Monolithic Power Systems — MCS1823 Current Sensor

Monolithic Power Systems produces the MCS1823, a linear Hall-effect current sensor which can measure both ac and dc currents. The sensor is supplied in a small 3 mm x 3 mm QFN-12 package, enabling designers to implement current sensing in a very small area of a system board.

The sensor’s array of Hall sensing elements is arranged in a differential configuration to cancel out the effect of any stray magnetic field, making it immune to magnetic interference.

The MCS1823 has a 0.6 mΩ primary conductor which allows a large current to flow close to the IC’s accurate Hall sensors. This current generates a magnetic field which is sensed at two different points by the integrated Hall transducers. The difference in magnetic field strength at these two points is converted into a voltage which is proportional to the applied current. A spinning current technique is used to give a low, stable offset.

In addition to providing current measurements, the MCS1823 also detects over-current events in a maximum response time of 1 μs. This enables design engineers to implement over-current monitoring and current sensing with a single device. The over-current detection threshold can be customized to between 50% and 240% of maximum input power.