ACS724 Datasheet

ACS724
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
FEATURES AND BENEFITS
DESCRIPTION
• 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 120 kHz 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
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.
Continued on the next page…
Package: 8-Pin SOIC (suffix LC)
pe d
Ty ste
te
TÜV America
Certificate Number:
U8V 14 11 54214 032
CB 14 11 54214 031
CB Certificate Number:
US-22334-A2-UL
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.
Approximate Scale 1:1
1
+IP
2
IP+
IP+
VCC
–IP
4
IP–
IP–
8
ACS724
VIOUT
IP
3
Continued on the next page…
FILTER
GND
7
CBYPASS
0.1 µF
6
5
CF
1 nF
Typical Application
ACS724-DS, Rev. 3
CLOAD
The ACS724 outputs an
analog signal, VIOUT , that
changes proportionally
with the bidirectional AC
or DC primary sensed
current, IP , within the
specified measurement
range. The FILTER pin
can be used to decrease
the bandwidth in order
to optimize the noise
performance.
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
ACS724
Features and Benefits (continued)
Description (continued)
• 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
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.
Selection Guide
Part Number
IPR
(A)
Sens(Typ)
at VCC = 5 V
(mV/A)
ACS724LLCTR-10AU-T
10
400
ACS724LLCTR-10AB-T
±10
ACS724LLCTR-20AU-T
20
TA
(°C)
Packing*
-40 to 150
Tape and Reel, 3000 pieces per reel
200
ACS724LLCTR-20AB-T
±20
100
ACS724LLCTR-30AU-T
30
133
ACS724LLCTR-30AB-T
±30
66
ACS724LLCTR-50AB-T
±50
40
*Contact Allegro for additional packing options.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
2
ACS724
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
SPECIFICATIONS
Absolute Maximum Ratings
Characteristic
Supply Voltage
Symbol
Notes
VCC
Rating
Units
6
V
Reverse Supply Voltage
VRCC
–0.1
V
Output Voltage
VIOUT
VCC + 0.5
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
Rating
Unit
2400
VRMS
Isolation Characteristics
Characteristic
Symbol
Notes
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).
VWVBI
Maximum approved working voltage for basic (single)
isolation according to UL 60950-1 (edition 2)
Clearance
Dcl
Creepage
Dcr
Dielectric Strength Test Voltage
Working Voltage for Basic Isolation
420
Vpk or VDC
297
Vrms
Minimum distance through air from IP leads to signal
leads.
3.9
mm
Minimum distance along package body from IP leads to
signal leads.
3.9
mm
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 ASEK724 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
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
ACS724
VCC
VCC
Master Current
Supply
To All Subcircuits
Programming
Control
POR
Hall
Current
Drive
Temperature
Sensor
CBYPASS
0.1 µF
EEPROM and
Control Logic
Offset
Control
IP+
Sensitivity
Control
Dynamic Offset
Cancellation
IP+
IP–
+
–
RF(int)
+
–
VIOUT
IP–
GND
CF
FILTER
Functional Block Diagram
Pin-Out Diagram and Terminal List Table
Terminal List Table
IP+
1
8
VCC
IP+
2
7
VIOUT
IP–
3
6
FILTER
IP–
4
5
GND
Package LC, 8-Pin SOICN
Pin-Out Diagram
Number
Name
1, 2
IP+
Description
Terminals for current being sensed; fused internally
3, 4
IP–
5
GND
Terminals for current being sensed; fused internally
6
FILTER
Terminal for external capacitor that sets bandwidth
7
VIOUT
Analog output signal
8
VCC
Signal ground terminal
Device power supply terminal
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
4
ACS724
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
COMMON ELECTRICAL CHARACTERISTICS1: valid through the full range of TA , VCC = 5 V, CF = 0, unless otherwise specified
Characteristic
Symbol
Test Conditions
Min.
Typ.
Max.
