ACS722
High Accuracy, Galvanically Isolated Current Sensor IC
With Small Footprint SOIC8 Package
FEATURES AND BENEFITS
DESCRIPTION
• Patented integrated digital temperature compensation
circuitry allows for near closed loop accuracy over
temperature in an open loop sensor
• UL60950-1 (ed. 2) certified
□□ Dielectric Strength Voltage = 2.4 kVrms
□□ Basic Isolation Working Voltage = 420 Vpk/297
Vrms
• Industry-leading noise performance with greatly
improved bandwidth through proprietary amplifier and
filter design techniques
• Pin-selectable band width: 80 kHz for high bandwidth
applications or 20 kHz for low noise performance
• 0.65 mΩ primary conductor resistance for low power
loss and high inrush current withstand capability
• Small footprint, low-profile SOIC8 package suitable for
space-constrained applications
• Integrated shield virtually eliminates capacitive coupling
from current conductor to die, greatly suppressing output
noise due to high dv/dt transients
• 3 to 3.6 V, single supply operation
The Allegro™ ACS722 current sensor IC is an economical and
precise solution for AC or DC current sensing in industrial,
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.
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 includes Allegro’s patented digital
temperature compensation, resulting in extremely accurate
performance over temperature. 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 0.65 mΩ typical, providing
low power loss.
Continued on the next page…
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
or other costly isolation techniques.
CB Certif icate Number:
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+
+I P
VCC
ACS722
2
7
IP+
VIOUT
CBYPASS
0.1 µF
IP
3
IP–
BW_SEL
6
–IP
CL
4
IP–
GND
5
Typical Application
ACS722-DS, Rev. 2
The ACS722 outputs an analog
signal, VIOUT , that changes,
proportionally, with the
bidirectional AC or DC primary
sensed current, IP , within
the specified measurement
range. The BW_SEL pin can
be used to select one of the
two bandwidths to optimize the
noise performance. Grounding
the BW_SEL pin puts the part
in the high bandwidth (80 kHz)
mode.
ACS722
High Accuracy, Galvanically Isolated Current Sensor IC
With Small Footprint SOIC8 Package
Features and Benefits (continued)
Description (continued)
• 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
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.
Selection Guide
Part Number
IPR (A)
ACS722LLCTR-05AB-T2
±5
ACS722LLCTR-10AU-T2
10
ACS722LLCTR-10AB-T2
±10
ACS722LLCTR-20AU-T2
20
ACS722LLCTR-20AB-T2
±20
ACS722LLCTR-40AU-T2
40
ACS722LLCTR-40AB-T2
±40
Sens(Typ)
at VCC = 3.3 V
(mV/A)
TA (°C)
Packing1
-40 to 150
Tape and Reel, 3000 pieces per reel
264
132
66
33
1Contact Allegro
2Variant
for additional packing options.
not intended for automotive applications.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
2
ACS722
High Accuracy, Galvanically Isolated Current Sensor IC
With Small Footprint SOIC8 Package
SPECIFICATIONS
Absolute Maximum Ratings
Characteristic
Supply Voltage
Symbol
Rating
Units
VCC
Notes
6
V
Reverse Supply Voltage
VRCC
–0.1
V
Output Voltage
VIOUT
25
V
Reverse Output Voltage
VRIOUT
Operating Ambient Temperature
TA
Range L
–0.1
V
–40 to 150
°C
Junction Temperature
TJ(max)
165
°C
Storage Temperature
Tstg
–65 to 165
°C
Isolation Characteristics
Characteristic
Dielectric Strength Test Voltage
Working Voltage for Basic Isolation
Clearance
Creepage
Symbol
Notes
Rating
Unit
VISO
Agency type-tested for 60 seconds per UL 60950-1 (edition.
2). Production tested at VISO for 1 second, in accordance
with UL 60950-1 (edition. 2).
