ACS71240
Automotive-Grade, Galvanically Isolated Current Sensor IC
with Common-Mode Field Rejection and Overcurrent Detection
in Small Footprint Low-Profile Packages
FEATURES AND BENEFITS
DESCRIPTION
• AEC-Q100 automotive qualified
The Allegro™ ACS71240 current sensor IC is an economical
• 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
andprecisesolutionforACorDCcurrentsensinginindustrial,
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
generatesamagneticfieldwhichissensedbytheintegratedHall
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 theAllegro 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.
• UL certified package (SOIC-8 only) for voltage isolation
TheACS71240isprovidedinsmall,low-profilesurface-mount
packageoptions:QFN-12withwettableflankandSOIC-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-
chiphigh-temperaturePb-basedsolderballs, currentlyexempt
from RoHS. The device is fully calibrated prior to shipment
from the factory.
PACKAGES:
12-contact QFN with wettable flank
3 mm × 3 mm × 0.75 mm
(EXB package)
8-pin SOIC
with internally fused path
(LCB package)
Not to scale
V
CC
VCC
CBYP
0.1 μF
IP+
IP+
SOIC-8 ONLY
TÜV America
Certificate Number:
U8V 14 11 54214 032
CB 14 11 54214 031
VIOUT
CLOAD
IP
ACS71240
RPU
FAULT
IP–
CB Certificate Number:
US-22334-A3-UL
IP–
GND
Figure 1: Typical Application
ACS71240-DS
MCO-0000621
March 7, 2019