Allegro MicroSystems’ ACS772 5V and ACS773 3.3V current sensor ICs for ac or dc current sensing feature a 200-kHz bandwidth and can detect current levels up to 400A. Their 2.5-µs response time enables overcurrent fault detection in safety-critical applications. The devices boast an accuracy of ±2.1% over their lifetime of the IC.
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 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 IC accuracy and temperature stability.
High-level immunity to current conductor dV/dt and stray electric fields is offered by a proprietary integrated shield technology for low output voltage ripple and low offset drift in high-side, high-voltage applications. The output of the device increases when increasing current flows through the primary copper conduction path (from terminal 4 to terminal 5), which is the path used for current sampling. The internal resistance of this conductive path is 100 μΩ typical, providing low power loss. 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).