2400
VRMS
420
VPK or VDC
297
VRMS
VWVBI
Maximum approved working voltage for basic (single)
isolation according UL 60950-1 (edition 2).
Dcl
Minimum distance through air from IP leads to signal leads.
3.9
mm
Dcr
Minimum distance along package body from IP leads to
signal leads.
3.9
mm
Thermal Characteristics
Characteristic
Symbol
Test Conditions*
Value
Units
mm2
Package Thermal Resistance
(Junction to Ambient)
RθJA
Mounted on the Allegro 85-0593 evaluation board with 400
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 722 evaluation board.
5
ºC/W
*Additional thermal information available on the Allegro website.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
3
High Accuracy, Galvanically Isolated Current Sensor IC
With Small Footprint SOIC8 Package
ACS722
VCC
Master Current
Supply
To All Subcircuits
Programming
Control
POR
Hall
Current
Drive
Temperature
Sensor
EEPROM and
Control Logic
Offset
Control
IP+
Sensitivity
Control
IP–
Dynamic Offset
Cancellation
IP+
Tuned
Filter
VIOUT
IP–
BW_SEL
GND
Functional Block Diagram
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
4
ACS722
High Accuracy, Galvanically Isolated Current Sensor IC
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
1, 2
IP+
3, 4
IP–
5
GND
6
BW_SEL
7
VIOUT
8
VCC
Description
Terminals for current being sensed; fused internally
Terminals for current being sensed; fused internally
Signal ground terminal
Terminal for selecting 20 kHz or 80 kHz bandwidth
Analog output signal
Device power supply terminal
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
5
ACS722
High Accuracy, Galvanically Isolated Current Sensor IC
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
Min.
Typ.
Max.
Units
3
3.3
3.6
V
VCC within VCC(min) and VCC(max)
–
9
12
mA
VIOUT to GND
–
–
10
nF
4.7
–
–
kΩ
–
0.65
–
mΩ
–
10
–
G/A
IP = IP(max), TA = 25°C, CL = 1 nF,
BW_SEL tied to GND
–
4
–
μs
IP = IP(max), TA = 25°C, CL = 1 nF,
BW_SEL tied to VCC
–
17.5
–
μs
IP = IP(max), TA = 25°C, CL = 1 nF,
BW_SEL tied to GND
–
1
–
μs
IP = IP(max), TA = 25°C, CL = 1 nF,
BW_SEL tied to VCC
–
5
–
μs
IP = IP(max), TA = 25°C, CL = 1 nF,
BW_SEL tied to GND
–
5
–
μs
IP = IP(max), TA = 25°C, CL = 1 nF,
BW_SEL tied to VCC
–
22.5
–
μs
Small signal –3 dB; CL = 1 nF,
BW_SEL tied to GND
–
80
–
kHz
Small signal –3 dB; CL = 1nF,
BW_SEL tied to VCC
–
20
–
kHz
Input referenced noise density;
TA = 25°C, CL = 1 nF
–
150
–
µA(rms)/
√Hz
Input referenced noise; BWi = 80 kHz,
TA = 25°C, CL = 1 nF
–
42
–
mA(rms)
Input referenced noise; BWi = 20 kHz,
TA = 25°C, CL = 1 nF
–
21
–
mA(rms)
ELIN
Through full range of IP
–
±1
VOH
RL = 4.7 kΩ, TA = 25°C
VCC –
0.33
–
–
V
VOL
RL = 4.7 kΩ, TA = 25°C
–
–
0.33
V
tPO
Output reaches 90% of steady-state
level, TA = 25°C, IP = IPR(max) applied
–
64
–
μs
Supply Voltage
VCC
Supply Current
ICC
Output Capacitance Load
CL
Test Conditions
Output Resistive Load
RL
VIOUT to GND
Primary Conductor Resistance
RIP
TA = 25°C
Magnetic Coupling Factor
CF
Rise Time
Propagation Delay
Response Time
Internal Bandwidth
Noise Density
Noise
Nonlinearity
Saturation Voltage2
