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ACS72981LLRATR-100B5 Current Sensor Compact Carrier -100A to +100A, 5V
This is the compact version of a simple carrier for Allegro’s ACS72981LLRATR-100B5 Hall effect-based, electrically isolated current sensor, which offers a low-resistance (~0.2 mΩ) current path and a high 250 kHz bandwidth for fast response times.
Part Suffix | Range | Supply Voltage | Sensitivity @ 5 V | Zero Point @ 5 V | Size |
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100B5 | ±100 A (bidirectional) | 4.5 V to 5.5 V | 20 mV/A | 2.5 V | 0.7″×0.8″ |
Alternatives available with variations in these parameter(s): current range size Select variant…
Compare all products in ACS72981 Current Sensor Compact Carriers.
Description | Specs (12) | Pictures (13) | Resources (6) | FAQs (0) | On the blog (0) |
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Overview
ACS72981 Current Sensor Compact Carrier (top) and Large Carrier (bottom) size comparison. |
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We are offering these breakout boards with support from Allegro Microsystems as an easy way to use or evaluate their ACS72981xLR Hall effect-based, electrically isolated current sensors; we therefore recommend careful reading of the ACS72981 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 0.2 mΩ, and the PCB is made with 6 layers of 2-oz copper, so very little power is lost in the module.
- High-bandwidth 250 kHz analog output voltage proportional to AC or DC currents
- Less than 2 µs response time.
- Integrated digital temperature compensation circuitry allows improved accuracy over the full operating temperature range.
- 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.
- 3.3V and 5V versions available.
- Unidirectional and bidirectional versions available.
The connection points are labeled on the bottom silkscreen. The silkscreen also shows the direction that is interpreted as positive current flow via the +i arrow.
The following table lists the available ACS72981 carrier options:
Pololu Item # |
Part Suffix | Supply Voltage (V) |
Current Range | Sensitivity @ Nominal Vcc (mV/A) |
Zero Point @ Nominal Vcc (V) |
Size | Price | ||
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Large Carrier |
#5270 | 050B3 | 3.0 to 3.6 (3.3 nominal) |
Bidirectional | ±50 A | 26.4 | 1.65 | 1.4″×1.2″ | $12.95 |
#5273 | 100B3 | ±100 A | 13.2 | ||||||
#5277 | 150B3 | ±150 A | 8.8 | ||||||
#5281 | 200B3 | ±200 A | 6.6 | ||||||
#5272 | 050U3 | Unidirectional | 0-50 A | 52.8 | 0.33 | ||||
#5275 | 100U3 | 0-100 A | 26.4 | ||||||
#5279 | 150U3 | 0-150 A | 17.6 | ||||||
#5283 | 200U3 | 0-200 A | 13.2 | ||||||
#5271 | 050B5 | 4.5 to 5.5 (5 nominal) |
Bidirectional | ±50 A | 40 | 2.5 | |||
#5274 | 100B5 | ±100 A | 20 | ||||||
#5278 | 150B5 | ±150 A | 13.3 | ||||||
#5282 | 200B5 | ±200 A | 10 | ||||||
#5276 | 100U5 | Unidirectional | 0-100 A | 40 | 0.5 | ||||
#5280 | 150U5 | 0-150 A | 26.7 | ||||||
Compact Carrier |
#5250 | 050B3 | 3.0 to 3.6 (3.3 nominal) |
Bidirectional | ±50 A | 26.4 | 1.65 | 0.7″×0.8″ | $9.95 |
#5253 | 100B3 | ±100 A | 13.2 | ||||||
#5257 | 150B3 | ±150 A | 8.8 | ||||||
#5261 | 200B3 | ±200 A | 6.6 | ||||||
#5252 | 050U3 | Unidirectional | 0-50 A | 52.8 | 0.33 | ||||
#5255 | 100U3 | 0-100 A | 26.4 | ||||||
#5259 | 150U3 | 0-150 A | 17.6 | ||||||
#5263 | 200U3 | 0-200 A | 13.2 | ||||||
#5251 | 050B5 | 4.5 to 5.5 (5 nominal) |
Bidirectional | ±50 A | 40 | 2.5 | |||
#5254 | 100B5 | ±100 A | 20 | ||||||
#5258 | 150B5 | ±150 A | 13.3 | ||||||
#5262 | 200B5 | ±200 A | 10 | ||||||
#5256 | 100U5 | Unidirectional | 0-100 A | 40 | 0.5 | ||||
#5260 | 150U5 | 0-150 A | 26.7 |
Alternatives available with variations in these parameter(s): typical operating voltage current range size Select variant…
Details for item #5254
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This compact carrier features the ACS72981LLRATR-100B5, which is intended for nominal 5 V operation and is designed for bidirectional input current from -100 A to +100 A. This version can be visually distinguished from the other versions by the “5V B10” printed on the bottom side, as shown in the left picture above.
Part Suffix | Range | Supply Voltage | Sensitivity @ 5 V | Zero Point @ 5 V | Size |
---|---|---|---|---|---|
100B5 | ±100 A (bidirectional) | 4.5 V to 5.5 V | 20 mV/A | 2.5 V | 0.7″×0.8″ |
A larger carrier 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 (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. The sensor outputs a ratiometric analog voltage on VIOUT that is centered at VCC/2 and changes by 20 mV × (VCC/5 V) per amp of input current, with positive current increasing the output voltage and negative current decreasing the output voltage:
``V_"IOUT" = V_"CC" / 2 + 0.02 text(V)/text(A) * V_"CC" / (5 text(V)) * I_"P" = V_"CC" * (1/2 + I_"P" / (250 text(A)))``
``I_"P" = 250 text(A) * (V_"IOUT" / V_"CC" – 1/2)``
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. 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, as shown in the pictures below. 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. 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.
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
ACS72981 Current Sensor Carrier schematic diagram. |
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The dimension diagram is available as a downloadable PDF (400k pdf).
Real-world power dissipation considerations
Thermal image of a high-current test of a Pololu current sensor carrier (not necessarily this product). |
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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 our tests, we found that our ACS72981 carrier boards could conduct 60 A continuously while staying well below 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.
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, 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:
(1) Sensitivity when Vcc = 3.3 V; sensitivity is ratiometric.
(2) Sensitivity when Vcc = 5 V; sensitivity is ratiometric.
(3) Bandwidth can be reduced by adding a filter capacitor.
(4) ±50A version uses 4-oz copper PCB; all other versions use 2-oz copper.
(5) 50A and higher versions use 4-layer PCB; all other versions use 2-layer PCB.
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…