The first fully integrated GMR-based current sensor IC from Allegro MicroSystems has been released with ultra-high sensitivity for applications that require less more than 5A current sensing. The 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 1mA resolution in a very low series resistance package of only 1 mΩ. This QFN package has an industry best 3x3mm 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 analogue output provides a low noise high-speed signal, which is proportional to the current flowing through the primary conductor. The full scale bandwidth is 1MHz and the response time of the device is typically 535ns. The ACS70331 is offered in four factory-programmed sensitivity and offset levels to optimise 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 3.3V power supply and is qualified over the full commercial temperature range of -40 to 85°C. It is offered in a low-profile space-saving surface mount QFN package.