Not to scale
The Allegro™ ACS71240 current sensor IC is an economical
and precise solution for AC or DC current sensing in industrial,
automotive, commercial, and communications applications.
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 path
generates a magnetic field which is sensed by the integrated Hall
IC and converted into a proportional voltage. The resistance of
the integrated conductor is far less than typical sense resistors,
which reduces power loss and improves efficiency.
Rejection of external common-mode magnetic fields is
achieved through differential sensing, enabling high accuracy
in magnetically noisy environments. A precise voltage
proportional to the measured current is generated by the low-
offset, chopper-stabilized Hall front end.
Zero ampere output voltage and device sensitivity are
programmed at the Allegro factory to provide a high accuracy
solution across the full automotive temperature range.
The ACS71240 includes an integrated fault comparator for
simplified overcurrent detection. The ultrafast response time
provides the system with ample time to detect and protect
against short-circuit events.
The ACS71240 is provided in small, low-profile surface-mount
package options: QFN-12 with wettable flank and SOIC-8. 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.
ACS71240-DS, Rev. 2
MCO-0000621
• AEC-Q100 automotive qualified
• Differential Hall sensing rejects common-mode fields
• 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
• Patented integrated digital temperature compensation
circuitry allows for near closed-loop accuracy over
temperature in an open loop sensor
• Single supply operation with nonratiometric output at
3.3 and 5 V options
• Overcurrent FAULT available between 50% and 200% IP
with 1.5 µs (typ) response time
• Non-ratiometric output provides immunity to noisy supplies
• Small footprint QFN-12 with wettable flank and SOIC-8
suitable for space-constrained automotive applications
• 0.6 mΩ (QFN-12) or 1.2 mΩ (SOIC-8) primary
conductor resistance for low power loss and high inrush
current withstand capability
• UL certified package (SOIC-8 only) for voltage isolation
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
Figure 1: Typical Application
IP+
IP+
IP–
IP–
IP
GND
ACS71240
VCC
VIOUT
VCC CBYP
0.1 μF
CLOAD
RPU
FAULT
FEATURES AND BENEFITS DESCRIPTION
PACKAGES:
12-contact QFN with wettable flank
3 mm × 3 mm × 0.75 mm
(EXB package)
ACS71240
July 24, 2019
8-pin SOIC
with internally fused path
(LCB package)
CB Certicate Number:
US-22334-A3-UL
TÜV America
Certificate Number:
U8V 14 11 54214 032
CB 14 11 54214 031
SOIC-8 ONLY
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
ACS71240
2
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
SELECTION GUIDE
Part Number
Supply
Voltage, VCC
(V)
Optimized
Accuracy
Range, IPR (A)
Sensitivity
(Typ)
(mV/A)
Fault Trip
Level (A)
Operating Ambient
Temperature Range,
TA (°C)
Package Packing [1]
ACS71240KEXBLT-010B3 3.3 ±10 132 ±10
–40 to 125
12-contact QFN with
wettable flank
(EXB)
1500 pieces
per 7-inch reel
ACS71240KEXBLT-030B3 3.3 ±30 44 ±30
ACS71240KEXBLT-050U5 5.0 50 80 50
ACS71240KEXBLT-010B3-115 3.3 ±10 132 ±11.5
ACS71240LLCBTR-010B3 3.3 ±10 132 ±10
–40 to 150
8-pin SOIC with
internally fused path
(LCB)
3000 pieces
per 13-inch reel
ACS71240LLCBTR-030B3 3.3 ±30 44 ±30
ACS71240LLCBTR-045B5 5 ±45 44.4 ±45
ACS71240LLCBTR-050U5 5 50 80 50
[1] Contact Allegro for additional packing options.
Naming Specification
ACS71240KEXBTR -010B3
Supply Operating Level, VCC
3 = 3.3 V
5 = 5.0 V
Optimized Accuracy Range, IPR
Packing Option
Package Type
EXB = QFN-12 Package with Wettable Flank
LCB = SOIC-8 Package
Operating Temperature Range, TA
K = –40°C to 125°C (QFN-12 only)
L = –40°C to 150°C (SOIC-8 only)
Allegro Current Sensor 5-digit part number
Current Polarity
B = Bidirectional
U = Unidirectional
Custom Fault Level, IFAULT
115 = 115% IPR
[blank] = 100% IPR
-115
LT = 1500 pieces per 7-inch reel (QFN-12 only)
TR = 3000 pieces per 13-inch reel (SOIC-8 only)
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
ACS71240
3
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
ABSOLUTE MAXIMUM RATINGS
Characteristic Symbol Notes Rating Units
Supply Voltage VCC 6 V
Reverse Supply Voltage VCC(R) –0.5 V
Output Voltage VIOUT VCC + 0.7 V
Reverse Output Voltage VIOUT(R) –0.5 V
FAULT Voltage VFAULT 25 V
Reverse FAULT Voltage VFAULT(R) –0.5 V
Operating Ambient Temperature Range TA
Range K (QFN-12 package) –40 to 125 °C
Range L (SOIC-8 package) –40 to 150 °C
Junction Temperature TJ(MAX) 165 °C
Storage Temperature Range Tstg –65 to 170 °C
ISOLATION CHARACTERISTICS (for SOIC-8 package only)
Characteristic Symbol Notes Value Units
Dielectric Surge Strength Test Voltage VSURGE Tested ±5 pulses at 2/minute in compliance to IEC 61000-4-5
1.2 µs (rise) / 50 µs (width). 6000 V
Dielectric Strength Test Voltage 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
Working Voltage for Basic Isolation VWVBI Maximum approved working voltage for basic (single)
isolation according to UL 60950-1 (edition 2)
420 VPK or VDC
297 VRMS
Clearance Dcl Minimum distance through air from IP leads to signal leads 4.2 mm
Creepage Dcr Minimum distance along package body from IP leads to
signal leads 4.2 mm
ISOLATION CHARACTERISTICS (for QFN-12 package only)
Characteristic Symbol Notes Value Units
Working Voltage for Basic Isolation [1] VWVBI Voltage applied between pins 1-4 and 5-12 100 VPK or VDC
[1] Based on characterization. No agency testing was conducted.