Power-On Time
tr
tpd
tRESPONSE
BWi
IND
IN
%
1Device may be operated at higher primary current levels, I , ambient temperatures, T , and internal leadframe temperatures, provided the Maximum Junction TemP
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.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
6
ACS722
High Accuracy, Galvanically Isolated Current Sensor IC
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
Sensitivity
Zero Current Output Voltage
IPR
Sens
VIOUT(Q)
–5
–
5
A
IPR(min) < IP < IPR(max)
–
264
–
mV/A
Bidirectional; IP = 0 A
–
VCC x
0.5
–
V
TA = 25°C to 150°C; measured at IP = IPR(max)
–2
–
2
%
TA = –40°C to 25°C; ; measured at IP = IPR(max)
–
±2.5
–
%
Accuracy Performance
Sensitivity Error
Esens
Offset Voltage1
VOE
Total Output Error2
ETOT
IP = 0 A; TA = 25°C to 150°C
–15
–
15
mV
IP = 0 A; TA = -40°C to 25°C
–
±20
–
mV
IP = IPR(max), TA = 25°C to 150°C
–2.5
–
2.5
%
IP = IPR(max), TA = –40°C to 25°C
–
±3
–
%
Esens_drift
–
±2
–
%
Etot_drift
–
±2
–
%
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift
Total Output Error Lifetime
Drift
1
2
Offset Voltage does not incorporate any error due to external magnetic fields. See section: Impact of External Magnetic Fields.
Percentage of IP , with IP = IPR(max)
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
7
ACS722
High Accuracy, Galvanically Isolated Current Sensor IC
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
Sensitivity
Zero Current Output Voltage
IPR
0
–
10
A
Sens
IPR(min) < IP < IPR(max)
–
264
–
mV/A
VIOUT(Q)
Unidirectional; IP = 0 A
–
VCC x
0.1
–
V
TA = 25°C to 150°C; measured at IP = IPR(max)
–2
–
2
%
TA = –40°C to 25°C; ; measured at IP = IPR(max)
–
±2.5
–
%
Accuracy Performance
Sensitivity Error
Esens
Offset Voltage1
VOE
Total Output Error2
ETOT
IP = 0 A; TA = 25°C to 150°C
–15
–
15
mV
IP = 0 A; TA = -40°C to 25°C
–
±20
–
mV
IP = IPR(max), TA = 25°C to 150°C
–2.5
–
2.5
%
IP = IPR(max), TA = –40°C to 25°C
–
±3
–
%
Esens_drift
–
±2
–
%
Etot_drift
–
±2
–
%
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift
Total Output Error Lifetime
Drift
1
2
Offset Voltage does not incorporate any error due to external magnetic fields. See section: Impact of External Magnetic Fields.
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
Sensitivity
Zero Current Output Voltage
IPR
Sens
VIOUT(Q)
–10
–
10
A
IPR(min) < IP < IPR(max)
–
132
–
mV/A
Bidirectional; IP = 0 A
–
VCC x
0.5
–
V
Accuracy Performance
Sensitivity Error
Esens
Offset Voltage1
VOE
Total Output Error2
ETOT
TA = 25°C to 150°C; measured at IP = IPR(max)
–1.5
–
1.5
%
TA = –40°C to 25°C; ; measured at IP = IPR(max)
–
±2
–
%
IP = 0 A; TA = 25°C to 150°C
–10
–
10
mV
IP = 0 A; TA = -40°C to 25°C
–
±15
–
mV
IP = IPR(max), TA = 25°C to 150°C
–2
–
2
%
IP = IPR(max), TA = –40°C to 25°C
–
±3
–
%
Esens_drift
–
±2
–
%
Etot_drift
–
±2
–
%
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift
Total Output Error Lifetime
Drift
1
2
Offset Voltage does not incorporate any error due to external magnetic fields. See section: Impact of External Magnetic Fields.