Unit
4.5
–
5.5
V
–
10
14
mA
Supply Voltage
VCC
Supply Current
ICC
VCC = 5 V, output open
Output Capacitance Load
CL
VIOUT to GND
–
–
10
nF
Output Resistive Load
RL
VIOUT to GND
4.7
–
–
kΩ
RIP
TA = 25°C
–
1.2
–
mΩ
–
1.8
–
kΩ
Primary Conductor Resistance
Internal Filter Resistance2
Primary Hall Coupling Factor
Secondary Hall Coupling Factor
Hall Plate Sensitivity Matching
RF(int)
G1
TA = 25ºC
–
11
–
G/A
G2
TA = 25ºC
–
2.8
–
G/A
Sensmatch
TA = 25ºC
–
±1
–
%
Rise Time
tr
IP = 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
IN
Input-referenced noise: CF = 4.7 nF,
CL = 1 nF, BW = 18 kHz, TA = 25°C
–
20
–
mA(rms)
–1.5
–
+1.5
%
Nonlinearity
ELIN
Through full range of IP
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
–
–
VOH
RL = 4.7 kΩ
–
VCC – 0.3
–
V
VOL
RL = 4.7 kΩ
–
0.3
–
V
tPO
Output reaches 90% of steady-state
level, TA = 25°C, IP = IPR(max) applied
–
80
–
μs
Saturation Voltage3
Power-On Time
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 Temperature, TJ(max), is not exceeded.
2R
F(int) forms an RC circuit via the FILTER pin.
3The 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 worse than
P
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
5
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
ACS724
xLLCTR-10AU PERFORMANCE CHARACTERISTICS: TA Range L, valid at TA = – 40°C to 150°C, VCC = 5 V, unless other-
wise specified
Characteristic
Symbol
Test Conditions
Min.
Typ.1
Max.
Unit
Nominal Performance
Current-Sensing Range
Sensitivity
Zero-Current Output Voltage
IPR
Sens
VIOUT(Q)
0
–
10
A
IPR(min) < IP < IPR(max)
–
400
–
mV/A
Unidirectional, IP = 0 A
–
VCC ×
0.1
–
V
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
%
IP = IPR(max), TA = 25°C to 150°C
–2
±1
2
%
Accuracy Performance
Total Output Error2
ETOT
Total Output Error Components3 ETOT = ESENS + 100 × VOE/(Sens × IP)
Sensitivity Error
Offset Voltage
Esens
VOE
IP = IPR(max), TA = –40°C to 25°C
–5.5
±4.5
5.5
%
IP = 0 A, TA = 25°C to 150ºC
–15
±7
15
mV
IP = 0 A, TA = –40°C to 25ºC
–30
±13
30
mV
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift
Esens_drift
–3
±1
3
%
Total Output Error Lifetime Drift
Etot_drift
–3
±1
3
%
1 Typical
values with +/- are 3 sigma values
2 Percentage of I , with I = I
P P
PR(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 specification. Also, 3 sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
6
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
ACS724
xLLCTR-10AB PERFORMANCE CHARACTERISTICS: TA Range L, valid at TA = – 40°C to 150°C, VCC = 5 V, unless other-
wise specified
Characteristic
Symbol
Test Conditions
Min.
Typ.1
Max.
Unit
Nominal Performance
Current-Sensing Range
IPR
–10
–
10
A
Sens
IPR(min) < IP < IPR(max)
–
200
–
mV/A
VIOUT(Q)
Bidirectional, IP = 0 A
–
VCC ×
0.5
–
V
IP = IPR(max), TA = 25°C to 150ºC
-2
±1
2
%
IP = IPR(max), TA = –40°C to 25ºC
-6
±4.5
6
%
IP = IPR(max), TA = 25°C to 150°C
-1.5
±1
1.5
%
Sensitivity
Zero-Current Output Voltage
Accuracy Performance
Total Output Error2
Total Output Error
ETOT
Components3
Sensitivity Error
Offset Voltage
ETOT = ESENS + 100 × VOE/(Sens × IP)
Esens
VOE
IP = IPR(max), TA = –40°C to 25°C
-5.5
±4.5
5.5
%
IP = 0 A, TA = 25°C to 150ºC
-10
±6
10
mV
IP = 0 A, TA = –40°C to 25ºC
-30
±8
30
mV
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift
Esens_drift
–3
±1
3
%
Total Output Error Lifetime Drift
Etot_drift
–3
±1
3
%
1 Typical
values with +/- are 3 sigma values
2 Percentage of I , with I = I
P P
PR(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 specification. Also, 3 sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
7
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
ACS724
xLLCTR-20AU PERFORMANCE CHARACTERISTICS: TA Range L, valid at TA = – 40°C to 150°C, VCC = 5 V, unless other-
wise specified
Characteristic
Symbol
Test Conditions
Min.