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
ACS71240
4
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
Terminal List Table (QFN-12)
Number Name Description
1, 2 IP+ Positive terminals for current being sensed; fused internally
3, 4 IP– Negative terminals for current being sensed; fused internally
5 GND Signal ground terminal
6FAULT Overcurrent fault; active low
7, 8, 9, 10 NC No connection; connect to ground for optimal ESD performance
11 VIOUT Analog output signal
12 VCC Device power supply terminal
Package EX, 12-Pin QFN
Pinout Diagram
PINOUT DIAGRAMS AND TERMINAL LIST TABLES
10
9
8
7
1
2
3
4
5
6
12
11
VCC
VIOUT
GND
FAULT
NC
NC
NC
NC
IP+
IP+
IP–
IP–
Terminal List Table (SOIC-8)
Number Name Description
1, 2 IP+ Positive terminals for current being sensed; fused internally
3, 4 IP– Negative terminals for current being sensed; fused internally
5 GND Signal ground terminal
6FAULT Overcurrent fault; active low
7 VIOUT Analog output signal
8 VCC Device power supply terminal
Package LC, 8-Pin SOIC
Pinout Diagram
IP+
IP+
IP–
IP–
VCC
VIOUT
FAULT
GND
1
2
3
4
8
7
6
5
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
ACS71240
5
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
Temperature
Sensor
VCC
FAULT
VIOUT
GND
EEPROM and
Control Logic
Master Current
Supply
Power On
Reset
Programming
Control
Offset
Control
Sensitivity
Control
Hall
Current
Drive
IP+
IP+
IP–
IP–
Dynamic Offset
Cancellation
Fault Delay
Logic
To All Subcircuits
Fault
Comparator
Functional Block Diagram
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
ACS71240
6
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
Characteristic Symbol Test Conditions Min. Typ. [1] Max. Unit
ELECTRICAL CHARACTERISTICS
Supply Voltage VCC
5 V variant 4.5 5.0 5.5 V
3.3 V variant 3.0 3.3 3.6 V
Supply Current ICC
5 V variant, no load on VIOUT – 10 12 mA
3.3 V variant, no load on VIOUT – 7.5 12 mA
Output Capacitance Load CLVIOUT to GND – – 4.7 nF
Output Resistive Load RLVIOUT to GND 10 – – kΩ
Primary Conductor Resistance RIP TA = 25°C QFN-12 package – 0.6 – mΩ
SOIC-8 package – 1.2 – mΩ
Primary Hall Coupling Factor G1TA = 25°C QFN-12 package – 10 – G/A
SOIC-8 package – 11 – G/A
Secondary Hall Coupling Factor G2TA = 25°C QFN-12 package – –2 – G/A
SOIC-8 package – –2.8 – G/A
Hall Plate Sensitivity Matching Sensmatch TA = 25°C – ±1 – %
Common Mode Field Rejection CMFR Offset due to DC
common field
QFN-12 package – 1.2 – mA/G
SOIC-8 package – 0.6 – mA/G
Rise Time trTA = 25°C, CL = 1 nF; input current step causing
1 V output swing – 3 4 [2] μs
Propagation Delay tpd TA = 25°C, CL = 1 nF; input current step causing
1 V output swing – 1.6 2.2 [2] μs
Response Time tRESPONSE TA = 25°C, CL = 1 nF; input current step causing
1 V output swing – 4 4.9 [2] μs
Bandwidth BW Small signal –3 dB; CL = 1 nF – 120 – kHz
Noise Density IND
VCC = 5.0 V, input referred, TA = 25°C, CL = 1 nF – 100 – µARMS/
√Hz
VCC = 3.3 V, input referred, TA = 25°C, CL = 1 nF 150 µARMS/
√Hz
Noise IN
VCC = 5.0 V, input referred, TA = 25°C, CL = 1 nF – 52 – mARMS
VCC = 3.3 V, input referred, TA = 25°C, CL = 1 nF – 78 – mARMS
Nonlinearity ELIN
Up to IP = 10 A QFN-12 package –1 – 1 %
Through full range of IPSOIC-8 package –1 – 1 %
Power Supply Rejection Ratio PSRR
VCC = VCC ±10%, TA = 25°C, DC to 1 kHz – 40 – dB
VCC = VCC ±10%, TA = 25°C, 1 kHz to 20 kHz – 30 – dB
VCC = VCC ±10%, TA = 25°C, 20 kHz to 60 kHz – 20 – dB
Output Saturation Voltage
[3] VSAT_H RL = 10 kΩ VCC – 0.3 – – V
VSAT_L RL = 10 kΩ – – 0.3 V
Power-On Time tPO Output reaches 90% of steady-state level,
TA = 25°C, IP = IPR(max) applied – 80 – μs
Shorted Output-to-Ground Current ISC(GND) TA = 25°C – 30 – mA
Shorted Output-to-VCC Current ISC(VCC) TA = 25°C – 1.8 – mA
COMMON ELECTRICAL CHARACTERISTICS: Valid through the full range of TA and VCC, unless otherwise specied
Continued on next page...
