The ACS780/ACS781 integrated linear current sensor ICs come in a core-less package designed to sense ac/dc currents up to 100A. The devices consist 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 primary conductor to the Hall transducer and factory programming of the sensitivity and zero-ampere output voltage at the Allegro factory.
Chopper-stabilized signal path and digital temperature compensation technology also contribute to the stability of the devices across the operating temperature range. High-level immunity to current conductor dV/dt and stray electric fields is offered by Allegro proprietary integrated shield technology, for low-output voltage ripple and low-offset drift in high-side, high-voltage applications. The output of the device has a positive slope (>VCC / 2) when an increasing current flows through the primary copper conduction path (from terminal 8 to terminal 9), which is the path used for current sampling. The internal resistance of this conductive path is 200 μΩ typical, providing low power loss. The thickness of the copper conductor allows survival of the devices at high overcurrent conditions. The terminals of the conductive path are electrically isolated from the signal leads (pins 1 through 7, and 10), allowing the device to operate safely with voltages up to 100 V peak on the primary conductor. The ACS780xLR and ACS781xLR are both priced at $1.87 each/1,000.