Typ.1
Max.
Unit
Nominal Performance
Current-Sensing Range
IPR
Sensitivity
Sens
Zero-Current Output Voltage
VIOUT(Q)
0
–
20
A
IPR(min) < IP < IPR(max)
–
200
–
mV/A
Unidirectional, IP = 0 A
–
VCC ×
0.1
–
V
IP = IPR(max), TA = 25°C to 150ºC
-2
±0.7
2
%
IP = IPR(max), TA = –40°C to 25ºC
-6
±4
6
%
IP = IPR(max), TA = 25°C to 150°C
-1.5
±0.7
1.5
%
Accuracy Performance
Total Output Error2
Total Output Error
ETOT
Components3
Sensitivity Error
Offset Voltage
ETOT = ESENS + 100 × VOE/(Sens × IP)
Esens
VOE
IP = IPR(max), TA = –40°C to 25°C
-5.5
±4
5.5
%
IP = 0 A, TA = 25°C to 150ºC
-10
±6
10
mV
IP = 0 A, TA = –40°C to 25ºC
-30
±8
30
mV
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift
Esens_drift
–3
±1
3
%
Total Output Error Lifetime Drift
Etot_drift
–3
±1
3
%
1 Typical
values with +/- are 3 sigma values
2 Percentage of I , with I = I
P P
PR(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 specification. Also, 3 sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
8
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
ACS724
xLLCTR-20AB PERFORMANCE CHARACTERISTICS: TA Range L, valid at TA = – 40°C to 150°C, VCC = 5 V, unless other-
wise specified
Characteristic
Symbol
Test Conditions
Min.
Typ.1
Max.
Unit
Nominal Performance
Current-Sensing Range
IPR
–20
–
20
A
Sens
IPR(min) < IP < IPR(max)
–
100
–
mV/A
VIOUT(Q)
Bidirectional, IP = 0 A
–
VCC ×
0.5
–
V
IP = IPR(max), TA = 25°C to 150ºC
-2
±0.8
2
%
IP = IPR(max), TA = –40°C to 25ºC
-6
±4
6
%
IP = IPR(max), TA = 25°C to 150°C
-1.5
±0.6
1.5
%
Sensitivity
Zero-Current Output Voltage
Accuracy Performance
Total Output Error2
Total Output Error
ETOT
Components3
Sensitivity Error
Offset Voltage
ETOT = ESENS + 100 × VOE/(Sens × IP)
Esens
VOE
IP = IPR(max), TA = –40°C to 25°C
-5.5
±4
5.5
%
IP = 0 A, TA = 25°C to 150ºC
-10
±5
10
mV
IP = 0 A, TA = –40°C to 25ºC
-30
±6
30
mV
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift
Esens_drift
–3
±1
3
%
Total Output Error Lifetime Drift
Etot_drift
–3
±1
3
%
1 Typical
values with +/- are 3 sigma values
2 Percentage of I , with I = I
P P
PR(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 specification. Also, 3 sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
9
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
ACS724
xLLCTR-30AU PERFORMANCE CHARACTERISTICS: TA Range L, valid at TA = – 40°C to 150°C, VCC = 5 V, unless other-
wise specified
Characteristic
Symbol
Test Conditions
Min.
Typ.1
Max.