Percentage of IP , with IP = IPR(max)
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
8
ACS722
High Accuracy, Galvanically Isolated Current Sensor IC
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
Sensitivity
Zero Current Output Voltage
IPR
0
–
20
A
Sens
IPR(min) < IP < IPR(max)
–
132
–
mV/A
VIOUT(Q)
Unidirectional; IP = 0 A
–
VCC x
0.1
–
V
Accuracy Performance
Sensitivity Error
Esens
Offset Voltage1
VOE
Total Output Error2
ETOT
TA = 25°C to 150°C; measured at IP = IPR(max)
–1.5
–
1.5
%
TA = –40°C to 25°C; ; measured at IP = IPR(max)
–
±2
–
%
IP = 0 A; TA = 25°C to 150°C
–10
–
10
mV
IP = 0 A; TA = -40°C to 25°C
–
±15
–
mV
IP = IPR(max), TA = 25°C to 150°C
–2
–
2
%
IP = IPR(max), TA = –40°C to 25°C
–
±3
–
%
Esens_drift
–
±2
–
%
Etot_drift
–
±2
–
%
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift
Total Output Error Lifetime
Drift
1
2
Offset Voltage does not incorporate any error due to external magnetic fields. See section: Impact of External Magnetic Fields.
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
Sensitivity
Zero Current Output Voltage
IPR
Sens
VIOUT(Q)
–20
–
20
A
IPR(min) < IP < IPR(max)
–
66
–
mV/A
Bidirectional; IP = 0 A
–
VCC x
0.5
–
V
Accuracy Performance
Sensitivity Error
Esens
Offset Voltage1
VOE
Total Output Error2
ETOT
TA = 25°C to 150°C; measured at IP = IPR(max)
–1.5
–
1.5
%
TA = –40°C to 25°C; ; measured at IP = IPR(max)
–
±2
–
%
IP = 0 A; TA = 25°C to 150°C
–10
–
10
mV
IP = 0 A; TA = -40°C to 25°C
–
±15
–
mV
IP = IPR(max), TA = 25°C to 150°C
–2
–
2
%
IP = IPR(max), TA = –40°C to 25°C
–
±3
–
%
Esens_drift
–
±2
–
%
Etot_drift
–
±2
–
%
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift
Total Output Error Lifetime
Drift
1
2
Offset Voltage does not incorporate any error due to external magnetic fields. See section: Impact of External Magnetic Fields.
Percentage of IP , with IP = IPR(max)
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
9
ACS722
High Accuracy, Galvanically Isolated Current Sensor IC
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
Sensitivity
Zero Current Output Voltage
IPR
0
–
40
A
Sens
IPR(min) < IP < IPR(max)
–
66
–
mV/A
VIOUT(Q)
Unidirectional; IP = 0 A
–
VCC x
0.1
–
V
Accuracy Performance
Sensitivity Error
Esens
Offset Voltage1
VOE
Total Output Error2
ETOT
TA = 25°C to 150°C; measured at IP = IPR(max)
–1.5
–
1.5
%
TA = –40°C to 25°C; ; measured at IP = IPR(max)
–
±2
–
%
IP = 0 A; TA = 25°C to 150°C
–10
–
10
mV
IP = 0 A; TA = -40°C to 25°C
–
±15
–
mV
IP = IPR(max), TA = 25°C to 150°C
–2
–
2
%
IP = IPR(max), TA = –40°C to 25°C
–
±3
–
%
Esens_drift
–
±2
–
%
Etot_drift
–
±2
–
%
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift
Total Output Error Lifetime
Drift
1
2
Offset Voltage does not incorporate any error due to external magnetic fields. See section: Impact of External Magnetic Fields.
