Allegro MicroSystems, LLC introduces Allegro’s first fully integrated, GMR-based current sensor IC with ultra-high sensitivity for applications that require <5 A current sensing. Allegro’s ACS70331 current sensor IC incorporates giant magneto-resistive (GMR) technology that is 25 times more sensitive than traditional Hall-effect sensor ICs to sense the magnetic field generated by the current flowing through the low resistance, integrated primary conductor.
This new device has been designed to sense very small currents with 1 mA resolution in a very low series resistance package of only 1 mOhm. This QFN package has an industry best 3 mm x 3 mm solder footprint, providing a much smaller sensing footprint at a much lower resistance over competitive shunt and op-amp based solutions. Key applications include: handheld and laptop adaptor chargers, radios and walkie talkies, IoT load detection, small surveillance and other motor control applications.
The analog output provides a low noise high-speed signal, which is proportional to the current flowing through the primary conductor. The full scale bandwidth is 1 MHz and the response time of the device is typically 535 ns. The ACS70331 is offered in four factory-programmed sensitivity and offset levels to optimize performance over the desired current measurement range. The differential configuration of the GMR elements, relative to the integrated current conductor, provides significant rejection of stray magnetic fields, resulting in stable operation even in magnetically noisy environments.
Allegro’s ACS70331 current sensor IC operates from a single 3.3 V power supply and is qualified over the full commercial temperature range of –40°C to 85°C. It is offered in a low-profile space-saving surface mount QFN package. It is priced at $0.53 in quantities of 1,000.