Unit
Nominal Performance
Current-Sensing Range
IPR
Sensitivity
Sens
Zero-Current Output Voltage
VIOUT(Q)
0
–
30
A
IPR(min) < IP < IPR(max)
–
133
–
mV/A
Unidirectional, IP = 0 A
–
VCC ×
0.1
–
V
IP = IPR(max), TA = 25°C to 150ºC
-2
±0.7
2
%
IP = IPR(max), TA = –40°C to 25ºC
-6
±4
6
%
IP = IPR(max), TA = 25°C to 150°C
-1.5
±0.7
1.5
%
Accuracy Performance
Total Output Error2
Total Output Error
ETOT
Components3
Sensitivity Error
Offset Voltage
ETOT = ESENS + 100 × VOE/(Sens × IP)
Esens
VOE
IP = IPR(max), TA = –40°C to 25°C
-5.5
±4
5.5
%
IP = 0 A, TA = 25°C to 150ºC
-10
±6
10
mV
IP = 0 A, TA = –40°C to 25ºC
-30
±7
30
mV
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift
Esens_drift
–3
±1
3
%
Total Output Error Lifetime Drift
Etot_drift
–3
±1
3
%
1 Typical
values with +/- are 3 sigma values
2 Percentage of I , with I = I
P P
PR(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 specification. Also, 3 sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
10
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
ACS724
xLLCTR-30AB PERFORMANCE CHARACTERISTICS: TA Range L, valid at TA = – 40°C to 150°C, VCC = 5 V, unless other-
wise specified
Characteristic
Symbol
Test Conditions
Min.
Typ.1
Max.
Unit
Nominal Performance
Current-Sensing Range
IPR
–30
–
30
A
Sens
IPR(min) < IP < IPR(max)
–
66
–
mV/A
VIOUT(Q)
Bidirectional, IP = 0 A
–
VCC ×
0.5
–
V
IP = IPR(max), TA = 25°C to 150ºC
-2
±0.8
2
%
IP = IPR(max), TA = –40°C to 25ºC
-6
±4
6
%
IP = IPR(max), TA = 25°C to 150°C
-1.5
±0.8
1.5
%
Sensitivity
Zero-Current Output Voltage
Accuracy Performance
Total Output Error2
Total Output Error
ETOT
Components3
Sensitivity Error
Offset Voltage
ETOT = ESENS + 100 × VOE/(Sens × IP)
Esens
VOE
IP = IPR(max), TA = –40°C to 25°C
-5.5
±4
5.5
%
IP = 0 A, TA = 25°C to 150ºC
-10
±6
10
mV
IP = 0 A, TA = –40°C to 25ºC
-30
±6
30
mV
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift
Esens_drift
–3
±1
3
%
Total Output Error Lifetime Drift
Etot_drift
–3
±1
3
%
1 Typical
values with +/- are 3 sigma values
2 Percentage of I , with I = I
P P
PR(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 specification. Also, 3 sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
11
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
ACS724
xLLCTR-50AB PERFORMANCE CHARACTERISTICS: TA Range L, valid at TA = – 40°C to 150°C, VCC = 5 V, CF = 0,
unless otherwise specified
Characteristic
Symbol
Test Conditions
Min.
Typ.1
Max.
Unit
Nominal Performance
Current-Sensing Range
IPR
–50
–
50
A
Sens
IPR(min) < IP < IPR(max)
–
40
–
mV/A
VIOUT(Q)
Bidirectional, IP = 0 A
–
VCC ×
0.5
–
V
IP = IPR(max), TA = 25°C to 150ºC
-2
±0.8
2
%
IP = IPR(max), TA = –40°C to 25ºC
-6
±4
6
%
IP = IPR(max), TA = 25°C to 150°C
-1.5
±0.8
1.5
%
Sensitivity
Zero-Current Output Voltage
Accuracy Performance
Total Output Error2
Total Output Error
ETOT
Components3
Sensitivity Error
Offset Voltage
ETOT = ESENS + 100 × VOE/(Sens × IP)
Esens
VOE
IP = IPR(max), TA = –40°C to 25°C
-5.5
±4
5.5
%
IP = 0 A, TA = 25°C to 150ºC
-10
±6
10
mV
IP = 0 A, TA = –40°C to 25ºC
-30
±6
30
mV
Lifetime Drift Characteristics
Sensitivity Error Lifetime Drift
Esens_drift
–3
±1
3
%
Total Output Error Lifetime Drift
Etot_drift
–3
±1
3
%
1 Typical
values with +/- are 3 sigma values
2 Percentage of I , with I = I
P P
PR(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 specification. Also, 3 sigma distribution values are combined by taking the square root of the sum of the squares. See Application Information section.