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
ACS71240
7
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
Characteristic Symbol Test Conditions Min. Typ. [1] Max. Unit
FAULT CHARACTERISTICS
FAULT Operating Point IFAULT – ±1 × IPR [4] – A
FAULT Current Hysteresis IF(HYS) Percent of IPR(MAX) 3 5 – %
FAULT Output Pullup Resistor RPU 10 – 500 kΩ
FAULT Output Voltage VOL RPU = 10 kΩ, during fault condition – – 0.3 V
FAULT Response Time tFAULT
Time from |IP| rising above |IFAULT| until VFAULT <
VOL(MAX). 100 pF from FAULT to GND.
Input current step 20% above IFAULT with rise time
≤ 1 µs.
– 1.5 2.5 [5] µs
FAULT Error EF
IFAULT, TA = 25°C –10 ±3.5 10 %
TA = –40°C or TA(MAX) –10 ±5 10 %
[1] Typical values with ± are 3 sigma values.
[2] Guaranteed by design. Limit calculated using 6 sigma. Not tested in production.
[3] The sensor IC will continue to respond to current beyond the range of IP until the high or low saturation voltage; however, the nonlinearity in this region will be worse than
through the rest of the measurement range.
[4] Unless otherwise specied, contact Allegro for alternative fault levels. Available from ±0.5 to 2 × IPR.
[5] Not tested in production.
COMMON ELECTRICAL CHARACTERISTICS (continued): Valid through the full range of TA and VCC, unless otherwise specied
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
ACS71240
8
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
ACS71240KEXBLT-010B3 PERFORMANCE CHARACTERISTICS: Over full range of TA, VCC = 3.3 V, unless otherwise specied
Characteristic Symbol Test Conditions Min. Typ. [1] Max. Unit
NOMINAL PERFORMANCE
Optimized Sensing Range IPR –10 – 10 A
Sensitivity Sens IPR(min) < IP < IPR(max) – 132 – mV/A
Zero-Current Output Voltage VIOUT(Q) Bidirectional, IP = 0 A – 1.65 – V
ACCURACY PERFORMANCE
Total Output Error [2] ETOT
IP = 10 A, TA = 25°C to 125°C –2.5 ±1.4 2.5 %
IP = 10 A, TA = –40°C to 25°C –6 ±1.8 6 %
TOTAL OUTPUT ERROR COMPONENTS [3] ETOT = ESENS + 100 × VOE / (Sens × IP)
Sensitivity Error ESENS
IP = 10 A, TA = 25°C to 125°C –2 ±1.1 2 %
IP = 10 A, TA = –40°C to 25°C –5.5 ±1.7 5.5 %
Offset Voltage Error VOE
IP = 0 A, TA = 25°C to 125°C –15 ±9.7 15 mV
IP = 0 A, TA = –40°C to 25°C –30 ±8.5 30 mV
ACCURACY PERFORMANCE INCLUDING LIFETIME DRIFT [4]
Total Output Error Including
Lifetime Drift [5] ETOT_drift
IP = 10 A, TA = 25°C to 125°C –5.7 ±1.8 5.7 %
IP = 10 A, TA = –40°C to 25°C –6 ±1.5 6 %
Sensitivity Error Including
Lifetime Drift [6] ESENS_drift
IP = 10 A, TA = 25°C to 125°C –5.1 ±1.2 5.1 %
IP = 10 A, TA = –40°C to 25°C –5.6 ±1.2 5.6 %
Offset Voltage Error Including
Lifetime Drift [7] VOE_drift
IP = 0 A, TA = 25°C to 125°C –28 ±4.5 28 mV
IP = 0 A, TA = –40°C to 25°C –30 ±4.3 30 mV
[1] Typical values with ± are 3 sigma values, except for lifetime drift, which are the average value including drift (from the worst case stress) after AEC-Q100 qualication.
[2] Percentage of IP.
