL CHARACTERISTICS1: valid through the full range of TA = –40°C to 150°C , and at VCC =
3.3 V; unless otherwise specif ied
Characteristic Symbol Test Conditions Min. Typ. Max. Units
Supply Voltage VCC 3 3.3 3.6 V
Supply Current ICC VCC within VCC(min) and VCC(max) – 9 12 mA
Output Capacitance Load CL VIOUT to GND – – 10 nF
Output Resistive Load RL VIOUT to GND 4.7 – – kΩ
Primary Conductor Resistance RIP TA = 25°C – 0.65 – mΩ
Magnetic Coupling Factor CF – 10 – G/A
IP = IP(max), TA = 25°C, CL = 1 nF,
– 4 – μs
BW_SEL tied to GND
Rise Time tr
IP = IP(max), TA = 25°C, CL = 1 nF,
– 17.5 – μs
BW_SEL tied to VCC
IP = IP(max), TA = 25°C, CL = 1 nF,
– 1 – μs
BW_SEL tied to GND
Propagation Delay tpd
IP = IP(max), TA = 25°C, CL = 1 nF,
– 5 – μs
BW_SEL tied to VCC
IP = IP(max), TA = 25°C, CL = 1 nF,
– 5 – μs
BW_SEL tied to GND
Response Time tRESPONSE
IP = IP(max), TA = 25°C, CL = 1 nF,
– 22.5 – μs
BW_SEL tied to VCC
Small signal –3 dB; CL = 1 nF,
– 80 – kHz
BW_SEL tied to GND
Internal Bandwidth BWi
Small signal –3 dB; CL = 1nF,
– 20 – kHz
BW_SEL tied to VCC
Input referenced noise density; µA(rms)/
Noise Density IND – 150 –
TA = 25°C, CL = 1 nF √Hz
Input referenced noise; BWi = 80 kHz,
– 42 – mA(rms)
TA = 25°C, CL = 1 nF
Noise IN
Input referenced noise; BWi = 20 kHz,
– 21 – mA(rms)
TA = 25°C, CL = 1 nF
Nonlinearity ELIN Through full range of IP – ±1 %
VCC –
VOH RL = 4.7 kΩ, TA = 25°C – – V
Saturation Voltage2 0.33
VOL RL = 4.7 kΩ, TA = 25°C – – 0.33 V
Output reaches 90% of steady-state
Power-On Time tPO – 64 – μs
level, TA = 25°C, IP = IPR(max) applied
1Device may be operated at higher primary current levels, I  , ambient temperatures, T  , and internal leadframe temperatures, provided the Maximum Junction Tem-
P A
perature, TJ(max), is not exceeded.
2The sensor IC will continue to respond to current beyond the range of I until the high or low saturation voltage; however, the nonlinearity in this region will be
P
worse than through the rest of the measurement range.

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 High Accuracy, Galvanically Isolated Current Sensor IC
ACS722
With Small Footprint SOIC8 Package

xLLCTR-5AB PERFORMANCE CHARACTERISTICS: TA Range L, valid at TA = – 40°C to 150°C, VCC = 3.3 V, unless oth-
erwise specif ied
Characteristic Symbol Test Conditions Min. Typ. Max. Units
Nominal Performance
Current Sensing Range IPR –5 – 5 A
Sensitivity Sens IPR(min) < IP < IPR(max) – 264 – mV/A
VCC x
Zero Current Output Voltage VIOUT(Q) Bidirectional; IP = 0 A – – V
0.5
Accuracy Performance
TA = 25°C to 150°C; measured at IP = IPR(max) –2 – 2 %
Sensitivity Error Esens
TA = –40°C to 25°C; ; measured at IP = IPR(max) – ±2.5 – %
IP = 0 A; TA = 25°C to 150°C –15 – 15 mV
Offset Voltage1 VOE
IP = 0 A; TA = -40°C to 25°C – ±20 – mV
IP = IPR(max), TA = 25°C to 150°C –2.5 – 2.5 %
Total Output Error2 ETOT
IP = IPR(max), TA = –40°C to 25°C – ±3 – %
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift Esens_drift – ±2 – %
Total Output Error Lifetime
Etot_drift – ±2 – %
Drift
1 Offset Voltage does not incorporate any error due to external magnetic fields. See section: Impact of External Magnetic Fields.
2 Percentage of IP , with IP = IPR(max)

