This board is a simple carrier of Allegro’s Â±31 A ACS711 Hall
effect-based linear current sensor with overcurrent fault output, which
offers a low-resistance (~0.6 mΩ) current path and electrical isolation
up to 100 V. This version accepts a bidirectional current input with a
magnitude up to 31 A and outputs a proportional analog voltage centered
at Vcc/2 with a typical error of Â±4%. It operates from 3 V to 5.5 V, so
it can interface directly to both 3.3 V and 5 V systems.
current sensor is a carrier board or breakout board for Allegro’s
ACS711KEXLT-31AB-T Hall effect-based linear current sensor with
overcurrent fault output; we therefore recommend careful reading of the
ACS711 datasheet (551k pdf) before using this product. This sensor has
an operating voltage of 3 V to 5.5 V and an output sensitivity of 45
mV/A when Vcc is 3.3 V (or 68 mV/A when Vcc is 5 V). The following list
details some of the sensor’s key features:
- Designed for
bidirectional input current from -31 A to 31 A (though the robust sensor
IC can tolerate 100 ms transient current spikes up to 100 A).
path internal resistance is typically 0.6 mO, and the PCB is made with
2-oz copper, so very little power is lost in the board.
- Use of a
Hall effect sensor means the IC is able to electrically isolate the
current path from the sensor’s electronics (for applications up to 100
V), which allows the sensor to be inserted anywhere along the current
path and to be used in applications that require electrical isolation.
- 100 kHz bandwith.
accuracy and reliability: factory calibration results in a typical
total output error of Â±4% at room temperature, the output offset
voltage is extremely stable, and the sensor has zero magnetic
- Overcurrent FAULT output latches low when current magnitude exceeds 31 A.
- Operating temperature range of -40Â°C to 125Â°C.
pads are labeled on the bottom silkscreen, as shown in the picture to
the right. The silkscreen also shows the direction that is interpreted
as positive current flow via the +i arrow.
This 31 A current sensor is marked with a green X.
We also sell a 15.5 A version that uses the same carrier PCB; you can
distinguish the versions by reading the text on the IC or by looking at
the color of the X on the bottom silkscreen.
sensor is very similar to our original ACS711 -25 to +25 A Current
Sensor Carrier, but uses a smaller “EX” package that has a larger
optimized sensing range and reduced internal resistance. The board size,
pinout, and hole locations are all unchanged, so it can generally be
used as a drop-in replacement for our ACS711 carriers with “LC”