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
Sensitivity
Zero Current Output Voltage
IPR
Sens
VIOUT(Q)
–40
–
40
A
IPR(min) < IP < IPR(max)
–
33
–
mV/A
Bidirectional; IP = 0 A
–
VCC x
0.5
–
V
Accuracy Performance
Sensitivity Error
Esens
Offset Voltage1
VOE
Total Output Error2
ETOT
TA = 25°C to 150°C; measured at IP = IPR(max)
–1.5
–
1.5
%
TA = –40°C to 25°C; ; measured at IP = IPR(max)
–
±2
–
%
IP = 0 A; TA = 25°C to 150°C
–10
–
10
mV
IP = 0 A; TA = -40°C to 25°C
–
±15
–
mV
IP = IPR(max), TA = 25°C to 150°C
–2
–
2
%
IP = IPR(max), TA = –40°C to 25°C
–
±3
–
%
Esens_drift
–
±2
–
%
Etot_drift
–
±2
–
%
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift
Total Output Error Lifetime
Drift
1
2
Offset Voltage does not incorporate any error due to external magnetic fields. See section: Impact of External Magnetic Fields.
Percentage of IP , with IP = IPR(max)
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
10
High Accuracy, Galvanically Isolated Current Sensor IC
With Small Footprint SOIC8 Package
ACS722
CHARACTERISTIC PERFORMANCE
xLLCTR-5AB Key Parameters
Offset Voltage vs. Temperature
30
1670
20
1660
10
Offset Voltage (mV)
VIOUT(Q) (mV)
Zero Current Output Voltage vs. Temperature
1680
1650
1640
1630
1620
-10
-20
-30
-40
1610
1600
-50
0
0
50
100
-50
-50
150
0
Temperature (ºC)
272
3
270
2
Sensitivity Error (%)
Sensitivity (mV/A)
4
268
266
264
262
260
1
0
-1
-2
-3
-4
0
50
100
150
-50
0
Temperature (ºC)
50
100
150
Temperature (ºC)
Total Error at IPR(max) vs. Temperature
Nonlinearity vs. Temperature
1.00
5
0.80
4
0.60
3
0.40
2
Total Error (%)
Nonlinearity (%)
150
Sensitivity Error vs. Temperature
Sensitivity vs. Temperature
0.20
0.00
-0.20
-0.40
1
0
-1
-2
-0.60
-3
-0.80
-4
-1.00
-50
100
Temperature (ºC)
274
258
-50
50
-5
0
50
100
150
-50
Temperature (ºC)
0
50
100
150
Temperature (ºC)
+3 Sigma
Average
-3 Sigma
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
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11
High Accuracy, Galvanically Isolated Current Sensor IC
With Small Footprint SOIC8 Package
ACS722
xLLCTR-10AB Key Parameters
Offset Voltage vs. Temperature
10
1655
5
Offset Voltage (mV)
VIOUT(Q) (mV)
Zero Current Output Voltage vs. Temperature
1660
1650
1645
1640
0
-5
-10
1635
-15
-50
0
50
100
150
-50
0
Temperature (ºC)
150
100
150
Sensitivity Error vs. Temperature
137
4
136
3
135
2
Sensitivity Error (%)
Sensitivity (mV/A)
100
Temperature (ºC)
Sensitivity vs. Temperature
134
133
132
131
130
1
0
-1
-2
-3
129
-4
-50
0
50
100
150
-50
0
Temperature (ºC)
50
Temperature (ºC)
Total Error at IPR(max) vs. Temperature
Nonlinearity vs. Temperature
1.00
5
0.80
4
0.60
3
0.40
2
Total Error (%)
Nonlinearity (%)
50
0.20
0.00
-0.20
-0.40
-0.60
1
0
-1
-2
-3
-0.80
-4
-1.00
-5
-50
0
50
100
150
-50
Temperature (ºC)
0
50
100
150
Temperature (ºC)
+3 Sigma
Average
-3 Sigma
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
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12
