ACS37030LLZATR-065B3 Current Sensor Compact Carrier -65A to +65A, 3.3V

Overview

ACS37030 Current Sensor Compact Carrier (top) and Large Carrier (bottom) size comparison.

We are offering these breakout boards with support from Allegro Microsystems as an easy way to use or evaluate their ACS37030 DC to 5 MHz bandwidth, galvanically isolated, high-accuracy current sensors with reference output; we therefore recommend careful reading of the ACS37030 datasheet before using this product. The following list details some of the sensor’s key features:

• 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.
• High bandwidth (DC to 5 MHz) analog voltage output proportional to the current.
• 40 ns typical response time.
• Two current signal paths:
  • Hall effect-based sensor for capturing DC and low-frequency current information
  • Inductive coil for capturing high-frequency current information.
• 0.7 mΩ primary current path resistance in the sensor IC, and the PCB is made with 2-layer (compact versions) or 6-layer (large versions) 2-oz copper, so very little power is lost in the module.
• 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.
• Output is not ratiometric (i.e. the zero point and sensitivity are independent of the actual supply voltage), which provides immunity from noisy supplies.
• VREF output for pseudo-differential signaling in noisy application environments.
• Integrated digital temperature compensation circuitry allows improved accuracy over the full operating temperature range.
• Automotive-grade operating temperature range of -40°C to 150°C.
• Carrier boards, available in compact and large sizes, offer a variety of ways to insert it into the current path along with 0.1″-pitch (breadboard-compatible) power, ground, and output pins.

The connection points are labeled on the silkscreen, which is on the bottom side of the compact versions and on both sides of the large versions. The bottom silkscreen also shows the direction that is interpreted as positive current flow via the +i arrow.

The following table lists the available ACS37030 carrier options:

	Pololu Item #	Part Suffix	Current Range	Sensitivity (mV/A)	Size	PCB Details	Price
Compact Carrier	#5230	020B3	±20 A	66	0.7″×0.8″	2 layers, 2-oz copper	$7.95
	#5232	065B3	±65 A	20.3
Large Carrier	#5235	065B3	±65 A	20.3	1.4″×1.2″	6 layers, 2-oz copper	$10.95

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

Details for item #5232

ACS37030LLZATR-065B3 Current Sensor Compact Carrier -65A to +65A, 3.3V, bottom view.

ACS37030 Current Sensor Compact Carrier.

This compact carrier features the ACS37030LLZATR-065B3, which is intended for nominal 3.3 V operation and is designed for bidirectional input current from -65 A to +65 A. This version can be visually distinguished from the other versions by the “65” printed on the bottom side, as shown in the left picture above.

Part Suffix	Range	Supply Voltage	Sensitivity	Zero Point	Size	PCB layers
065B3	±65 A (bidirectional)	3 V to 3.6 V	20.3 mV/A	1.65 V	0.7″×0.8″	2

A larger carrier with a 6-layer PCB is also available for this sensor IC with room for larger connectors and thicker wires for the high-current path, offering different ways to use or evaluate this current sensor.

Using the sensor

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

The sensor requires a supply voltage of 3.0 V to 3.6 V to be connected across the VDD and GND pads, which are labeled on the bottom silkscreen. The sensor outputs an analog voltage on VOUT that is centered at 1.65 V and changes by 20.3 mV per amp of input current, with positive current increasing the output voltage and negative current decreasing the output voltage:

``V_"OUT" = 1.65 text(V) + 0.0203 text(V)/text(A) * I_"P"``

``I_"P" = (V_"OUT" – 1.65 text(V)) / (0.0203 text(V)/text(A)) = (V_"OUT" – 1.65 text(V)) * 49.3 text(A)/text(V)``

The output is not ratiometric, so the zero point and sensitivity are independent of the actual supply voltage.

The zero-current reference voltage, which is available on VREF, can be used to reduce errors due to reference shifts or noise on the ground line.

Making connections to the board

You can insert the board into your current path in a variety of ways. For typical high-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 10 AWG wires or #6 or M3.5 screws, and the second-largest through-holes (and mounting holes) are sized for 14 AWG wires or #2 or M2 screws. Holes with 0.1″, 3.5 mm, and 5 mm spacing are also available as shown in the diagram above for connecting male header pins or terminal blocks, but please note that these connection options will generally not be suitable for the kinds of high currents intended for this sensor. The pictures below show examples of various connection options with the ACS37220 compact carrier, which has the same physical dimensions as the ACS37030 compact carrier.

The VREF, VOUT, VDD, and GND pins work with 0.1″-pitch header pins and are compatible with standard solderless breadboards

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

ACS37030 Current Sensor Carrier schematic diagram.

The dimension diagram is available as a downloadable PDF (421k pdf).

Real-world power dissipation considerations

Thermal image of a high-current test of a Pololu current sensor carrier (not necessarily this product).

Depending on the version, the ACS37220 can measure up to ±65 A. However, the sensor chip can overheat at lower currents. In our tests, we found that our ACS37030 compact carrier boards could conduct about 55 A continuously without reaching the thermal limit for the IC. Our tests were conducted at approximately 25°C ambient temperature with no forced air flow.

The actual current you can pass through the sensor will depend on how well you can keep it cool. The carrier’s printed circuit board is designed to help with this by drawing heat out of the sensor chip. Solid connections to the current path pins (such as with thick soldered wires or large, tightly-secured lugs) can also help reduce heat build-up in the sensor and carrier board, as can switching to the equivalent large carrier version.

Warning: Exceeding temperature or current limits can cause permanent damage to the sensor. If you are measuring an average continuous current greater than 45 A, we strongly recommend that you monitor the sensor’s temperature and look into additional cooling if necessary.

This product can get hot enough to burn you long before the chip overheats. Take care when handling this product and other components connected to it.

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…