[3] A single device will not have both the maximum/minimum sensitivity error and maximum/minimum o󰀨set voltage, as that would violate the maximum/minimum total output
error specication.
[4] Lifetime drift characteristics are based on AEC-Q100 qualication results.
[5] All devices stayed within min/max limits throughout AEC-Q100 qualication. The worst drift observed was 6.1%.
[6] All devices stayed within min/max limits throughout AEC-Q100 qualication. The worst drift observed was 4%.
[7] All devices stayed within min/max limits throughout AEC-Q100 qualication. The worst drift observed was 22 mV.
ACS71240KEXBLT-010B3-115 Variant
Characteristic Symbol Test Conditions Min. Typ. [1] Max. Unit
NON-STANDARD FAULT CHARACTERISTICS
FAULT Operating Point IFAULT –±1.15 × IPR – A
[1] Typical values with ± are 3 sigma values
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
ACS71240
9
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
ACS71240KEXBLT-030B3 PERFORMANCE CHARACTERISTICS: Over full range of TA, VCC = 3.3 V, unless otherwise specied
Characteristic Symbol Test Conditions Min. Typ. [1] Max. Unit
NOMINAL PERFORMANCE
Optimized Sensing Range IPR –30 – 30 A
Sensitivity Sens IPR(min) < IP < IPR(max) – 44 – mV/A
Zero-Current Output Voltage VIOUT(Q) Bidirectional, IP = 0 A – 1.65 – V
ACCURACY PERFORMANCE
Total Output Error [2] ETOT
IP = 10 A, TA = 25°C to 125°C –2.5 ±0.8 2.5 %
IP = 10 A, TA = –40°C to 25°C –6 ±1.9 6 %
TOTAL OUTPUT ERROR COMPONENTS [3] ETOT = ESENS + 100 × VOE / (Sens × IP)
Sensitivity Error ESENS
IP = 10 A, TA = 25°C to 125°C –2 ±0.9 2 %
IP = 10 A, TA = –40°C to 25°C –5.5 ±1.5 5.5 %
Offset Voltage Error VOE
IP = 0 A, TA = 25°C to 125°C –15 ±3.71 15 mV
IP = 0 A, TA = –40°C to 25°C –30 ±7.1 30 mV
ACCURACY PERFORMANCE INCLUDING LIFETIME DRIFT [4]
Total Output Error Including
Lifetime Drift [5] ETOT_drift
IP = 10 A, TA = 25°C to 125°C –5.7 ±1.8 5.7 %
IP = 10 A, TA = –40°C to 25°C –6 ±1.5 6 %
Sensitivity Error Including
Lifetime Drift [6] ESENS_drift
IP = 10 A, TA = 25°C to 125°C –5.1 ±1.2 5.1 %
IP = 10 A, TA = –40°C to 25°C –5.6 ±1.2 5.6 %
Offset Voltage Error Including
Lifetime Drift [7] VOE_drift
IP = 0 A, TA = 25°C to 125°C –28 ±4.5 28 mV
IP = 0 A, TA = –40°C to 25°C –30 ±4.3 30 mV
[1] Typical values with ± are 3 sigma values, except for lifetime drift, which are the average value including drift (from the worst case stress) after AEC-Q100 qualication.
[2] Percentage of IP.
[3] A single device will not have both the maximum/minimum sensitivity error and maximum/minimum o󰀨set voltage, as that would violate the maximum/minimum total output
error specication.
[4] Lifetime drift characteristics are based on AEC-Q100 qualication results.
[5] All devices stayed within min/max limits throughout AEC-Q100 qualication. The worst drift observed was 6.1%.
[6] All devices stayed within min/max limits throughout AEC-Q100 qualication. The worst drift observed was 4%.
[7] All devices stayed within min/max limits throughout AEC-Q100 qualication. The worst drift observed was 22 mV.
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
ACS71240
10
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
ACS71240KEXBLT-050U5 PERFORMANCE CHARACTERISTICS: Over full range of TA, VCC = 5.0 V, unless otherwise specied
Characteristic Symbol Test Conditions Min. Typ. [1] Max. Unit
NOMINAL PERFORMANCE
Optimized Sensing Range IPR 0 – 50 A
Sensitivity Sens IPR(min) < IP < IPR(max) – 80 – mV/A
Zero-Current Output Voltage VIOUT(Q) Unidirectional, IP = 0 A – 0.5 – V
ACCURACY PERFORMANCE
Total Output Error [2] ETOT
IP = 10 A, TA = 25°C to 125°C –2.5 ±1.2 2.5 %
IP = 10 A, TA = –40°C to 25°C –6 ±3.6 6 %
TOTAL OUTPUT ERROR COMPONENTS [3] ETOT = ESENS + 100 × VOE / (Sens × IP)
Sensitivity Error ESENS
IP = 10 A, TA = 25°C to 125°C –2 ±0.9 2 %
IP = 10 A, TA = –40°C to 25°C –5.5 ±3.3 5.5 %
Offset Voltage Error VOE
IP = 0 A, TA = 25°C to 125°C –10 ±4.6 10 mV
IP = 0 A, TA = –40°C to 25°C –30 ±6.3 30 mV
ACCURACY PERFORMANCE INCLUDING LIFETIME DRIFT [4]
Total Output Error Including
Lifetime Drift [5] ETOT_drift
IP = 10 A, TA = 25°C to 125°C –5.7 ±1.8 5.7 %
IP = 10 A, TA = –40°C to 25°C –6 ±1.5 6 %
Sensitivity Error Including
Lifetime Drift [6] ESENS_drift
IP = 10 A, TA = 25°C to 125°C –5.1 ±1.2 5.1 %
IP = 10 A, TA = –40°C to 25°C –5.6 ±1.2 5.6 %
Offset Voltage Error Including
Lifetime Drift [7] VOE_drift
IP = 0 A, TA = 25°C to 125°C –28 ±4.5 28 mV
IP = 0 A, TA = –40°C to 25°C –30 ±4.3 30 mV
[1] Typical values with ± are 3 sigma values, except for lifetime drift, which are the average value including drift (from the worst case stress) after AEC-Q100 qualication.