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 High Accuracy, Galvanically Isolated Current Sensor IC
ACS722
With Small Footprint SOIC8 Package

xLLCTR-10AU PERFORMANCE CHARACTERISTICS: TA Range L, valid at TA = – 40°C to 150°C, VCC = 3.3 V, unless
otherwise specif ied
Characteristic Symbol Test Conditions Min. Typ. Max. Units
Nominal Performance
Current Sensing Range IPR 0 – 10 A
Sensitivity Sens IPR(min) < IP < IPR(max) – 264 – mV/A
VCC x
Zero Current Output Voltage VIOUT(Q) Unidirectional; IP = 0 A – – V
0.1
Accuracy Performance
TA = 25°C to 150°C; measured at IP = IPR(max) –2 – 2 %
Sensitivity Error Esens
TA = –40°C to 25°C; ; measured at IP = IPR(max) – ±2.5 – %
IP = 0 A; TA = 25°C to 150°C –15 – 15 mV
Offset Voltage1 VOE
IP = 0 A; TA = -40°C to 25°C – ±20 – mV
IP = IPR(max), TA = 25°C to 150°C –2.5 – 2.5 %
Total Output Error2 ETOT
IP = IPR(max), TA = –40°C to 25°C – ±3 – %
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift Esens_drift – ±2 – %
Total Output Error Lifetime
Etot_drift – ±2 – %
Drift
1 Offset Voltage does not incorporate any error due to external magnetic fields. See section: Impact of External Magnetic Fields.
2 Percentage of IP , with IP = IPR(max)

xLLCTR-10AB PERFORMANCE CHARACTERISTICS: TA Range L, valid at TA = – 40°C to 150°C, VCC = 3.3 V, unless
otherwise specif ied
Characteristic Symbol Test Conditions Min. Typ. Max. Units
Nominal Performance
Current Sensing Range IPR –10 – 10 A
Sensitivity Sens IPR(min) < IP < IPR(max) – 132 – mV/A
VCC x
Zero Current Output Voltage VIOUT(Q) Bidirectional; IP = 0 A – – V
0.5
Accuracy Performance
TA = 25°C to 150°C; measured at IP = IPR(max) –1.5 – 1.5 %
Sensitivity Error Esens
TA = –40°C to 25°C; ; measured at IP = IPR(max) – ±2 – %
IP = 0 A; TA = 25°C to 150°C –10 – 10 mV
Offset Voltage1 VOE
IP = 0 A; TA = -40°C to 25°C – ±15 – mV
IP = IPR(max), TA = 25°C to 150°C –2 – 2 %
Total Output Error2 ETOT
IP = IPR(max), TA = –40°C to 25°C – ±3 – %
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift Esens_drift – ±2 – %
Total Output Error Lifetime
Etot_drift – ±2 – %
Drift
1 Offset Voltage does not incorporate any error due to external magnetic fields. See section: Impact of External Magnetic Fields.
2 Percentage of IP , with IP = IPR(max)

Allegro MicroSystems, LLC 8

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1.508.853.5000; www.allegromicro.com
 High Accuracy, Galvanically Isolated Current Sensor IC
ACS722
With Small Footprint SOIC8 Package

