ACS718: High Isolation Linear Current Sensor IC with 850 μΩ Current Conductor

The Allegro ACS718 current sensor IC is an economical, high isolation solution for AC or DC current sensing in industrial, commercial, and communications systems. The small package is ideal for space-constrained applications, though the wide-body provides the creepage and clearance needed for high isolation. Typical applications include motor control, load detection and management, switched-mode power supplies, and overcurrent fault protection.

The device consists of a low-offset, linear Hall sensor circuit with a copper conduction path located near the surface of the die. Applied current flowing through this copper conduction path generates a magnetic field which is sensed by the integrated Hall IC and converted into a proportional voltage. Device accuracy is optimized through the close proximity of the magnetic field to the Hall transducer. A proportional voltage is provided by the low-offset, chopper-stabilized BiCMOS Hall IC, which is programmed for accuracy after packaging. The output of the device has a positive slope when an increasing current flows through the primary copper conduction path (from pins 1 through 4, to pins 5 through 8), which is the path used for current sensing. The internal resistance of this conductive path is 0.85 mΩ typical, providing low power loss.

The terminals of the conductive path are electrically isolated from the sensor leads (pins 10 through 15 ). This allows the ACS718 current sensor IC to be used in high-side current sense applications without the use of high-side differential amplifiers or other costly isolation techniques.

The ACS718 is provided in a small, low profile surface mount SOICW16 package (suffix MA). The device is lead (Pb) free with 100% matte tin leadframe plating. The device is fully calibrated prior to shipment from the factory.