High Accuracy, Galvanically Isolated Current Sensor IC
With Small Footprint SOIC8 Package
ACS722
xLLCTR-10AU Key Parameters
Offset Voltage vs. Temperature
10
335
5
330
0
Offset Voltage (mV)
VIOUT(Q) (mV)
Zero Current Output Voltage vs. Temperature
340
325
320
315
310
305
300
-50
-5
-10
-15
-20
-25
-30
0
50
100
-50
150
0
Temperature (ºC)
5
274
4
100
150
3
Sensitivity Error (%)
Sensitivity (mV/A)
272
270
268
266
264
262
2
1
0
-1
260
-2
258
-3
-4
0
50
100
150
-50
0
Temperature (ºC)
50
Temperature (ºC)
Total Error at IPR(max) vs. Temperature
Nonlinearity vs. Temperature
1.00
5
0.80
4
0.60
3
0.40
2
Total Error (%)
Nonlinearity (%)
150
Sensitivity Error vs. Temperature
Sensitivity vs. Temperature
0.20
0.00
-0.20
-0.40
-0.60
1
0
-1
-2
-3
-0.80
-4
-1.00
-5
-50
100
Temperature (ºC)
276
256
-50
50
0
50
100
150
-50
Temperature (ºC)
0
50
100
150
Temperature (ºC)
+3 Sigma
Average
-3 Sigma
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
13
High Accuracy, Galvanically Isolated Current Sensor IC
With Small Footprint SOIC8 Package
ACS722
xLLCTR-20AB Key Parameters
Offset Voltage vs. Temperature
Zero Current Output Voltage vs. Temperature
1652
1650
1650
1648
1648
Offset Voltage (mV)
VIOUT(Q) (mV)
1652
1646
1644
1642
1640
1646
1644
1642
1640
1638
1638
1636
1636
1634
-50
0
50
100
1634
-50
150
0
Temperature (ºC)
100
150
100
150
Temperature (ºC)
Sensitivity Error vs. Temperature
Sensitivity vs. Temperature
69
5
69
4
68
3
Sensitivity Error (%)
Sensitivity (mV/A)
50
68
67
67
66
66
65
2
1
0
-1
-2
-3
65
-50
-4
0
50
100
150
-50
0
Temperature (ºC)
50
Temperature (ºC)
Total Error at IPR(max) vs. Temperature
Nonlinearity vs. Temperature
1.00
6
0.80
4
0.40
Total Error (%)
Nonlinearity (%)
0.60
0.20
0.00
-0.20
-0.40
-0.60
2
0
-2
-4
-0.80
-1.00
-6
-50
0
50
100
150
-50
Temperature (ºC)
0
50
100
150
Temperature (ºC)
+3 Sigma
Average
-3 Sigma
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
14
High Accuracy, Galvanically Isolated Current Sensor IC
With Small Footprint SOIC8 Package
ACS722
xLLCTR-20AU Key Parameters
Offset Voltage vs. Temperature
10
335
5
Offset Voltage (mV)
VIOUT(Q) (mV)
Zero Current Output Voltage vs. Temperature
340
330
325
320
315
0
-5
-10
-15
310
-50
0
100
50
-20
-50
150
0
Temperature (ºC)
5
138
4
137
3
Sensitivity Error (%)
Sensitivity (mV/A)
150
100
150
Sensitivity Error vs. Temperature
Sensitivity vs. Temperature
136
135
134
133
132
2
1
0
-1
131
-2
130
-3
-4
0
50
100
150
-50
0
Temperature (ºC)
50
Temperature (ºC)
Total Error at IPR(max) vs. Temperature
Nonlinearity vs. Temperature
1.00
5
0.80
4
0.60
3
0.40
2
Total Error (%)
Nonlinearity (%)
100
Temperature (ºC)
139
129
-50
50
0.20
0.00
-0.20
-0.40
1
0
-1
-2
-0.60
-3
-0.80
-4
-1.00
-5
-50
0
50
100
150
-50
Temperature (ºC)
0
50
100
150
Temperature (ºC)
+3 Sigma
Average
-3 Sigma
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
15
High Accuracy, Galvanically Isolated Current Sensor IC
With Small Footprint SOIC8 Package