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115 Northeast Cutoff
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12
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
ACS724
CHARACTERISTIC PERFORMANCE
xLLCTR-10AU
Offset Voltage vs. Temperature
515
15
510
10
Offset Voltage (mV)
VIOUT(Q) (mV)
Zero Current Output Voltage vs. Temperature
505
500
495
490
5
0
-5
-10
485
-15
-50
0
50
100
150
-50
0
Temperature (ºC)
415
4
410
3
405
400
395
390
385
1
0
-1
-2
-3
-4
-5
375
-6
50
100
150
-50
0
Temperature (ºC)
50
100
150
Temperature (ºC)
Nonlinearity vs. Temperature
Total Error at IPR(max) vs. Temperature
1.00
4
0.80
3
0.60
2
0.40
1
Total Error (%)
Nonlinearity (%)
150
2
380
0
100
Sensitivity Error vs. Temperature
Sensitivity Error (%)
Sensitivity (mV/A)
Sensitivity vs. Temperature
-50
50
Temperature (ºC)
0.20
0.00
-0.20
-0.40
0
-1
-2
-3
-0.60
-4
-0.80
-5
-6
-1.00
-50
0
50
100
150
-50
Temperature (ºC)
+3 Sigma
0
50
100
150
Temperature (ºC)
Average
-3 Sigma
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
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13
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
ACS724
xLLCTR-10AB
Offset Voltage vs. Temperature
2510
10
2508
8
2506
6
Offset Voltage (mV)
VIOUT(Q) (mV)
Zero Current Output Voltage vs. Temperature
2504
2502
2500
2498
2496
4
2
0
-2
-4
2494
-6
2492
-8
-50
0
50
100
150
-50
0
Temperature (ºC)
100
150
Sensitivity Error vs. Temperature
210
5
208
4
206
3
Sensitivity Error (%)
Sensitivity (mV/A)
Sensitivity vs. Temperature
204
202
200
198
196
193
192
2
1
0
-1
-2
-3
-4
190
-5
188
-6
-50
0
50
100
150
-50
0
Temperature (ºC)
50
100
150
Temperature (ºC)
Nonlinearity vs. Temperature
Total Error at IPR(max) vs. Temperature
1.00
5
0.80
4
0.60
3
0.40
2
Total Error (%)
Nonlinearity (%)
50
Temperature (ºC)
0.20
0.00
-0.20
-0.40
-0.60
1
0
-1
-2
-3
-4
-0.80
-5
-1.00
-6
-50
0
50
100
-50
150
Temperature (ºC)
+3 Sigma
0
50
100
150
Temperature (ºC)
Average
-3 Sigma
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
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14
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
ACS724
xLLCTR-20AU
Offset Voltage vs. Temperature
508
8
506
6
504
4
Offset Voltage (mV)
VIOUT(Q) (mV)
Zero Current Output Voltage vs. Temperature
502
500
498
496
494
2
0
-2
-4
-6
492
-8
490
-10
-50
0
50
100
150
-50
0
Temperature (ºC)
100
150
Sensitivity Error vs. Temperature
208
4
206
3
204
2
Sensitivity Error (%)
Sensitivity (mV/A)
Sensitivity vs. Temperature
202
200
198
196
194
192
1
0
-1
-2
-3
-4
190
-5
-50
0
50
100
-50
150
0
Temperature (ºC)
50
100
150
Temperature (ºC)
Nonlinearity vs. Temperature
Total Error at IPR(max) vs. Temperature
1.00
4
0.80
3
0.60
2
0.40
Total Error (%)
Nonlinearity (%)
50
Temperature (ºC)
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
-50
150
Temperature (ºC)
+3 Sigma
0
50
100
150
Temperature (ºC)
Average
-3 Sigma
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
15
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
ACS724
xLLCTR-20AB
Offset Voltage vs. Temperature
Zero Current Output Voltage vs. Temperature
10
2508
8
Offset Voltage (mV)
2510
VIOUT(Q) (mV)
2506
2504
2502
2500
2498
4
2
0
-2
-4
2496
2494
-50
6
-6
0
50
100
150
-50
0
Temperature (ºC)
104
4
103
3
102
2
Sensitivity Error (%)
Sensitivity (mV/A)
100
150
Sensitivity Error vs. Temperature
Sensitivity vs. Temperature
101
100
99
98
97
1
0
-1
-2
-3
-4
96
-5
95
-50
0
50
100
-50
150
0
50
100
150
Temperature (ºC)