xLLCTR-20AU PERFORMANCE CHARACTERISTICS: TA Range L, valid at TA = – 40°C to 150°C, VCC = 3.3 V, unless
otherwise specif ied
Characteristic Symbol Test Conditions Min. Typ. Max. Units
Nominal Performance
Current Sensing Range IPR 0 – 20 A
Sensitivity Sens IPR(min) < IP < IPR(max) – 132 – mV/A
VCC x
Zero Current Output Voltage VIOUT(Q) Unidirectional; IP = 0 A – – V
0.1
Accuracy Performance
TA = 25°C to 150°C; measured at IP = IPR(max) –1.5 – 1.5 %
Sensitivity Error Esens
TA = –40°C to 25°C; ; measured at IP = IPR(max) – ±2 – %
IP = 0 A; TA = 25°C to 150°C –10 – 10 mV
Offset Voltage1 VOE
IP = 0 A; TA = -40°C to 25°C – ±15 – mV
IP = IPR(max), TA = 25°C to 150°C –2 – 2 %
Total Output Error2 ETOT
IP = IPR(max), TA = –40°C to 25°C – ±3 – %
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift Esens_drift – ±2 – %
Total Output Error Lifetime
Etot_drift – ±2 – %
Drift
1 Offset Voltage does not incorporate any error due to external magnetic fields. See section: Impact of External Magnetic Fields.
2 Percentage of IP , with IP = IPR(max)

xLLCTR-20AB PERFORMANCE CHARACTERISTICS: TA Range L, valid at TA = – 40°C to 150°C, VCC = 3.3 V, unless
otherwise specif ied
Characteristic Symbol Test Conditions Min. Typ. Max. Units
Nominal Performance
Current Sensing Range IPR –20 – 20 A
Sensitivity Sens IPR(min) < IP < IPR(max) – 66 – mV/A
VCC x
Zero Current Output Voltage VIOUT(Q) Bidirectional; IP = 0 A – – V
0.5
Accuracy Performance
TA = 25°C to 150°C; measured at IP = IPR(max) –1.5 – 1.5 %
Sensitivity Error Esens
TA = –40°C to 25°C; ; measured at IP = IPR(max) – ±2 – %
IP = 0 A; TA = 25°C to 150°C –10 – 10 mV
Offset Voltage1 VOE
IP = 0 A; TA = -40°C to 25°C – ±15 – mV
IP = IPR(max), TA = 25°C to 150°C –2 – 2 %
Total Output Error2 ETOT
IP = IPR(max), TA = –40°C to 25°C – ±3 – %
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift Esens_drift – ±2 – %
Total Output Error Lifetime
Etot_drift – ±2 – %
Drift
1 Offset Voltage does not incorporate any error due to external magnetic fields. See section: Impact of External Magnetic Fields.
2 Percentage of IP , with IP = IPR(max)

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1.508.853.5000; www.allegromicro.com
 High Accuracy, Galvanically Isolated Current Sensor IC
ACS722
With Small Footprint SOIC8 Package

xLLCTR-40AU PERFORMANCE CHARACTERISTICS: TA Range L, valid at TA = – 40°C to 150°C, VCC = 3.3 V, unless
otherwise specif ied
Characteristic Symbol Test Conditions Min. Typ. Max. Units
Nominal Performance
Current Sensing Range IPR 0 – 40 A
Sensitivity Sens IPR(min) < IP < IPR(max) – 66 – mV/A
VCC x
Zero Current Output Voltage VIOUT(Q) Unidirectional; IP = 0 A – – V
0.1
Accuracy Performance
TA = 25°C to 150°C; measured at IP = IPR(max) –1.5 – 1.5 %
Sensitivity Error Esens
TA = –40°C to 25°C; ; measured at IP = IPR(max) – ±2 – %
IP = 0 A; TA = 25°C to 150°C –10 – 10 mV
Offset Voltage1 VOE
IP = 0 A; TA = -40°C to 25°C – ±15 – mV
IP = IPR(max), TA = 25°C to 150°C –2 – 2 %
Total Output Error2 ETOT
IP = IPR(max), TA = –40°C to 25°C – ±3 – %
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift Esens_drift – ±2 – %
Total Output Error Lifetime
Etot_drift – ±2 – %
Drift
1 Offset Voltage does not incorporate any error due to external magnetic fields. See section: Impact of External Magnetic Fields.
2 Percentage of IP , with IP = IPR(max)