ACS722
xLLCTR-40AB Key Parameters
Offset Voltage vs. Temperature
Zero Current Output Voltage vs. Temperature
1654
4
1652
2
1650
Offset Voltage (mV)
0
VIOUT(Q) (mV)
1648
1646
1644
1642
1640
-2
-4
-6
-8
-10
1638
-12
1636
-14
1634
-50
0
100
50
-16
-50
150
0
Temperature (ºC)
100
150
100
150
Temperature (ºC)
Sensitivity Error vs. Temperature
Sensitivity vs. Temperature
35
6
5
35
4
Sensitivity Error (%)
Sensitivity (mV/A)
50
34
34
33
3
2
1
0
-1
-2
33
-3
32
-50
-4
0
50
100
150
-50
0
Temperature (ºC)
Temperature (ºC)
Total Error at IPR(max) vs. Temperature
Nonlinearity vs. Temperature
1.00
5
0.80
4
0.60
3
0.40
2
Total Error (%)
Nonlinearity (%)
50
0.20
0.00
-0.20
-0.40
1
0
-1
-2
-0.60
-3
-0.80
-4
-1.00
-5
-50
0
50
100
150
-50
Temperature (ºC)
0
50
100
150
Temperature (ºC)
+3 Sigma
Average
-3 Sigma
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
16
High Accuracy, Galvanically Isolated Current Sensor IC
With Small Footprint SOIC8 Package
ACS722
xLLCTR-40AU Key Parameters
Offset Voltage vs. Temperature
Zero Current Output Voltage vs. Temperature
15
340
10
Offset Voltage (mV)
345
VIOUT(Q) (mV)
335
330
325
320
315
310
-50
5
0
-5
-10
-15
0
100
50
-20
-50
150
0
Temperature (ºC)
5
69
4
68
3
Sensitivity Error (%)
Sensitivity (mV/A)
150
100
150
Sensitivity Error vs. Temperature
Sensitivity vs. Temperature
68
67
67
66
66
65
2
1
0
-1
-2
-3
-4
0
50
100
150
-50
0
Temperature (ºC)
50
Temperature (ºC)
Total Error at IPR(max) vs. Temperature
Nonlinearity vs. Temperature
1.00
5
0.80
4
0.60
3
0.40
2
Total Error (%)
Nonlinearity (%)
100
Temperature (ºC)
69
65
-50
50
0.20
0.00
-0.20
-0.40
1
0
-1
-2
-0.60
-3
-0.80
-4
-1.00
-5
-50
0
50
100
150
-50
Temperature (ºC)
0
50
100
150
Temperature (ºC)
+3 Sigma
Average
-3 Sigma
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
17
High Accuracy, Galvanically Isolated Current Sensor IC
With Small Footprint SOIC8 Package
ACS722
DEFINITIONS OF ACCURACY CHARACTERISTICS
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 amplifier gain is
programmed at the factory to optimize the sensitivity (mV/A) for
the full-scale current of the device.
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 corresponding ETOT versus IP .
Increasing
VIOUT (V)
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:
{ [
ELIN = 1–
VIOUT (IPR(max)) – VIOUT(Q)
2 × VIOUT (IPR(max)/2) – VIOUT(Q)
[{
Accuracy at
25°C Only
IPR(min)
Full Scale IP
Accuracy at
25°C Only
Decreasing
VIOUT (V)
Accuracy Across
Temperature
Figure 1: Output Voltage versus Sensed Current
+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
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)
Sensideal(IP) × IP
IPR(max)
0A
Offset Voltage (VOE)
ETOT(IP) =
+IP (A)
VIOUT(Q)
–IP (A)
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 =
3.3 V translates into VIOUT(Q) = 1.65 V. Variation in VIOUT(Q) can
be attributed to the resolution of the Allegro linear IC quiescent
voltage trim and thermal drift.
