New 1MHz bandwidth integrated Hall-effect based current sensor IC

Allegro MicroSystems Europe has announced its first 1MHz bandwidth Hall-effect current sensor IC with a lightning-fast 210ns response time. The ACS730 provides an economical and precise solution for AC or DC current sensing. The device targets industrial, commercial, and communications systems. Typical applications include motor control, load detection and management, switched-mode power supplies, and over-current fault protection. The new device consists of a precise, low-offset, linear Hall-sensor circuit with a copper conduction path located near the surface of 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 optimised through the close proximity of the magnetic field to the Hall transducer. A precise, proportional voltage is provided by the Hall IC, which is programmed for accuracy after packaging. The output of the device has a positive slope when an increasing current flows through the primary copper conduction path (from pins 1 and 2, to pins 3 and 4), which is the path used for current sensing. The internal resistance of this conductive path is typically 1.2mohm, providing low power loss. The terminals of the conductive path are electrically isolated from the sensor leads (pins 5 through 8). This allows the ACS730 current sensor IC to be used in high-side current sense applications without the use of high-side differential amplifiers or other costly isolation techniques. The ACS730 is housed in a small, low-profile surface-mount SOIC-8 package. The lead frame is plated with 100% matt tin, which is compatible with standard lead (Pb) free printed-circuit-board assembly processes. Internally, the device is Pb-free, except for flip-chip high-temperature Pb-based solder balls, currently exempt from RoHS. The device is fully calibrated prior to shipment, says the company.