Temperature (ºC)
Nonlinearity vs. Temperature
Total Error at IPR(max) vs. Temperature
1.00
4
0.80
3
0.60
2
0.40
Total Error (%)
Nonlinearity (%)
50
Temperature (ºC)
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
-50
150
Temperature (ºC)
+3 Sigma
0
50
100
150
Temperature (ºC)
Average
-3 Sigma
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
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Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
ACS724
xLLCTR-30AU
Offset Voltage vs. Temperature
Zero Current Output Voltage vs. Temperature
8
506
6
Offset Voltage (mV)
508
VIOUT(Q) (mV)
504
502
500
498
496
4
2
0
-2
-4
494
-6
492
-8
-50
0
50
100
150
-50
0
Temperature (ºC)
50
100
150
Temperature (ºC)
Sensitivity vs. Temperature
Sensitivity Error vs. Temperature
4
138
3
Sensitivity Error (%)
Sensitivity (mV/A)
136
134
132
130
2
1
0
-1
-2
-3
128
-4
126
-5
-50
0
50
100
-50
150
0
Temperature (ºC)
Nonlinearity vs. Temperature
100
150
Total Error at IPR(max) vs. Temperature
1.00
4
0.80
3
0.60
2
0.40
Total Error (%)
Nonlinearity (%)
50
Temperature (ºC)
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
-50
150
Temperature (ºC)
+3 Sigma
0
50
100
150
Temperature (ºC)
Average
-3 Sigma
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
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17
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
ACS724
xLLCTR-30AB
Offset Voltage vs. Temperature
2510
10
2508
8
2506
6
Offset Voltage (mV)
VIOUT(Q) (mV)
Zero Current Output Voltage vs. Temperature
2504
2502
2500
2498
2496
4
2
0
-2
-4
2494
-6
2492
-50
-8
0
50
100
150
-50
0
Temperature (ºC)
Sensitivity vs. Temperature
150
4
3
Sensitivity Error (%)
68
Sensitivity (mV/A)
100
Sensitivity Error vs. Temperature
69
67
66
65
64
63
2
1
0
-1
-2
-3
-4
62
-5
-50
0
50
100
-50
150
0
Temperature (ºC)
50
100
150
Temperature (ºC)
Total Error at IPR(max) vs. Temperature
Nonlinearity vs. Temperature
1.00
4
0.80
3
0.60
2
0.40
Total Error (%)
Nonlinearity (%)
50
Temperature (ºC)
0.20
0.00
-0.20
-0.40
1
0
-1
-2
-3
-0.60
-4
-0.80
-5
-1.00
-50
0
50
100
-50
150
50
100
150
Temperature (ºC)
Temperature (ºC)
+3 Sigma
0
Average
-3 Sigma
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
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18
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
ACS724
APPLICATION INFORMATION
Estimating Total Error vs. Sensed Current
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:
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 components 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:
2
Total Error (% of Current Measured)
ETOT (IP) = ESENS +
(
100 × VOE
Sens × IP
ETOTAVG (IP) = ESENSAVG +
100 × VOEAVG
Sens × IP
The resulting total error will be a sum of ETOT and ETOT_AVG.
Using these equations and the 3 sigma distributions for Sensitivity Error and Offset Voltage, the Total Error versus sensed current
(IP) is below for the ACS724LLCTR-20AB. As expected, as one
goes towards zero current, the error in percent goes towards infinity due to division by zero.
2
)
8
6
-40ºC + 3σ
4
-40ºC – 3σ
2
25ºC + 3σ
0
25ºC – 3σ
-2
85ºC + 3σ
-4
85ºC – 3σ
-6
-8
0
5
10
15
20
Current (A)
Figure 1: Predicted Total Error as a Function of the Sensed Current for the ACS724LLCTR-20AB
Allegro MicroSystems, LLC
115 Northeast Cutoff
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19
ACS724
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
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.