Accuracy at
25°C Only
Ideal VIOUT
Accuracy Across
Temperature
× 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.
Accuracy Across
Temperature
× 100 (%)
The Total Output Error incorporates all sources of error and is a
function of IP . At relatively high currents, ETOT will be mostly
–IP
+IP
–ETOT
Figure 2: Total Output Error versus Sensed Current
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
18
ACS722
High Accuracy, Galvanically Isolated Current Sensor IC
With Small Footprint SOIC8 Package
APPLICATION INFORMATION
Impact of External Magnetic Fields
The ACS722 works by sensing the magnetic field created by the
current flowing through the package. However, the sensor cannot
differentiate between fields created by the current flow and external magnetic fields. This means that external magnetic fields can
cause errors in the output of the sensor. Magnetic fields which are
perpendicular to the surface of the package affect the output of
the sensor, as it only senses fields in that one plane. The error in
Amperes can be quantified as:
B
Error(B) =
CF
where B is the strength of the external field perpendicular to the
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 error in mV.
For example, an external field of 1 Gauss will result in around
0.1 A of error. If the ACS722LLCTR-10AB, which has a nominal
sensitivity of 132 mV/A, is being used, that equates to 13.2 mV
of error on the output of the sensor.
Error (mV)
External Field
(Gauss)
Error (A)
0.5
0.05
13.2
1
0.1
26.4
2
0.2
52.8
26.4
5AB
10AB
20AB
40AB
6.6
3.3
1.65
13.2
6.6
3.3
13.2
6.6
Allegro MicroSystems, LLC
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19
High Accuracy, Galvanically Isolated Current Sensor IC
With Small Footprint SOIC8 Package
ACS722
DEFINITIONS OF DYNAMIC RESPONSE CHARACTERISTICS
Power-On Time (tPO)
When the supply is ramped to its operating 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.
V
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.
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.
VIOUT
90% VIOUT
VCC(min.)
t1
t2
tPO
t1= time at which power supply reaches
minimum specified operating voltage
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.
VCC
VCC(typ.)
t2= time at which output voltage settles
within ±10% of its steady state value
under an applied magnetic field
0
t
Figure 3: Power-On Time (tPO)
(%)
90
Primary Current
VIOUT
Rise Time, tr
20
10
0
Propagation Delay, tpd
t
Figure 4: Rise Time (tr) and Propagation Delay (tpd )
(%)
90
Primary Current
VIOUT
Response Time, tRESPONSE
0
t
Figure 5: Response Time (tRESPONSE)
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
20
High Accuracy, Galvanically Isolated Current Sensor IC
With Small Footprint SOIC8 Package
ACS722
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
8°
0°
4.90 ±0.10
1.27
0.65
8
8
1.75
0.25
0.17
3.90 ±0.10
5.60
6.00 ±0.20
A
1.04 REF
1
2
1
1.27
0.40
C
2
PCB Layout Reference View
0.25 BSC
Branded Face
SEATING PLANE
GAUGE PLANE
C
8X
1.75 MAX
0.10 C
0.51
0.31
SEATING
PLANE
NNNNNNN
TPP-AAA
LLLLL
0.25
0.10
1.27 BSC
1
A
Terminal #1 mark area
B
Branding scale and appearance at supplier discretion
C
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
B
Standard Branding Reference View
N = Device part number
T = Device temperature range
P = Package Designator
A = Amperage
L = Lot number
Belly Brand = Country of Origin
Figure 6: Package LC, 8-pin SOICN
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
21
ACS722
High Accuracy, Galvanically Isolated Current Sensor IC
With Small Footprint SOIC8 Package
Revision History
Revision
Revision Date
–
June 10, 2014
1
October 29, 2014
2
April 29, 2015
Description of Revision
Initial release.
Added Magnetic Coupling Factor characteristic and Error Due to External Magnetic Fields section
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:
www.allegromicro.com
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
22