ACS724LLCTR-20AB Current Sensor Carrier -20A to +20A

Overview

We are offering these breakout boards with support from Allegro Microsystems as an easy way to use or evaluate their ACS724LLCTR Hall effect-based, electrically isolated current sensors; we therefore recommend careful reading of the ACS724 datasheet before using this product. The following list details some of the sensor’s key features:

• Hall effect-based sensor with electrically isolated current path allows the sensor to be inserted anywhere along the current path and to be used in applications that require electrical isolation.
• Differential Hall sensing rejects common-mode fields, so the orientation of the sensor relative to uniform external magnetic fields (e.g. the Earth’s magnetic field) has less effect on the measurement.
• The conductive path internal resistance is typically 1.2 mΩ, and the PCB is made with 2-oz or 4-oz copper, depending on the sensor version, so very little power is lost in the module.
• High-bandwidth 120 kHz analog output voltage proportional to AC or DC currents.
• Typical 4 µs response time.
• Optional FILTER pin simplifies bandwidth limiting for better noise reduction and improved resolution at lower frequencies.
• Integrated digital temperature compensation circuitry allows for near closed loop accuracy over temperature in an open loop sensor.
• Automotive-grade operating temperature range of -40°C to 150°C.
• 0.7″×0.8″ carrier board offers a variety of ways to insert it into the current path along with 0.1″-pitch (breadboard-compatible) power, ground, and output pins.
• Unidirectional and bidirectional versions available.

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.

A variety of options are available with different current sensing ranges and sensitivities:

Alternatives available with variations in these parameter(s): current range Select variant…

These versions all look very similar, and while you can distinguish them by reading the text on the IC, we also provide a white box on the bottom silkscreen where you can add your own distinguishing markings if so desired.

Details for item #4045

ACS724LLCTR-20AB Current Sensor Carrier -20A to +20A, top view.

ACS724LLCTR-20AB Current Sensor Carrier -20A to +20A with included 0.1″ header pins.

This carrier features the ACS724LLCTR-20AB, which operates at 5 V and is designed for bidirectional input current from -20 A to +20 A. This version can be visually distinguished from the other versions by the “20AB” written on the IC as shown in the pictures above.

Part Suffix	Range	Sensitivity @ 5 V	Zero Point @ 5 V	Supply Voltage
20AB	±20 A (bidirectional)	100 mV/A	2.5 V	4.5 V to 5.5 V

When Vcc is 5 V, the output voltage is centered at 2.5 V and changes by 100 mV per amp of input current, with positive current increasing the output voltage and negative current decreasing the output voltage. More generally, the sensor’s zero point and sensitivity depend on VCC as follows:

``text(Zero Point) = V_"CC" / 2``

``text(Sensitivity) = 0.1 text(V)/text(A) * (1 + ((V_"CC" – 5 text(V)) * 1.3) / (5 text(V)))``

This board ships assembled with all surface mount components, and a 3×1 strip of 0.1″ header pins is included but not soldered in.

Using the sensor

This sensor has five required connections: the input current (IP+ and IP-), logic power (VCC and GND), and the sensor output (VIOUT).

The sensor requires a supply voltage of 4.5 V to 5.5 V to be connected across the VCC and GND pads, which are labeled on the bottom silkscreen, and the sensor outputs an analog voltage with a linear relationship to the input current:

``V_"IOUT" = text(Zero Point) + text(Sensitivity) * I_"P"``

``I_"P" = (V_"IOUT" – text(Zero Point)) / text(Sensitivity)``

The FILTER pin lets you adjust the board’s bandwidth by adding a capacitor to ground (a ground pad has been added next to the FILTER pin for convenience) in parallel with the 1 nF capacitor that is already on the board. Without an added external filter capacitor, the bandwidth is about 90 kHz. The datasheet provides more information on how the filter capacitors affect bandwidth.

You can insert the board into your current path in a variety of ways. For low-current applications, you can solder 0.1″ male header pins to the board via the smallest pair of through-holes on the input-current side of the board. For higher-current applications, you can solder wires directly to the through-holes that best match your wires, or you can use solderless ring terminal connectors. The largest through-holes are big enough for 8 AWG wires or #6 or M3.5 screws, and the second-largest through-holes (and mounting holes) are sized for 12 AWG wires or #2 or M2 screws.

Warning: This product is intended for use below 30 V. Working with higher voltages can be extremely dangerous and should only be attempted by qualified individuals with appropriate equipment and experience.

Schematic and dimension diagrams

Schematic diagram of the ACS724 Current Sensor Carrier.

The dimension diagram is available as a downloadable PDF (1MB pdf).

Comparison of the Pololu current sensor carriers

We have a variety of current sensors available with different ranges, sensitivities, and features. The table below summarizes our selection of active and preferred options:

You can also use the following selection box to see all these options sorted by current range:

Alternatives available with variations in these parameter(s): current range Select variant…

People often buy this product together with:

ACS724LLCTR-05AB Current Sensor Carrier -5A to +5A

ACS724LLCTR-10AU Current Sensor Carrier 0A to 10A

ACS724LLCTR-30AU Current Sensor Carrier 0A to 30A