xLLCTR-40AB PERFORMANCE CHARACTERISTICS: TA Range L, valid at TA = – 40°C to 150°C, VCC = 3.3 V, unless
otherwise specif ied
Characteristic Symbol Test Conditions Min. Typ. Max. Units
Nominal Performance
Current Sensing Range IPR –40 – 40 A
Sensitivity Sens IPR(min) < IP < IPR(max) – 33 – mV/A
VCC x
Zero Current Output Voltage VIOUT(Q) Bidirectional; IP = 0 A – – V
0.5
Accuracy Performance
TA = 25°C to 150°C; measured at IP = IPR(max) –1.5 – 1.5 %
Sensitivity Error Esens
TA = –40°C to 25°C; ; measured at IP = IPR(max) – ±2 – %
IP = 0 A; TA = 25°C to 150°C –10 – 10 mV
Offset Voltage1 VOE
IP = 0 A; TA = -40°C to 25°C – ±15 – mV
IP = IPR(max), TA = 25°C to 150°C –2 – 2 %
Total Output Error2 ETOT
IP = IPR(max), TA = –40°C to 25°C – ±3 – %
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift Esens_drift – ±2 – %
Total Output Error Lifetime
Etot_drift – ±2 – %
Drift
1 Offset Voltage does not incorporate any error due to external magnetic fields. See section: Impact of External Magnetic Fields.
2 Percentage of IP , with IP = IPR(max)

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 High Accuracy, Galvanically Isolated Current Sensor IC
ACS722
With Small Footprint SOIC8 Package
CHARACTERISTIC PERFORMANCE
xLLCTR-5AB Key Parameters
Zero Current Output Voltage vs. Temperature Offset Voltage vs. Temperature
1680 30
1670 20
1660 10

Offset Voltage (mV)

1650 0
VIOUT(Q) (mV)

1640 -10
1630 -20
1620 -30
1610 -40
1600 -50
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

Sensitivity vs. Temperature Sensitivity Error vs. Temperature

274 4
272 3
270 2
Sensitivity Error (%)
Sensitivity (mV/A)

268 1
266 0
264 -1
262 -2
260 -3
258 -4
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

Nonlinearity vs. Temperature Total Error at IPR(max) vs. Temperature

1.00 5
0.80 4
0.60 3
0.40 2
Nonlinearity (%)

Total Error (%)

0.20 1
0.00 0
-0.20 -1
-0.40 -2
-0.60 -3
-0.80 -4
-1.00 -5
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

+3 Sigma Average -3 Sigma

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 High Accuracy, Galvanically Isolated Current Sensor IC
ACS722
With Small Footprint SOIC8 Package

xLLCTR-10AB Key Parameters

Zero Current Output Voltage vs. Temperature Offset Voltage vs. Temperature
1660 10

1655 5

Offset Voltage (mV)

VIOUT(Q) (mV)

1650 0

1645 -5

1640 -10

1635 -15
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

Sensitivity vs. Temperature Sensitivity Error vs. Temperature

137 4
136 3
135 2
Sensitivity Error (%)
Sensitivity (mV/A)

134 1
133 0
132 -1
131 -2
130 -3
129 -4
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

Nonlinearity vs. Temperature Total Error at IPR(max) vs. Temperature

1.00 5
0.80 4
0.60 3
0.40 2
Nonlinearity (%)

Total Error (%)

0.20 1
0.00 0
-0.20 -1
-0.40 -2
-0.60 -3
-0.80 -4
-1.00 -5
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

+3 Sigma Average -3 Sigma

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 High Accuracy, Galvanically Isolated Current Sensor IC
ACS722
With Small Footprint SOIC8 Package

xLLCTR-10AU Key Parameters

Zero Current Output Voltage vs. Temperature Offset Voltage vs. Temperature
340 10
335 5
330 0

Offset Voltage (mV)

325 -5
VIOUT(Q) (mV)

320 -10
315 -15
310 -20
305 -25
300 -30
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

Sensitivity vs. Temperature Sensitivity Error vs. Temperature

276 5
274 4
272 3
Sensitivity Error (%)
Sensitivity (mV/A)

