High-Precision Linear Hall-Effect-Based Current Sensor IC With 200 μΩ Current Conductor


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The ACS72981 family of current sensor ICs provides economical and precise solutions for AC or DC current sensing. A 250 kHz bandwidth makes it ideal for motor control, load detection and management, power supply and DC-to-DC converter control, and inverter control. The response time enables overcurrent fault detection in safety-critical applications.

The device consists of a precision, low-offset linear Hall circuit with a copper conduction path located near the die. Applied current flowing through this copper conduction path generates a magnetic field which the Hall IC converts into a proportional voltage. Device accuracy is optimized through the close proximity of the magnetic signal to the Hall transducer. A precise, proportional output voltage is provided by the low-offset, chopper-stabilized BiCMOS Hall IC, which is programmed for accuracy at the factory. Proprietary digital temperature compensation technology greatly improves the zero output voltage and output sensitivity accuracy over temperature and lifetime.

The output of the device increases when an increasing current flows through the primary copper conduction path (from terminal 5 to terminal 6), which is the path used for current sampling. The internal resistance of this conductive path is 200 μΩ typical, providing low power loss and increasing power density in the application.

The sensor employs differential sensing techniques that virtually eliminate output disturbance due to common-mode interfering magnetic field.

The thickness of the copper conductor allows survival of the device at high overcurrent conditions. The terminals of the conductive path are electrically isolated from the signal leads (pins 1 through 3).

The device is fully calibrated prior to shipment from the factory. The ACS72981 family is lead (Pb) free. All leads are plated with 100% matte tin, and there is no Pb inside the package. The heavy gauge leadframe is made of oxygen-free copper.

  • High-bandwidth 250 kHz analog output
  • Less than 2 μs output response time
  • 3.3 V and 5 V supply operation
  • Ultralow power loss: 200 μΩ internal conductor resistance
  • Industry-leading noise performance and increased
  • Greatly improved total output error through digitally programmed and compensated gain and offset over the full operating temperature range
  • Small package size, with easy mounting capability
  • Monolithic Hall IC for high reliability
  • Output voltage proportional to AC or DC currents
  • Factory-trimmed for accuracy
  • Extremely stable zero amp output offset voltage over temperature and lifetime

The ACS72981 family is lead (Pb) free. All leads are plated with 100% matte tin, and there is no Pb inside the package. The heavy gauge leadframe is made of oxygen-free copper.

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Current Sensor Error and Resolution
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Pololu Carrier Board

Mikroe Demoboards ACS72981

Pololu Robotics and Electronics offer breakout boards with support from Allegro Microsystems as an easy way to use or evaluate their ACS72981xLR Hall effect-based linear current sensors. The sensor includes 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.

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