The new ACS758 from Allegro MicroSystems Europe is a thermally enhanced, high-current, Hall-effect-based linear current sensor that provides an economical and precise solution for AC or DC current sensing. The new device offers wide current range, increased device bandwidth, fast response times, reduced output noise and enhanced output accuracy. An integrated electrostatic shield is included to reduce the amount of ripple present on the device output signal when the integrated conductor is subjected to high dV/dt signals.
Featuring 50-200A current range, 120kHz bandwidth and up to four-fold reduction in output noise, the device is suitable for applications in motor control, load detection and management, power-supply and DC/DC converter control, inverter control, and overcurrent fault detection. A 3µs output risetime in response to step input current makes the device 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 the company'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 the company's proprietary integrated shield technology, provides low output ripple and low offset drift in high-side high-voltage applications. The internal resistance of this conductive path is 100µOhm. 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 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.