[2] Percentage of IP.
[3] A single device will not have both the maximum/minimum sensitivity error and maximum/minimum o󰀨set voltage, as that would violate the maximum/minimum total output
error specication.
[4] Lifetime drift characteristics are based on AEC-Q100 qualication results.
[5] All devices stayed within min/max limits throughout AEC-Q100 qualication. The worst drift observed was 6.1%.
[6] All devices stayed within min/max limits throughout AEC-Q100 qualication. The worst drift observed was 4%.
[7] All devices stayed within min/max limits throughout AEC-Q100 qualication. The worst drift observed was 22 mV.
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
ACS71240
11
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
ACS71240LLCBTR-010B3 PERFORMANCE CHARACTERISTICS: Over full range of TA, VCC = 3.3 V, unless otherwise specied
Characteristic Symbol Test Conditions Min. Typ. [1] Max. Unit
NOMINAL PERFORMANCE
Optimized Sensing Range IPR –10 – 10 A
Sensitivity Sens IPR(min) < IP < IPR(max) – 132 – mV/A
Zero-Current Output Voltage VIOUT(Q) Bidirectional, IP = 0 A – 1.65 – V
ACCURACY PERFORMANCE
Total Output Error [2] ETOT
IP = IPR(max), TA = 25°C to 150°C –2 ±1 2 %
IP = IPR(max), TA = –40°C to 25°C –6 ±2.4 6 %
TOTAL OUTPUT ERROR COMPONENTS [3] ETOT = ESENS + 100 × VOE / (Sens × IP)
Sensitivity Error ESENS
IP = IPR(max), TA = 25°C to 150°C –1.5 ±0.84 1.5 %
IP = IPR(max), TA = –40°C to 25°C –5.5 ±2.3 5.5 %
Offset Voltage Error VOE
IP = 0 A, TA = 25°C to 150°C –10 ±6.7 10 mV
IP = 0 A, TA = –40°C to 25°C –30 ±10 30 mV
[1] Typical values with ± are 3 sigma values. All devices stayed within limits during AEC-Q100 qualication.
[2] Percentage of IP, with IP = IPR(max).
[3] A single device will not have both the maximum/minimum sensitivity error and maximum/minimum o󰀨set voltage, as that would violate the maximum/minimum total output
error specication.
ACS71240LLCBTR-030B3 PERFORMANCE CHARACTERISTICS: Over full range of TA, VCC = 3.3 V, unless otherwise specied
Characteristic Symbol Test Conditions Min. Typ. [1] Max. Unit
NOMINAL PERFORMANCE
Optimized Sensing Range IPR –30 – 30 A
Sensitivity Sens IPR(min) < IP < IPR(max) – 44 – mV/A
Zero-Current Output Voltage VIOUT(Q) Bidirectional, IP = 0 A – 1.65 – V
ACCURACY PERFORMANCE
Total Output Error [2] ETOT
IP = IPR(max), TA = 25°C to 150°C –2 ±0.6 2 %
IP = IPR(max), TA = –40°C to 25°C –6 ±1.4 6 %
TOTAL OUTPUT ERROR COMPONENTS [3] ETOT = ESENS + 100 × VOE / (Sens × IP)
Sensitivity Error ESENS
IP = IPR(max), TA = 25°C to 150°C –1.9 ±0.53 1.9 %
IP = IPR(max), TA = –40°C to 25°C –5.5 ±1.1 5.5 %
Offset Voltage Error VOE
IP = 0 A, TA = 25°C to 150°C –10 ±7.2 10 mV
IP = 0 A, TA = –40°C to 25°C –30 ±9.5 30 mV
[1] Typical values with ± are 3 sigma values. All devices stayed within limits during AEC-Q100 qualication.
[2] Percentage of IP, with IP = IPR(max).
[3] A single device will not have both the maximum/minimum sensitivity error and maximum/minimum o󰀨set voltage, as that would violate the maximum/minimum total output
error specication.