270
2
268
1
266
0
264
262 -1
260 -2
258 -3
256 -4
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

Nonlinearity vs. Temperature Total Error at IPR(max) vs. Temperature

1.00 5
0.80 4
0.60 3
0.40 2
Nonlinearity (%)

Total Error (%)

0.20 1
0.00 0
-0.20 -1
-0.40 -2
-0.60 -3
-0.80 -4
-1.00 -5
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

+3 Sigma Average -3 Sigma

Allegro MicroSystems, LLC 13

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 High Accuracy, Galvanically Isolated Current Sensor IC
ACS722
With Small Footprint SOIC8 Package

xLLCTR-20AB Key Parameters

Zero Current Output Voltage vs. Temperature Offset Voltage vs. Temperature
1652 1652
1650 1650
1648 1648

Offset Voltage (mV)

1646 1646
VIOUT(Q) (mV)

1644 1644
1642 1642
1640 1640
1638 1638
1636 1636
1634 1634
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

Sensitivity vs. Temperature Sensitivity Error vs. Temperature

69 5
69 4
68 3
Sensitivity Error (%)
Sensitivity (mV/A)

68 2
67 1
67 0
66 -1
66 -2
65 -3
65 -4
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

Nonlinearity vs. Temperature Total Error at IPR(max) vs. Temperature

1.00 6
0.80
0.60 4

0.40
Nonlinearity (%)

2
Total Error (%)

0.20
0.00 0
-0.20
-2
-0.40
-0.60
-4
-0.80
-1.00 -6
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

+3 Sigma Average -3 Sigma

Allegro MicroSystems, LLC 14

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 High Accuracy, Galvanically Isolated Current Sensor IC
ACS722
With Small Footprint SOIC8 Package

xLLCTR-20AU Key Parameters

Zero Current Output Voltage vs. Temperature Offset Voltage vs. Temperature
340 10

335 5

Offset Voltage (mV)

330 0
VIOUT(Q) (mV)

325 -5

320 -10

315 -15

310 -20
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

Sensitivity vs. Temperature Sensitivity Error vs. Temperature

139 5
138 4
137 3
Sensitivity Error (%)
Sensitivity (mV/A)

136
2
135
1
134
0
133
132 -1
131 -2
130 -3
129 -4
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

Nonlinearity vs. Temperature Total Error at IPR(max) vs. Temperature

1.00 5
0.80 4
0.60 3
0.40 2
Nonlinearity (%)

Total Error (%)

0.20 1
0.00 0
-0.20 -1
-0.40 -2
-0.60 -3
-0.80 -4
-1.00 -5
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

+3 Sigma Average -3 Sigma

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ACS722
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xLLCTR-40AB Key Parameters

Zero Current Output Voltage vs. Temperature Offset Voltage vs. Temperature
1654 4
1652 2
1650 0

Offset Voltage (mV)

1648 -2
VIOUT(Q) (mV)

1646 -4
1644 -6
1642 -8
1640 -10
1638 -12
1636 -14
1634 -16
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

Sensitivity vs. Temperature Sensitivity Error vs. Temperature

35 6
5
35
4
Sensitivity Error (%)
Sensitivity (mV/A)

34 3
2
34 1
0
33
-1
33 -2
-3
32 -4
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

Nonlinearity vs. Temperature Total Error at IPR(max) vs. Temperature

1.00 5
0.80 4
0.60 3
0.40 2
Nonlinearity (%)

Total Error (%)

0.20 1
0.00 0
-0.20 -1
-0.40 -2
-0.60 -3
-0.80 -4
-1.00 -5
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

+3 Sigma Average -3 Sigma

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 High Accuracy, Galvanically Isolated Current Sensor IC
ACS722
With Small Footprint SOIC8 Package

xLLCTR-40AU Key Parameters

Zero Current Output Voltage vs. Temperature Offset Voltage vs. Temperature
345 15

340 10

Offset Voltage (mV)

335 5
VIOUT(Q) (mV)

