May 22, 2012
Worcester, MA – Allegro MicroSystems, Inc. announces a new current sensor IC that provides an economical and precise solution for AC or DC current sensing in 3.3 V supply applications. This new device is targeted at the automotive and industrial markets. Typical applications include motor control, load detection and management, power supply and DC-to-DC converter control, inverter control, and overcurrent fault detection.
The device consists of a precision, low-offset linear Hall sensor circuit with a copper conduction path located near 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 signal to the Hall transducer. A precise, proportional voltage is provided by the low-offset, chopper-stabilized BiCMOS Hall IC, which is programmed for accuracy at the factory. High level immunity to current conductor dV/dt and stray electric fields, offered by Allegro proprietary integrated shield technology, guarantees low ripple at output 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 4 to terminal 5), which is the path used for current sensing.
The internal resistance of this conductive path is 100 µΩ typical, providing low power loss. The thickness of the copper conductor allows for 200 A continuous current sensing applications and survival to much higher transient currents. The terminals of the conductive path are electrically isolated from the sensor leads (pins 1 through 3). This allows the ACS759 family of sensors to be used in applications requiring electrical isolation without the use of opto-isolators or other costly isolation techniques. The device is fully calibrated prior to shipment from the factory.
The ACS759 senor IC is lead (Pb) free. All leads are plated with 100% matte tin, and there is no lead inside the package. The heavy gauge leadframe is made of oxygen-free copper. It is available in a small 5-pin CB package with easy mounting capability.