Tinycontrol

This board is a simple carrier of Allegro’s 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 4%. It operates from 3 V to 5.5 V, so it can interface directly to both 3.3 V and 5 V systems.

This 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). Conductive path internal resistance is typically 0.6 mΩ, 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. Good accuracy and reliability: factory calibration results in a typical total output error of 4% at room temperature, the output offset voltage is extremely stable, and the sensor has zero magnetic hysteresis. Overcurrent FAULT output latches low when current magnitude exceeds 31 A. Operating temperature range of -40°C to 125°C.

The 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.

This 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” packages.