330 0

325 -5

320 -10

315 -15

310 -20
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

Sensitivity vs. Temperature Sensitivity Error vs. Temperature

69 5
69 4
68 3
Sensitivity Error (%)
Sensitivity (mV/A)

68 2
67 1
67 0
66 -1
66 -2
65 -3
65 -4
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

Nonlinearity vs. Temperature Total Error at IPR(max) vs. Temperature

1.00 5
0.80 4
0.60 3
0.40 2
Nonlinearity (%)

Total Error (%)

0.20 1
0.00 0
-0.20 -1
-0.40 -2
-0.60 -3
-0.80 -4
-1.00 -5
-50 0 50 100 150 -50 0 50 100 150
Temperature (ºC) Temperature (ºC)

+3 Sigma Average -3 Sigma

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 High Accuracy, Galvanically Isolated Current Sensor IC
ACS722
With Small Footprint SOIC8 Package

DEFINITIONS OF ACCURACY CHARACTERISTICS

Sensitivity (Sens) due to sensitivity error, and at relatively low currents, ETOT will
be mostly due to Offset Voltage (VOE ). In fact, at IP = 0, ETOT
The change in sensor IC output in response to a 1 A change approaches infinity due to the offset. This is illustrated in Figures
through the primary conductor. The sensitivity is the product of 1 and 2. Figure 1 shows a distribution of output voltages versus IP
the magnetic circuit sensitivity (G / A) (1 G = 0.1 mT)and the at 25°C and across temperature. Figure 2 shows the correspond-
linear IC amplifier gain (mV/G). The linear IC amplifier gain is ing ETOT versus IP .
programmed at the factory to optimize the sensitivity (mV/A) for
the full-scale current of the device. Accuracy Across
Temperature
Increasing
Nonlinearity (ELIN) VIOUT (V)
Accuracy at
25°C Only
The nonlinearity is a measure of how linear the output of the sen-
sor IC is over the full current measurement range. The nonlinear- Accuracy Across
Ideal VIOUT

ity is calculated as: Temperature

{ [
ELIN = 1–
VIOUT (IPR(max)) – VIOUT(Q)
2 × VIOUT (IPR(max)/2) – VIOUT(Q) [{ × 100 (%) Accuracy at
25°C Only

IPR(min) +IP (A)

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

maximum measurement current flowing through it and –IP (A)

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

maximum measurement current flowing through it. Full Scale IP
IPR(max)
Zero Current Output Voltage (VIOUT(Q)) 0A

The output of the sensor when the primary current is zero. For
a unipolar supply voltage, it nominally remains at 0.5 × VCC for Accuracy at
25°C Only
a bidirectional device and 0.1 × VCC for a unidirectional device. Accuracy Across
Decreasing
VIOUT (V)
For example, in the case of a bidirectional output device, VCC = Temperature

3.3 V translates into VIOUT(Q) = 1.65 V. Variation in VIOUT(Q) can Figure 1: Output Voltage versus Sensed Current
be attributed to the resolution of the Allegro linear IC quiescent
voltage trim and thermal drift.

Offset Voltage (VOE) +ETOT

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 voltage to amperes, divide
by the device sensitivity, Sens. Across Temperature

Total Output Error (ETOT) 25°C Only

The difference between the current measurement from the sensor

–IP +IP
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:
VIOUT_ideal(IP) – VIOUT(IP)
ETOT(IP) = × 100 (%)
Sensideal(IP) × IP –ETOT

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

function of IP . At relatively high currents, ETOT will be mostly Figure 2: Total Output Error versus Sensed Current

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 High Accuracy, Galvanically Isolated Current Sensor IC
ACS722
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APPLICATION INFORMATION