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:
VIOUT(IPR(max)) – VIOUT(Q)
ELIN = 1–
• 100(%)
2 • VIOUT(IPR(max)/2) – VIOUT(Q)
Increasing
VIOUT (V)
Accuracy at
25°C Only
IPR(min)
ETOT (IP) =
+IP (A)
VIOUT(Q)
–IP (A)
Full Scale IP
IPR(max)
0A
Accuracy at
25°C Only
Decreasing
VIOUT (V)
Accuracy Across
Temperature
Figure 1: Output Voltage versus Sensed Current
+ETOT
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 voltage to amperes, divide by the device sensitivity, Sens.
Total Output Error (ETOT). 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:
Accuracy at
25°C Only
Ideal VIOUT
Accuracy Across
Temperature
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 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.
Accuracy Across
Temperature
Across Temperature
25°C Only
–IP
+IP
VIOUT_ideal(IP) – VIOUT (IP)
• 100 (%)
Sensideal(IP) • IP
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 corresponding ETOT versus IP .
–ETOT
Figure 2: Total Output Error versus Sensed Current
Allegro MicroSystems, LLC
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20
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
ACS724
Sensitivity Ratiometry Coefficient (SENS_RAT_COEF). The
coefficient defining how the sensitivity scales with VCC. The
ideal coefficient is 1, meaning the sensitivity scales proportionally 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 equation:
Sens(VCC ) = Sens(5 V)
1+
(VCC – 5 V) • SENS_RAT_COEF
5V
This can be rearranged to define the sensitivity ratiometry coefficient as:
SENS_RAT_COEF =
Sens(VCC )
5V
–1 •
(VCC – 5 V)
Sens(5 V)
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 proportionality 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(VCC ) = VIOUTQ(5 V)
1+
(VCC – 5 V) • QVO_RAT_COEF
5V
This can be rearranged to define the zero-current output ratiometry coefficient as:
QVO_RAT_COEF =
VIOUTQ(VCC )
5V
–1 •
(VCC – 5 V)
VIOUTQ(5 V)
Allegro MicroSystems, LLC
115 Northeast Cutoff
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21
ACS724
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
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
VCC
VCC(typ.)
VIOUT
90% VIOUT
VCC(min.)
t1
t2
tPO
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
0
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.
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.
(%)
90
Figure 3: Power-On Time (tPO)
t
Primary Current
VIOUT
Rise Time, tr
20
10
0
Propagation Delay, tpd
t
Figure 4: Rise Time (tr) and Propagation Delay (tpd)
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.
(%)
90
Primary Current
VIOUT
Response Time, tRESPONSE
0
Figure 5: Response Time (tRESPONSE)
Allegro MicroSystems, LLC
115 Northeast Cutoff
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1.508.853.5000; www.allegromicro.com
t
22
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
ACS724
PACKAGE OUTLING 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
0.25
0.17
3.90 ±0.10
5.60
6.00 ±0.20
A
1.04 REF
1
1.75
2
1
1.27
0.40
C
2
PCB Layout Reference View
0.25 BSC
SEATING PLANE
Branded Face
GAUGE PLANE
C
8X
0.10
1.75 MAX
C
NNNNNNN
SEATING
PLANE
PPT-AAA
LLLLL
0.51
0.31
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
P = Package Designator
T = Device temperature range
A = Amperage
L = Lot number
Belly Brand = Country of Origin
Figure 6: Package LC, 8-pin SOICN
Allegro MicroSystems, LLC
115 Northeast Cutoff
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23
ACS724
Automotive-Grade, Galvanically Isolated Current Sensor IC
With Common-Mode Field Rejection in a Small-Footprint SOIC8 Package
Document Revision History
Revision
Pages
Responsible
Date
–
Added Characteristic Performance graphs and Application Information to
Preliminary draft to create Final draft
Change
All
A. Latham
January 16, 2015
1
Corrected Features and Benefits
2
A. Latham
June 19, 2015
2
Added ACS724LLCTR-50AB-T variant with electrical characteristics
2, 9
A. Latham
June 23, 2015
3
Corrected Characteristic Performance graph legends; updated Lifetime Drift
Characteristics and added Error Over Lifetime electrical characteristics
6-18
A. Latham,
S. Milano
August 12, 2015
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.
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
24
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