ACS72981LLRATR-050U3 Current Sensor Large Carrier 0A to 50A, 3.3V

SKU: POLOLU-5272 Brand: Pololu

This is the large version of a simple carrier for Allegro’s ACS72981LLRATR-050U3 Hall effect-based, electrically isolated current sensor, which offers a...

$25.80 AUD, inc GST

$23.45 AUD, exc GST

Available with a lead time
Expect dispatch between Apr 23 and Apr 28

Quantity Discounts:

10+ $22.52 (exc GST)
25+ $21.81 (exc GST)

The ACS72981 Current Sensor Large Carrier features the ACS72981LLRATR-050U3, which is intended for nominal 3.3 V operation and is designed for unidirectional input current from 0 A to 50 A. This version can be visually distinguished from the other versions by the “3V3 U05” printed on the bottom side.

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 3.0 V to 3.6 V to be connected across the VCC and GND pads, which are labeled on the bottom silkscreen. The sensor outputs a ratiometric analog voltage on VIOUT that has a zero point at VCC/10 and increases by 52.8 mV × (VCC/3.3 V) per amp of input current:

V_IOUT = V_CC/10 + 0.0528 V/A × (V_CC/3.3 V) × I_P = V_CC × (1/10 + I_P/62.5 A)

I_P = 62.5 A × (V_IOUT / V_CC – 1/10)

The VIOUT, VCC, and GND pins work with 0.1"-pitch header pins and are compatible with standard solderless breadboards.

You can insert the board into your current path in a variety of ways. The largest through-holes are 8.4 mm in diameter with 20 mm spacing. These can be used with 5/16" or M8 screws for attaching various types of lugs or solderless ring terminals, or thick wires up to 2 AWG can be soldered directly to the board. The slots near the edge of the board can accommodate a 4-pin terminal block or other connector with a pitch between 7.5 mm and 9.5 mm. Examples of these kinds of connections are shown in the pictures below. Holes with 0.1", 3.5 mm, and 5 mm spacing are also available for connecting male header pins or terminal blocks, but please note that these smaller connection options are generally not suitable for high currents like those this sensor is intended for.

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

The dimension diagram is available as a downloadable PDF (400k pdf).

Real-world power dissipation considerations

Depending on the version, the ACS72981 can measure up to ±200 A, but its datasheet specifies an absolute maximum continuous current of 120 A. Furthermore, the sensor chip can overheat at lower currents. In Pololu's tests, Pololu found that Pololu's ACS72981 carrier boards could conduct 60 A continuously while staying well below the thermal limit for the IC. Pololu's 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.

Warning: Exceeding temperature or current limits can cause permanent damage to the sensor. If you are measuring an average continuous current greater than 50 A, Pololu 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

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

Dimensions

Size:	1.4" × 1.2"
Weight:	4.2 g

General specifications

Typical operating voltage:	3.3 V
Current sense:	52.8 mV/A¹
Minimum logic voltage:	3.0 V
Maximum logic voltage:	3.6 V
Supply current:	14 mA²
Current range:	0A to ?50A (unidirectional 50A), 3.3V
Current sensor:	Allegro ACS72981LLRATR-050U3

Identifying markings

PCB dev codes:	cs04b
Other PCB markings:	0J14823
Other PCB markings:	3V3 U05

Notes:

1: At VCC = 3.3 V.
2: Typical.

File downloads

Dimension diagrams of the ACS72981xLR Current Sensor Carriers (400k pdf)
3D model of the ACS72981xLR Current Sensor Large Carriers (3MB step)
Drill guide for the ACS72981xLR Current Sensor Large Carriers (19k dxf)

This DXF drawing shows the locations of all of the board’s holes.

Recommended links

ACS72981 datasheet
Allegro Application Note AN296169: Characterizing System Bandwidth in Complex Current Sensor Applications

This is the application note referenced on page 16 of the ACS724 datasheet, page 22 of the ACS71240 datasheet, and page 42 of the ACS72981xLR datasheet. The ACS720 is used to validate the test methods presented, but these same methods and principles would also apply to the ACS724, ACS71240, and ACS72981.
Allegro product page for the ACS72981 Hall-based Current Sensor

Allegro product page for the ACS72981, where you can find additional application notes and other resources.

This product is listed in:

Sensors>Current

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