Impact of External Magnetic Fields surface of the package in Gauss, and CF is the coupling factor in
G/A. Then, multiplying by the sensitivity of the part, Sens, gives
The ACS722 works by sensing the magnetic field created by the the error in mV.
current flowing through the package. However, the sensor cannot
differentiate between fields created by the current flow and exter- For example, an external field of 1 Gauss will result in around
nal magnetic fields. This means that external magnetic fields can 0.1 A of error. If the ACS722LLCTR-10AB, which has a nominal
cause errors in the output of the sensor. Magnetic fields which are sensitivity of 132 mV/A, is being used, that equates to 13.2 mV
perpendicular to the surface of the package affect the output of of error on the output of the sensor.
the sensor, as it only senses fields in that one plane. The error in
External Field Error (mV)
Amperes can be quantified as: Error (A)
(Gauss) 5AB 10AB 20AB 40AB
B
Error(B) = 0.5 0.05 13.2 6.6 3.3 1.65
CF
1 0.1 26.4 13.2 6.6 3.3

where B is the strength of the external field perpendicular to the 2 0.2 52.8 26.4 13.2 6.6

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 High Accuracy, Galvanically Isolated Current Sensor IC
ACS722
With Small Footprint SOIC8 Package

DEFINITIONS OF DYNAMIC RESPONSE CHARACTERISTICS

Power-On Time (tPO) V

VCC
VCC(typ.)
When the supply is ramped to its operating voltage, the device
requires a finite time to power its internal components before 90% VIOUT VIOUT

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 VCC(min.)

applied magnetic field, after the power supply has reached its tPO
t1 t2
minimum specified operating voltage, VCC(min), as shown in the
chart at right. t1= time at which power supply reaches
minimum specified operating voltage

Rise Time (tr) t2= time at which output voltage settles

within ±10% of its steady state value
under an applied magnetic field
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 0
t
Figure 3: Power-On Time (tPO)
value. The rise time to a step response is used to derive the band-
width of the current sensor IC, in which ƒ(–3 dB) = 0.35 / tr. Both
tr and tRESPONSE are detrimentally affected by eddy current losses
(%) Primary Current
observed in the conductive IC ground plane.
90
Propagation Delay (tpd ) VIOUT

The propagation delay is measured as the time interval a) when Rise Time, tr

the primary current signal reaches 20% of its final value, and b) 20
10
when the device reaches 20% of its output corresponding to the 0
Propagation Delay, tpd t
applied current.

Response Time (tRESPONSE) Figure 4: Rise Time (tr) and Propagation Delay (tpd )
The time interval between a) when the primary current signal
reaches 90% of its final value, and b) when the device reaches (%) Primary Current
90% of its output corresponding to the applied current. 90
VIOUT

Response Time, tRESPONSE

0
t

Figure 5: Response Time (tRESPONSE)

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 High Accuracy, Galvanically Isolated Current Sensor IC
ACS722
With Small Footprint SOIC8 Package

Package Outline Drawing

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

4.90 ±0.10 8°
0.65 1.27
0°
8
8
1.75
0.25
0.17

3.90 ±0.10 6.00 ±0.20 5.60

A

1.04 REF

1 2

1.27 1 2
0.40
C PCB Layout Reference View
0.25 BSC
Branded Face
SEATING PLANE
GAUGE PLANE
8X C
1.75 MAX SEATING
0.10 C
PLANE
NNNNNNN
TPP-AAA
LLLLL
0.51 0.25
0.31 0.10
1.27 BSC
1

A Terminal #1 mark area B Standard Branding Reference View

N = Device part number
B Branding scale and appearance at supplier discretion T = Device temperature range
P = Package Designator
C Reference land pattern layout (reference IPC7351 SOIC127P600X175-8M); A = Amperage
all pads a minimum of 0.20 mm from all adjacent pads; adjust as necessary L = Lot number
to meet application process requirements and PCB layout tolerances Belly Brand = Country of Origin

Figure 6: Package LC, 8-pin SOICN

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 High Accuracy, Galvanically Isolated Current Sensor IC
ACS722
With Small Footprint SOIC8 Package

Revision History
Revision Revision Date Description of Revision
– June 10, 2014 Initial release.
1 October 29, 2014 Added Magnetic Coupling Factor characteristic and Error Due to External Magnetic Fields section
2 April 29, 2015 Added Characteristic Performance graphs

Copyright ©2011-2015, Allegro MicroSystems, LLC

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.

For the latest version of this document, visit our website:

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