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
ACS71240
12
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
ACS71240LLCBTR-045B5 PERFORMANCE CHARACTERISTICS: Over full range of TA, VCC = 5 V, unless otherwise specied
Characteristic Symbol Test Conditions Min. Typ. [1] Max. Unit
NOMINAL PERFORMANCE
Optimized Sensing Range IPR –45 – 45 A
Sensitivity Sens IPR(min) < IP < IPR(max) – 44.4 – mV/A
Zero-Current Output Voltage VIOUT(Q) Bidirectional, IP = 0 A – 2.5 – V
ACCURACY PERFORMANCE
Total Output Error [2] ETOT
IP = IPR(max), TA = 25°C to 150°C –2 ±0.73 2 %
IP = IPR(max), TA = –40°C to 25°C –6 ±1.4 6 %
TOTAL OUTPUT ERROR COMPONENTS [3] ETOT = ESENS + 100 × VOE / (Sens × IP)
Sensitivity Error ESENS
IP = IPR(max), TA = 25°C to 150°C –1.9 ±0.63 1.9 %
IP = IPR(max), TA = –40°C to 25°C –5.5 ±1.4 5.5 %
Offset Voltage Error VOE
IP = 0 A, TA = 25°C to 150°C –10 ±6.9 10 mV
IP = 0 A, TA = –40°C to 25°C –30 ±7.2 30 mV
[1] Typical values with ± are 3 sigma values. All devices stayed within limits during AEC-Q100 qualication.
[2] Percentage of IP, with IP = IPR(max).
[3] A single device will not have both the maximum/minimum sensitivity error and maximum/minimum o󰀨set voltage, as that would violate the maximum/minimum total output
error specication.
ACS71240LLCBTR-050U5 PERFORMANCE CHARACTERISTICS: Over full range of TA, VCC = 5.0 V, unless otherwise specied
Characteristic Symbol Test Conditions Min. Typ. [1] Max. Unit
NOMINAL PERFORMANCE
Optimized Sensing Range IPR 0 – 50 A
Sensitivity Sens IPR(min) < IP < IPR(max) – 80 – mV/A
Zero-Current Output Voltage VIOUT(Q) Unidirectional, IP = 0 A – 0.5 – V
ACCURACY PERFORMANCE
Total Output Error [2] ETOT
IP = IPR(max), TA = 25°C to 150°C –2 ±1.1 2 %
IP = IPR(max), TA = –40°C to 25°C –6 ±3.75 6 %
TOTAL OUTPUT ERROR COMPONENTS [3] ETOT = ESENS + 100 × VOE / (Sens × IP)
Sensitivity Error ESENS
IP = IPR(max), TA = 25°C to 150°C –1.9 ±1.1 1.9 %
IP = IPR(max), TA = –40°C to 25°C –5.5 ±3.8 5.5 %
Offset Voltage Error VOE
IP = 0 A, TA = 25°C to 150°C –10 ±4 10 mV
IP = 0 A, TA = –40°C to 25°C –30 ±5.5 30 mV
[1] Typical values with ± are 3 sigma values. All devices stayed within limits during AEC-Q100 qualication.
[2] Percentage of IP, with IP = IPR(max).
[3] A single device will not have both the maximum/minimum sensitivity error and maximum/minimum o󰀨set voltage, as that would violate the maximum/minimum total output
error specication.
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
ACS71240
13
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
FUNCTIONAL DESCRIPTION
Power-On Reset Operation
Power-On Reset (POR) refers to the voltage at which the device
effectively turns on. In order to ensure accuracy of readings, the
part remains off or “in POR” until the voltage reaches a point at
which the device can be trusted. At this point the output leaves
high Z and begins reporting the current.
The descriptions in this section assume: TA = 25°C, no output load
(RL, CL), and no significant magnetic field is present. Refer to
the scope plot in Figure 2 for the intended power on/off profile of
the ACS71240. The device tested below contains a pull-down on
VIOUT, forcing the output voltage to 0 V during the high Z portion.
Figure 2: Power On/O󰀨 Prole of ACS71240
ICC = Green, VIOUT = Red, VCC = Yellow
Power-On
As VCC ramps up, the device output is high impedance (pink sec-
tion) until VCC reaches POR.
Power-Off
As VCC drops below POR the device output will enter a high
impedance state.
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
ACS71240
14
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
Figure 3: Output Voltage versus Sensed Current
Figure 4: Total Output Error versus Sensed Current
0 A
Decreasing
V
IOUT
(V)
Accuracy Across
Temperature
Accuracy Across
Temperature
Accuracy Across
Temperature
Accuracy at
25°C Only
Accuracy at
25°C Only
Accuracy at
25°C Only
Increasing
V
IOUT
(V)
Ideal V
IOUT
I
PR
(min)
I
PR
(max)
+I
P
(A)
–I
P
(A)
V
IOUT(Q)
Full Scale I
P
+IP
–IP
+ETOT
–ETOT
Across Temperature
25°C Only
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 ampli-
fier gain is programmed at the factory to optimize the sensitivity
(mV/A) for the full-scale current of the device.
