Current sensor offers 50-200A and low output noise

The new device offers a number of performance enhancements compared to Allegro’s earlier generation of current sensors, including a wider current range, increased device bandwidth and faster response times, reduced output noise, enhanced output accuracy, and the inclusion of an integrated electrostatic shield to drastically reduce the amount of ripple present on the device output signal when the integrated conductor is subjected to high dV/dt signals.

Featuring a 50-200 A current range, 120 kHz bandwidth and up to a fourfold reduction in output noise, the ACS758 is ideally suited to applications in motor control, load detection and management, power-supply and DC/DC converter control, inverter control, and overcurrent fault detection.

A 3 µs output risetime in response to step input current makes the ACS758 suitable for short-circuit protection applications, while an anti-aliasing filter eliminates ripple in average current measurements on motors, inverters and DC/DC converters.

The device consists of a precision, low-offset linear Hall sensor circuit with a copper conduction path located near the Hall sensor 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 optimised through the close proximity of the magnetic signal to the Hall transducer, and through the integration of a high-performance ferromagnetic core into Allegro’s custom CB package. A precise, proportional voltage is provided by the low-offset, chopper-stabilised BiCMOS Hall IC, which is programmed for accuracy at the factory.
The high level of immunity to current conductor dV/dt signals and stray electric fields, offered by Allegro’s proprietary integrated shield technology, guarantees low output ripple and low offset drift in high-side high-voltage applications. The internal resistance of this conductive path is typically 100 microhms, which means that power losses are very small.
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 sensor leads, allowing the device to be used in applications requiring electrical isolation without the use of opto-isolators or other costly isolation techniques.

The ACS758 family is lead (Pb) free. All leads are plated with 100% matt tin, and there is no lead inside the package. The heavy gauge leadframe is made of oxygen-free copper.