This is the large version of a simple carrier for Allegro’s ACS72981LLRATR-100B3/100B5 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.

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 and 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.

Details for item #5273

This large carrier features the ACS72981LLRATR-100B3, which is intended for nominal 3.3 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 “3V3 B10” printed on the bottom side, as shown in the left picture above.

A compact carrier is also available for this sensor IC for more space-constrained applications or to evaluate the IC’s performance with a smaller PCB area for thermal dissipation.

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 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 is centered at VCC/2 and changes by 13.2 mV × (VCC/3.3 V) per amp of input current, with positive current increasing the output voltage and negative current decreasing the output voltage:

• VIOUT=VCC2+0.0132VA⋅VCC3.3V⋅IP=VCC⋅(12+IP250A)
• IP=250A⋅(VIOUTVCC–12)

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

Details for item #5274

This large 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.

A compact carrier is also available for this sensor IC for more space-constrained applications or to evaluate the IC’s performance with a smaller PCB area for thermal dissipation.

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:

• VIOUT=VCC2+0.02VA⋅VCC5V⋅IP=VCC⋅(12+IP250A)
• IP=250A⋅(VIOUTVCC–12)

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