Nonlinearity (ELIN). The nonlinearity is a measure of how linear
the output of the sensor IC is over the full current measurement
range. The nonlinearity is calculated as:
E=
LIN
1–
V(I)–V
IOUT PR(max) IOUT(Q)
2•V(I /2) –V
IOUT PR(max) IOUT(Q)
• 100(%)
Zero-Current Output Voltage (VIOUT(Q)). The output of the
sensor when the primary current is zero. For unipolar devices
this value will be 10% of operating voltage, 0.5 V and 0.33 V for
5 V and 3.3 V respectively. For bidirectional devices, the output
will be 50% of the operating voltage, 2.5 V and 1.65 V for 5 V
and 3.3 V devices respectively. Since the ACS71240 is a non-
ratiometric part, these values will be stable over VCC variations.
Variation in VIOUT(Q) can be attributed to the resolution of the
Allegro linear IC quiescent voltage trim and thermal drift.
Offset Voltage (VOE). The deviation of the device output from its
ideal quiescent value due to nonmagnetic causes. To convert this
voltage to amperes, divide by the device sensitivity, Sens.
Total Output Error (ETOT). The difference between the cur-
rent measurement from the sensor IC and the actual current (IP),
relative to the actual current. This is equivalent to the difference
between the ideal output voltage and the actual output voltage,
divided by the ideal sensitivity, relative to the current flowing
through the primary conduction path:
E(I)
TOTP
V(I)–V (I )
IOUT_ideal PIOUT P
Sens (I )•I
ideal PP
• 100 (%)
=
The Total Output Error incorporates all sources of error and is a
function of IP. At relatively high currents, ETOT will be mostly
due to sensitivity error, and at relatively low currents, ETOT will
be mostly due to Offset Voltage (VOE). In fact, at IP = 0, ETOT
approaches infinity due to the offset. This is illustrated in Figure
3 and Figure 4. Figure 3 shows a distribution of output voltages
versus IP at 25°C and across temperature. Figure 4 shows the cor-
responding ETOT versus IP .
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
ACS71240
15
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
Power Supply Rejection Ratio (PSRR). The ratio of the change
on VIOUT to a change in VCC in dB.
PSRR = 20 log
10
ΔV
CC
ΔV
IOUT
(| |)
FAULT Error (EF). The difference between the current at which
the FAULT pin trips (IFAULT), relative to the ideal fault current
(IFAULT_ideal). This is equivalent to the difference between the
ideal fault current and the actual fault current divided by the ideal
current, and is defined as:
(%)
–×E
I
II
100
_
_
F
FAULTideal
FAULTFAULT ideal
=
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
ACS71240
16
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
Fault Behavior
The ACS71240 is available with both a latched and unlatched
FAULT pin output. Unless otherwise stated, the default operation
is unlatched. Contact Allegro for more details.
Unlatched Fault Behavior
In the event that the FAULT pin is unlatched, the FAULT output
will only assert while an overcurrent condition is present. When
an overcurrent condition occurs, the FAULT pin will be pulled
low within FAULT response time, tFAULT. When the overcurrent
condition is removed, another tFAULT will delay the release of the
line, after which the FAULT line will return to VCC with a time
constant based on the pull-up resistor and line capacitance.
Latched Fault Behavior
In the event that the fault pin is latched, the FAULT output will
assert when an overcurrent condition is present. The FAULT
pin will remain latched even after the overcurrent condition has
subsided. The FAULT pin will remain asserted until the device is
power-cycled.
Fault Filtering
To prevent nuisance tripping while in latched mode, the
ACS71240 is available with a variety of minimum fault times,
which are the minimum period a fault event must be present
before the FAULT pin will latch. This minimum period, tPW(MIN),
may be 0 µs, 0.5 µs, or 1 µs, and is available upon request. Con-
tact Allegro for more details.
In latched mode, there is an additional delay of 1 clock cycle
(tCLK < 150 ns) after the overcurrent event occurs. The fault
behavior for latched and unlatched modes are shown in Figure 6
and Figure 7.
FAULT
I
FAULT
I
Applied
t
FAULT
t
FAULT
Figure 5: Fault trip with response time
Latched
Unlatched
time
FAULT < tCLK
tPW(MIN)
Figure 6: Fault event longer than tPW(MIN)
Latched
Unlatched
time
FAULT < tCLK
tPW(MIN)
Figure 7: Fault event shorter than tPW(MIN)
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
ACS71240
17
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
DEFINITIONS OF DYNAMIC RESPONSE CHARACTERISTICS
Power-On Time (tPO). When the supply is ramped to its operat-
ing voltage, the device requires a finite time to power its internal
components before responding to an input magnetic field.
Power-On Time, tPO , is defined as the time it takes for the output
voltage to settle within ±10% of its steady-state value under an
applied magnetic field, after the power supply has reached its
minimum specified operating voltage, VCC(min), as shown in the
chart at right.
Rise Time (tr). The time interval between a) when the sensor
reaches 10% of its full-scale value, and b) when it reaches 90% of
its full-scale value.
Response Time (tRESPONSE). The time interval between a) when
the sensed input current reaches 90% of its final value, and b)
when the sensor output reaches 90% of its full-scale value.
Propagation Delay (tpd
). The time interval between a) when
the sensed input current reaches 20% of its full-scale value, and
b) when the sensor output reaches 20% of its full-scale value.
VIOUT
V
t
VCC
VCC(min.)
90% VIOUT
0
t1= time at which power supply reaches
minimum specified operating voltage
t2=
time at which output voltage settles
within ±10% of its steady state value
under an applied magnetic field
t1t2
tPO
V
CC
(typ.)
Primary Current
VIOUT
90
0
(%)
Response Time, tRESPONSE
t
Primary Current
VIOUT
90
10
20
0
(%)
Propagation Delay, tpd
Rise Time, tr
t
Figure 8: Power-On Time (tPO)
Figure 9: Rise Time (tr) and Propagation Delay (tpd)
Figure 10: Response Time (tRESPONSE)
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
ACS71240
18
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
Common-Mode Field Rejection
The ACS71240 features two Hall-effect sensors used differen-
tially in order to eliminate stray field. The two sensors are placed
on opposite sides of the current loop. This allows the common
magnetic field to be determined and removed before the signal
is sent to the end user. Despite this common field rejection, it is
always best practice to reduce the amount of stray fields around
the current sensor as much as possible. See the Allegro Applica-
tions note on reducing common mode field for more details.
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
ACS71240
19
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
Figure 11: Package EXB, 12-Contact QFN
with Fused Sensed Current Loop
and Wettable Flank
PACKAGE OUTLINE DRAWINGS
0.30
Branded Face
1.00
1
12
0.50
0.70
0.85
1.27
MIN
0.80
MIN
2.90
2.05 REF
2.70
C
C
SEATING
PLANE
0.25 +0.05
–0.07
0.40±0.10
0.50 BSC 0.75 ±0.05
3.00 ±0.05
3.00 ±0.05
D
DCoplanarity includes exposed current path and terminals
B
ATerminal #1 mark area
BFused sensed current path
For reference only, not for tooling use (reference JEDEC MO-220WEED
except for fused current path and wettable flank)
Dimensions in millimeters
Exact case and lead configuration at supplier discretion within limits shown
CReference land pattern layout (reference IPC7351
QFN50P300X300X80-17W4M);
All pads a minimum of 0.20 mm from all adjacent pads; adjust as
necessary to meet application process requirements and PCB layout
tolerances; when mounting on a multilayer PCB, thermal vias at the
exposed thermal pad land can improve thermal dissipation (reference
EIA/JEDEC Standard JESD51-5)
12
2
1
A
12
1
2
PCB Layout Reference View
C0.08
9X
Branding scale and appearance at supplier discretion
E
EStandard Branding Reference View
N = Device part number
Y = Last two digits of year of manufacture
W = Week of manufacture
L
= Lot number
NNNN
YYWW
LLLL
1
0.05 REF
0.075 REF
0.74
1.50
1.36
F
F
F
FF2
F1
Hall elements (F1 and F2); not to scale
F
1.31
2.20
0.20
1.79
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
ACS71240
20
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
Figure 12: Package LCB, 8-Pin SOIC
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
C
SEATING
PLANE
1.27 BSC
A
B
B
C
21
8
Branding scale and appearance at supplier discretion
C
C0.10
8X
0.25 BSC
1.04 REF
1.75 MAX
4.90 ±0.10
3.90 ±0.10 6.00 ±0.20
0.51
0.31 0.25
0.10
0.25
0.17
1.27
0.40
8°
0°
A
Standard Branding Reference Vi
ew
21
8
C
0.65 1.27
5.60
1.75
Branded Face SEATING PLANE
GAUGE PLANE
Terminal #1 mark area
Reference land pattern layout (reference IPC7351 SOIC127P600X175-8M);
all pads a minimum of 0.20 mm from all adjacent pads; adjust as necessary
to meet application process requirements and PCB layout tolerances.
PCB Layout Reference View
1
Line 1, 2: 8 characters
Belly Brand: 5 characters
Line 1: Part Number
Line 3: First 8 characters of Assembly Lot Number
Belly Brand: Country of Origin
Lot Number
XXXXXXXX
Lot Number
1.52
2.01
0.44
D
D
D
D
D1 D2
Hall elements (D1 and D2); not to scale
DD
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
ACS71240
21
Allegro MicroSystems
955 Perimeter Road
Manchester, NH 03103-3353 U.S.A.
www.allegromicro.com
For the latest version of this document, visit our website:
www.allegromicro.com
Revision History
Number Date Description
– March 7, 2019 Initial release
1 May 31, 2019 Updated TUV certificate mark
2 July 24, 2019 Added Hall elements to LC package drawing (page 20)
Copyright 2019, Allegro MicroSystems.
Allegro MicroSystems 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 assumes no responsibility for its use; nor
for any infringement of patents or other rights of third parties which may result from its use.
Copies of this document are considered uncontrolled documents.